2014 ELECTRICAL INSPECTOR INSTRUCTORS' MANUAL LEVEL I

2014 NEC Instructor Manual and Student Worksheets -- Level 1 1

2014

ELECTRICAL INSPECTOR

INSTRUCTORS’ MANUAL

LEVEL I

NC Code Officials Qualification Board 322 Chapanoke Road

Raleigh, NC 27603


Article Title Code Page Manual Page

90 INTRODUCTION TO THE NEC 70-23 3

100 DEFINITIONS 70-27 9

110 REQUIREMENTS FOR ELECTRICAL INSTALLATIONS 70-36 13

200 USE AND IDENTIFICATION OF GROUNDED CONDUCTORS 70-49 20

210 BRANCH CIRCUITS 70-51 25

215 FEEDERS 70-64 33

220 BRANCH CIRCUIT, FEEDER AND SERVICE CALCULATIONS 70-66 37

225 OUTSIDE BRANCH CIRCUITS AND FEEDERS 70-76 49

230 SERVICES 70-83 57

240 OVERCURRENT PROTECTION 70-94 63

250 GROUNDING AND BONDING 70-106 73

280 SURGE ARRESTOR 70-139 89

300 WIRING METHODS 70-142 92

310 CONDUCTORS FOR GENERAL WIRING 70-154 101

312 CABINETS, CUTOUT BOXES, AND METER SOCKET ENCLOSURES

70-180 106

314 OUTLET, DEVICE, PULL, AND JUNCTION BOXES; CONDUIT BODIES; FITTINGS; AND HANDHOLE ENCLOSURES

70-184 110

320 ARMORED CABLE : TYPE AC 70-193 115

322 FLAT CABLE ASSEMBLIES: TYPE FC 70-195 118

324 FLAT CONDUCTOR CABLE: TYPE FCC 70-196 121

330 METAL-CLAD CABLE: TYPE MC 70-200 124

334 NONMETALLIC-SHEATHED CABLE: TYPES NM, NMC, AND NMS 70-203 127

338 SERVICE-ENTRANCE CABLE: TYPES SE AND USE

USE 70-207 134

340 UNDERGROUND FEEDER AND BRANCH-CIRCUIT CABLE: TYPE UF 70-208 138

342 INTERMEDIATE METAL CONDUIT: TYPE IMC 70-209 142

344 RIGID METAL CONDUIT: TYPE RMC 70-210 174

348 FLEXIBLE METAL CONDUIT: TYPE FMC 70-212 155

350 LIQUIDTIGHT FLEXIBLE METAL CONDUIT: TYPE LFMC 70-214 158

352 RIGID POLYVINYL CHLORIDE CONDUIT: TYPE PVC 70-215 163

354 NONMETALLIC UNDERGROUND CONDUIT WITH CONDUCTORS: TYPE NUCC

70-219 169

358 ELECTRICAL METALLIC TUBING: TYPE EMT 70-225 172

366 AUXILIARY GUTTERS 70-229 175

380 MULTIOUTLET ASSEMBLY 70-240 178

386 SURFACE METAL RACEWAYS 70-244 182

388 SURFACE NONMETALLIC RACEWAYS 70-245 182

394 CONCEALED KNOB-AND-TUBE WIRING 70-257 188

400 FLEXIBLE CORDS AND CABLES 70-262 193

402 FIXTURE WIRES 70-273 197

404 SWITCHES 70-277 200

406 RECEPTACLES, CORD CONNECTORS, AND ATTACHMENT PLUGS (CAPS) 70-281 207

408 SWITCHBOARDS AND PANELBOARDS 70-285 211


410 LUMINAIRES, LAMPHOLDERS, AND LAMPS 70-292 216

411 LIGHTING SYSTEMS OPERATING AT 30 VOLTS OR LESS AND LIGHTING EQUIPMENT CONNECTED TO CLASS-2 POWER SOURCES

70-301 227

422 APPLIANCES 70-302 229 424 FIXED ELECTRIC SPACE-HEATING EQUIPMENT 70-308 238

430 MOTORS, MOTOR CIRCUITS, AND CONTROLLERS 70-323 248

440 AIR-CONDITIONING AND REFRIGERATING

EQUIPMENT 70-351 265

504 INTRINSICALLY SAFE SYSTEMS 70-410 273

514 MOTOR FUEL DISPENSING FACILITIES 70-443 276

517 HEALTH CARE FACILITIES 70-462 281

518 ASSEMBLY OCCUPANCIES 70-481 284

545 MANUFACTURED BUILDINGS 70-501 288

547 AGRICULTURAL BUILDINGS 70-502 291

550 MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME PARKS 70-504 295

551 RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS 70-514 299

552 PARK TRAILERS 70-526 303

553 FLOATING BUILDINGS 70-535 306

555 MARINAS AND BOATYARDS 70-536 309

590 TEMPORARY INSTALLATIONS 70-540 314

600 ELECTRIC SIGNS AND OUTLINE LIGHTING 70-543 317

605 OFFICE FURNISHINGS 70-550 325

680 SWIMMING POOLS, FOUNTAINS, AND SIMILAR INSTALLATIONS 70-604 329

690 SOLAR PHOTOVOLTAIC (PV) SYSTEMS 70-623 336

702 OPTIONAL STANDBY SYSTEMS 70-661 342

705 INTERCONNECTED ELECTRICAL POWER PRODUCTION SOURCES 70-662 346

800 COMMUNICATIONS CIRCUITS 70-709 349

THE PAGE NUMBER LISTED ABOVE CORRESPONDS TO THE ARTICLE LOCATION IN THE NORTH

CAROLINA ELECTRIC CODE BOOK (THE NEC 2014). THE “TM” NUMBERS TO THE RIGHT OF THE ARTICLE

NUMBERS CORRESPONDS TO THE PAGE NUMBERS IN THE TRAINING MANUAL FOR THE STARTING PAGE

FOR EACH ARTICLE LISTED.


INTRODUCTION TO THE NATIONAL ELECTRIC CODE

ARTICLE 90

LEVEL I

OBJECTIVES:

Each student should become familiar with:

1. The purpose and scope of the National Electrical Code.

2. The definitions and Fundamental rules covered by the Code.

MATERIALS NEEDED:

National Electrical Code (NEC) most recent edition 2014 with NC Amendments.

INTRODUCTION:

This may be the student’s first contact with the National Electrical Code. The Inspector

will be working by these rules for their entire career in the electrical industry. The importance

of learning the purposes and organization of t*he Code cannot be overemphasized.

This lesson should give the students a clear picture of how the Code is organized so they

may find information more easily in later assignments and on the job. The Code is not a set of

laws; it is a set of rules. It is intended for use by governmental bodies exercising legal

jurisdiction over electrical installations and for use by insurance inspectors.

PRESENTING THE LESSON:

The National Electrical Code, Article 90, Introduction, outlines the purpose and explains

the scope, arrangement, enforcement, and formal interpretations of the Code. It also contains

details of safety examinations of equipment, future wiring expansion and units of

measurement used in the Code.

The purpose of this code is to safeguard people and property from electrical hazards by

outlining provisions that are necessary for safety. Many hazards that occur are due to

overloading wiring systems or exceeding the provisions of this Code; therefore, it is important to

plan for future increases in the use of electricity.

This code is not an instruction manual for untrained persons. Many areas are covered by

this Code, but there are also a lot of areas not covered. Pay close attention to the requirements

listed in Section 90.2.


90.2 Scope 90.2(b)(5) Explain #5 “controlled by electric utilities”. 90.2(c) Special Permission. See Administration and Enforcement Code(Sec. 308) 90.4 Enforcement. See Administration and Enforcement. 90.5 Mandatory Rules, Permissive Rules and Explanatory Materials. 90.6 Formal Interpretations. See Administration and Enforcement Code. 90.7 Examination of Equipment for Safety. See Administration and Enforcement Code. 90.8 Wiring Planning

Remind the students that the chief electrical inspectors usually exercise legal jurisdiction

over electrical installations through city ordinances or laws based on the NEC.

The instructor should lead a class discussion of the material contained in the appropriate

sections of the code. After each section distribute the worksheets for the students to

complete and answer any questions they may have.

APPLICATION:

If time will allow, go over the questions on the worksheet. This is usually a good point to

remind them to work outside of the class on their worksheets.

CHECKING AND FOLLOW-UP:

If time will allow, correct the worksheets and discuss the results.


INTRODUCTION TO THE NATIONAL ELECTRIC CODE

ARTICLE 90

LEVEL I

WORKSHEET

1. Which of the following is the purpose of this code?

a. The protection of persons and property from hazards arising from the use of

electricity.

b. The practical use of electricity and the protection of property.

c. The safeguarding of persons and property from electrical hazards.

d. The practical safeguarding of persons and property from hazards arising from the use of

electricity.

2. This code contains provisions considered necessary for which of the following?

a. Efficient, convenient, and adequate installations.

b. Allowance for good service or expansion of electrical use.

c. Installation that allows for ease of operation and safety.

d. Safety.

3. This code is not intended for which of the following?

a. As an instructional manual.

b. As a design specification.

c. Neither of the above.

d. Both of the above.

4. This code does not cover which of the following?

a. carnivals

b. aircraft

c. floating buildings

d. recreational vehicles

5. Chapter 8 and Chapter 9 cover which of the following?

a. communication, tables and annexes.

b. wiring methods, tables and appendixes.

c. tables, appendixes and conduit bodies.

d. references, standards and tables.


6. This code is intended to be suitable for mandatory application by which types of bodies

exercising legal jurisdiction over electrical installations and for use by which type of inspectors?

a. Legal and local.

b. Local and State.

c. State and Federal. d. Governmental and insurance.

7. The authority having jurisdiction may waive specific requirements in this code or permit alternate methods by which of the following?

a. By special legislation.

b. By special administrative ruling.

c. By special hearings.

d. By special permission.

8. If specified equipment has been listed by a qualified electrical testing laboratory, then under

any circumstances it is the intent of the Code not to require inspection of the factory-installed

internal wiring at the time of the installation, except for which of the following purposes?

a. To determine compliance with UL.

b. To determine compliance with NFPA.

c. To detect alterations or damage.

d. To determine proper wiring clearances.

9. Limiting the number of circuits in a single enclosure will minimize the effects from which of the following from occurring?

a. short circuits

b. ground faults

c. neither of the above

d. both of the above

10. For the purpose of this Code, metric units of measurement are in accordance with the

modernized metric system known as which of the following?

a. SI units

b. IS units

c. Centigrade units

d. Fahrenheit units


INTRODUCTION TO THE NATIONAL ELECTRIC CODE ARTICLE 90

LEVEL I

ANSWER KEY

1-d. practical safeguarding [90.1(a)]

2-d. Safety [90.1(b)]

3-d. Both of the above. [90.1(a)]

4-b. aircraft [90.2(b)(1)]

5-a. communication, tables, annexes [90.3]

6-d. governmental, insurance [90.4]

7-d. by special permission [90.4]

8-c. to detect alterations or damage [90.7]

9-d. both of the above [90.8b]

10-a. SI units [90.9(b)]


DEFINITIONS

ARTICLE 100

LEVEL I

OBJECTIVE:

Each student should become acquainted with definitions peculiar to and essential to the

proper use of the NEC.

INTRODUCTION:

This lesson should give the inspector a clear understanding of terms used in the NEC. The

definitions included in Article 100 are terms used in one or more articles of the Code.

Definitions specific to only one section are given in that section. This lesson is limited to Part

A of Article 100 which contains definitions applicable to terms used throughout the Code. It serves as an example for the instructor to use as various other definitions are discussed.


The instructor should lead a class discussion on definitions, giving illustrations of each. Example: Branch Circuit – The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s) (Show examples with slides, on chalkboard, or using actual materials if available) Stress these key definitions: Accessible and Readily Accessible In sight from Bathroom Labeled and Listed (refer to Bonded NC General Statute 66) Branch Circuit Outlet Continuous Load Overcurrent Dwelling Units Overload Feeder Receptacles Ground and Grounded Separately Derived Systems All definitions pertaining to grounding Services Ground-Fault Circuit-Interrupter Thermally Protected and Ground-Fault Protection of Equipment Protector

APPLICATION:

If time allows, have the students answer the questions on the worksheet. CHECKING AND

FOLLOW-UP:

If time allows, correct the worksheets and discuss the results.


DEFINITIONS

ARTICLE 100

LEVEL I

WORKSHEET

1. The definition of approved is which of the following?

a. listed by “UL”

b. any product that has been tested and labeled by a third party independent

safety testing laboratory

c. acceptable to the authority having jurisdiction

d. acceptable when a letter is written by the factory

2. Which of the following is the current in amperes a conductor can carry continuously under the

conditions of use without exceeding the temperature rating of the conductor?

a. full load current

b. volts

c. ohms

d. ampacity

3. Which of the following is a remote control circuit?

a. a circuit with a thermal overload or equivalent device

b. an electrical circuit with a service factor

c. an electrical circuit that controls any other circuit through a relay or equivalent device

d. an electrical circuit controlled by a master circuit controller

4. What is a Service Cable?

a. Service conductors made up in the form of a cable. b. The overhead service conductors from the last pole connecting to the service-

entrance conductor at the building.

c. Conductors between the terminals of the service equipment and the point tapped to

the service drop

d. None of the above.


5. A “dwelling unit” is defined as which of the following?

a. A single unit, providing complete and independent living facilities for one or more

persons, including permanent provisions for living, sleeping, cooking, and sanitation

service.

b. A one or two-family, providing complete and independent living facilities for three or more persons, including permanent provisions for living, sleeping, cooking, and

sanitation.

c. A room in a motel with permanent cooking facilities.

d. An apartment with permanent cooking facilities.


DEFINITIONS

ARTICLE 100

LEVEL I

ANSWER KEY

1. c, acceptable to the authority having jurisdiction

2. d, Ampacity

3. c, an electrical circuit that controls any other circuit through a relay or an equivalent

device.

4. a, Service conductors made up in the form of a cable

5. a, A single unit, providing complete and independent living facilities for one

or more persons, including permanent provisions for living, sleeping,

cooking, and sanitation.


REQUIREMENTS FOR ELECTRICAL INSTALLATIONS

ARTICLE 110

LEVEL I

OBJECTIVES:

Each student should become familiar with the terminology used in the NEC and basic rules not found elsewhere in the Code.

INTRODUCTION:

This article introduces students to the wording used in the Code. This should prevent misinterpreting

certain terminology used in the Code. It also covers basic rules that in general do not fit elsewhere in

the Code.


Mandatory rules in the Code will be indicated by the word “shall”. Anything meant to be

explanatory will be done in a Fine Print Note (FPN).

Any wiring of both equipment and conductors required or permitted by this code shall only be

acceptable if approved. (110.2)

All equipment must be examined and judged as to their approval. Any and all equipment

must be installed according to all listing and labeling. (110.3(B))

All conductors shall be copper unless otherwise stated and sizes shall be that of copper.

(110.5) Conductor sizes shall also be in AWG or circular mills. (110.6)

All wiring and equipment shall be used according to the environment in which it has been approved

(110.11)

All equipment shall be installed in a neat and workmanlike manner. All unused openings in

equipment enclosures shall be closed to the equivalent of the walls of the enclosure. Enclosures of

size large enough for persons to enter for maintenance shall have conductors racked to provide safe

and ready access. [110.12(A & B)]

(This item is covered in more detail in other Sections).

Equipment shall be firmly mounted on the surface on which it is attached and wooden plugs in

masonry shall not be approved. In equipment mounting, consideration shall be given to circulation of

air and heat dissipation so as not to block with adjacent walls and ceilings. [110.13(A & B)]


When splicing conductors, approved devices shall be used and installed according to

manufacturer’s instructions. Soldered splices shall be made mechanically secure before

soldering. Dissimilar metals (i.e., copper and aluminum) shall not be intermixed unless the

device is approved for that purpose. Terminals shall be designed so as not to damage the

conductor and shall be by pressure connector (including set screw), solder lugs, or splices to

leads. Wire binding screws and upturned lugs shall not be used on wire sized larger than #10.

[110.14(A)] Underground connectors or splicing means shall be listed for such use.

[110.14(B)]

Ampacity of a conductor is selected so as not to exceed the lowest temperature rating of the

termination. [110.14(C)]

110.14(C)(1)(a) Circuits rated 100 amperes or less or marked for 14 AWG through 1 AWG

shall be terminated with conductors rated 60° C (140° F) unless the equipment is listed and

marked otherwise

110.14(C)(1)(b) Circuits rated over 100 amperes or marked for conductors larger than 1 AWG

shall be terminated with conductors rated 75° (167° F).

All 600 volt and less equipment that requires either inspection or servicing while

equipment is energized requires a space at least 30 inches wide and a depth according to

that in Table 110.26(A).

Refer to Table 110.26(A)(1) Working Spaces:

Condition #1 is when there are exposed live parts on one side of the working space and no

grounded parts on the other or exposed live parts on both sides, insulated or cut off.

Condition #2 consists of exposed live parts on one side and grounded parts on the other.

Condition #3 has exposed live parts on both sides of the working space.

Working space for equipment operating at 600 volts, nominal, or less to ground and likely to

require examination, adjustment, servicing, or maintenance while energized shall comply with

the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this

Code.

For equipment rated 1200 amperes or more and over 6 feet wide that contains overcurrent

devices, switching devices, or control devices there shall be an entrance to and egress from

each end of the working space. These entrances shall be at least 24 inches wide and 6 1/2 feet

high. 110.26(C)2 Where the location permits a continuous and unobstructed way of exit travel,

or where the depth of the working space is twice that required by 110.26(A)(1), a single

entrance shall be permitted. 110.26(C)(2) a & b. In all cases where live parts are normally

exposed on switchboards, panelboards, or motor control centers, that may require servicing

while energized, the depth of the workspace in front shall not be less than 3 feet. Table

110.26(A)

Illumination shall be provided for all working spaces about service equipment,

switchboards, switchgear, panelboards, or motor control centers installed indoors and

shall not be controlled by automatic means only. 110.26(D)


The minimum headroom of working spaces about service equipment, switchboards,

panelboards, or motor control centers shall be 2.0 m (61/2 ft). 110.26(E)

Equipment with exposed live parts operating at over 50 volts shall be guarded by one of the

following: 110.27(A)

(1) A room or vault accessible only to qualified persons.

(2) Suitable permanent, substantial partitions or screens high enough to permit only qualified persons.

(3) Located on a suitable balcony, gallery or platform elevated and arranged so as to

exclude unqualified persons.

(4) By elevation above the floor or other working surface of 8 feet for 50 to 300 volts

and 8.5 feet for 301 to 600 volts.

Guards or enclosures shall be so arranged and be of sufficient strength to protect from physical damage. 110.27(B)

Entrances to rooms and other guarded locations that contain exposed live parts shall be

marked with conspicuous warning signs forbidding unqualified persons to enter. 110.27 (C)

All equipment producing arcs and sparks shall be enclosed and isolated from combustible material. (110.18)

All equipment shall be marked with manufacturer’s name, trademark or other descriptive

marking, identifying the organization responsible for the product, voltage, current, wattage,

or other ratings required elsewhere in the Code. (110.21)

All disconnecting means for feeders or branch circuits shall be identified. (110.22)

APPLICATION:

If time will allow, let the class answer questions on the worksheet.




INTRODUCTION TO THE NATIONAL ELECTRIC CODE ARTICLE 110 LEVEL I

WORKSHEET

1. Equipment must be installed and used:

a. according to code only

b. according to listing and labeling instructions of the equipment and the

installation requirements of the Code.

c. to meet the needs of the inspector.

d. to meet the needs of the owner.

2. Equipment can be mounted by all of the following except:

a. toggle bolts

b. lead anchors

c. wood screws into wood framing members d. wooden plugs driven into masonry

3. The largest wire that can be connected by wire binding screws is:

a. #14

b. #12

c. #10

d. #8

4. The minimum width of the working space about equipment required to be serviced while energized is:

a. 30 inches

b. 36 inches

c. 48 inches

d. not specified in the Code

5. In all cases work space shall permit a panel door to swing to which of the following degrees?

a. 40 b. 45

c. 75 d. 90


6. The working clearance from a sheetrock wall opposite a 120/240 volt panel is which of the following in inches?

a. 30

b. 36

c. 48

d. 60

7. Illumination is required for service equipment located indoors in:

a. dwelling units

b. commercial buildings

c. dwelling units with services rated over 200 amperes

d. all of the above

8. The minimum height of headroom for the workspace in front of a 200 ampere service panel in an office building is which of the following?

a. 6 1/4 feet

b. 6 1/2 feet

c. 7 feet

d. 8 feet

9. Termination provisions for equipment rated 100 amperes or less shall be considered to have a temperature rating of which of the following unless the equipment is marked otherwise.

a. 60° C

b. 75°C

c. 90°C

d. 40°C

10. Dissimilar metals shall not be intermixed within a connector unless the device is?

a. insulated for the purpose.

b. identified for the purpose.

c. encapsulated for the purpose.

d. isolated for the purpose.


11. On a 4-wire, delta-connected secondary where the midpoint of one phase is grounded to

supply lighting and similar loads, the phase conductor having the higher voltage to ground

shall be identified by tagging or other effective means or by an outer finish that is which of the

following colors?

a. red

b. brown

c. white

d. orange


INTRODUCTION TO THE NATIONAL ELECTRIC CODE ARTICLE 110

LEVEL I

ANSWER KEY

1. b [110.3(B)]

2. d [110.13(A)]

3. c [110.14(A)]

4. a [110.26(A)(2)]

5. d [110.26(A)(2)]

6. b Table [110.26(A)(1)] 7. d [110.26(D)]

8. b 110.26(A)(3)

9. a [110.14(C)(1)] 10. b [110.14]

11. d [110.15]


USE AND IDENTIFICATION OF GROUNDED CONDUCTORS

ARTICLE 200

LEVEL I

OBJECTIVES:

Each student should become familiar with:

1. The identification of grounded conductors.

2. The requirements for grounded conductors in premises wiring systems

3. The identification of terminals used for the connection of grounded conductors.

MATERIALS NEEDED:

Samples of white colored conductors, a three wire grounded receptacle, and a screw shell lamp holder. (Optional)

INTRODUCTION:

When working in an electrical system, it is very important that the electrician know which

conductor is the grounded conductor. The grounded conductor is a system or circuit

conductor that is intentionally grounded. On some systems the grounded conductor is also

known as the “neutral” conductor. It has to be easily distinguished from the ungrounded

conductors. Article 200 gives the requirements of identifying grounded conductors and

terminals.


200.2

(A)With the few exceptions of section 200.2, all premises wiring systems shall have a

grounded conductor. 200.2 (B) The continuity of a grounded conductor shall not depend on a

connection to a metallic enclosure, raceway, or cable armor.

200.3

Premises wiring shall not be electrically connected to a supply system unless the latter

contains, for any grounded conductor of the interior system, a corresponding conductor which is at the time of installation by a gray marking at its terminations grounded.


200.6

There are specific ways to identify grounded conductors of various sizes. Generally, an

insulated grounded conductor of No. 6 or smaller shall be identified by a Continuous white

or gray outer finish or by three continuous white or gray stripes on other than green

insulation along its entire length.

Insulated grounded conductors larger than No. 6 can be identified as the No. 6 and

smaller or, at the time of installation by a distinctive white marking at its terminations.

Cover the exceptions noted in Section 200.6 (B).

Note: 200.6(A) requires grounded conductors that included 6 AWG to be identified by a

continuous white, gray color, or by three continuous white stripes on other than green

insulation along its entire length. A black #12 AWG grounded conductor could not be marked

with tape at the terminations.

200.7

(A) A conductor identified as just described shall be used only for the grounded conductor unless otherwise permitted in 200.7 (B) and (C).

200.7

(C) The use of insulation that is white or gray or that has three continuous white or gray

stripes for other than a grounded conductor for circuits of 50 volts or more shall be

permitted for an ungrounded conductor, switch loops and flexible cords for appliances

where re-identified.

200.9

The identification of terminals to which a grounded conductor is to be connected

shall be substantially white in color. The identification of other terminals shall be of a readily

distinguishable different color.

200.10

This section covers the identification of terminals for devices, receptacles, plugs and

appliances.

APPLICATION:


CHECKING AND FOLLOW UP:




ARTICLE 200

LEVEL I

1. All premises wiring systems shall have a grounded conductor that is identified in

accordance with which of the following section(s)?

a. 210.6 b. 200.6

c. 215.6 d. 310.16

2. Without exception the insulated grounded conductor, in a multi conductor cable, shall be

identified by a continuous white or gray outer finish or by three continuous white stripes

on other than which color insulation along its entire length?

a. blue b. red

c. green

d. white

3. An insulated grounded conductor larger than No. 6 may be identified at the time of

installation by all the following EXCEPT for which of the following?

a. by a continuous white finish. b. by a continuous gray finish.

c. by a continuous green finish.

d. by making a distinctive white or gray marking at it’s terminations, with the

marking encircling the conductor’s insulation.

4. The grounded conductor in a flexible cord may be identified by which of the following means?

a. Tinned Conductors

b. Tracer in Braid. c. both of the above

d. neither of the above

5. The continuity of a grounded conductor shall not depend on a connection to a ___________ .

a. metallic enclosure

b. raceway

c. cable armor

d. all of the above


6. The identification of terminals to which a grounded conductor is to be connected

a shall be substantially white in color

b. shall be identified with the letter W

c. shall be identified with the word White.

d. shall be any of the above

7. A white wire, in a multiconductor, cable used as an ungrounded conductor, shall be

permanently re-identified by which of the following?

a. I. painting

b. II. other effective means at its terminations and other visible and accessible locations.

c. Either I or II

d. Neither I nor II

8. For devices with screw shells, which of the following shall the grounded conductor be

connected to?

a. the screw shell

b. the base of the shell

c. the white switch terminal

d. the ungrounded terminal

9. No grounded conductors shall be attached to any terminal or lead so as to reverse which

of the following?

a. intrinsic connection

b. linear load

c. line voltage

d. designated polarity

10. Where grounded conductors of different systems are installed in the same

raceway, cable, box, auxiliary gutter, or other type of enclosure, the grounded

conductors may be marked in which of the following approved manners?

a. gray, white

b. white, gray with green stripes

c. green, white

d. white, white with green stripes



ARTICLE 200

LEVEL I

ANSWER KEY

1. b. 200.6 200.6

2. c. green 200.6 (E) 3. c. 200.6b

4. c. 200.6 (400.22(B)&(E)

5. d. 200.2(B) 6. a. 200.9

7. c. 200.7 (C)(1)

8. a. 200.10(C) 9. d. polarity 200.11

10. a. 200.6 (D)


BRANCH CIRCUITS ARTICLE 210 LEVEL I

OBJECTIVES:

Each student should become familiar with the:

1. General provisions of branch circuits

2. Branch circuit rating provisions

3. Guidelines for required outlets of branched circuits

INTRODUCTION:

The branch circuit refers to the circuit conductors between the final overcurrent device

protecting the circuit and the outlets. For definitions of various types of branch circuits, see

Article 100.

210.1

This Article covers branch circuits except for branch circuits which supply only motor loads, which

are covered in Article 430. This Article applies to branch circuits with combination loads. Also, branch circuits for electrolytic cells are covered in Section 668.3(C).

210.2

There are many applicable provisions of other articles of this code which apply to branch

circuits as well as this Article. Section 210.2 contains a list of these other articles.

210.3

The maximum permitted ampere rating or setting of the overcurrent device shall classify branch

circuits. If larger conductors are used for any reason, the overcurrent device shall determine the

circuit classification. The rating for other than individual branch circuits shall be 15, 20, 30, 40, and

50 amperes. Exception: Multioutlet branch circuits greater than 50 amperes permitted in industrial

premises under certain conditions. This was added in the 1984 Code so industries could have a

welder circuit, over 50 amperes at several locations, at one time.

210.4(A)

A multiwire branch circuit may be considered as multiple circuits and all conductors of a multiwire

circuit shall originate from the same panelboard or similar distribution equipment.


210.4(B)

All multiwire branch circuits will be required to be provided with means that will

simultaneously disconnect all ungrounded conductors at the point where the branch circuit

originates.

210.4(C)

Multiwire branch circuits shall supply only line to neutral loads. Exception 1: Only one utilization equipment. Exception 2: Where all ungrounded conductors of the multiwire branch circuit are opened simultaneously.

210.4 (D)

All conductors of a multiwire circuit shall be grouped at least once within the

panelboard. As outlined in the exception this is not a requirement for cables or

raceways that are unique to the circuit and makes the grouping obvious or are identified by numbers at the terminals with the appropriate circuit number.

210.5(A)

The color code for branch circuit grounded conductors shall be in accordance with 200.6

210.5(C)

Where the premises wiring system has branch circuits supplied from more than one

nominal voltage system, each ungrounded conductor of a branch circuit, where accessible,

shall be identified by phase or line and system at all terminations, connections, and splice

points.

210.8(A)

Dwelling Units – explain GFCI protection for 125 volt 15 and 20 ampere receptacles Go over

specific locations in 210.8(A)(1) – (10). Note: These requirements are only for dwelling units.

See definition of “dwelling unit” in Article 100. Note: 210.8(A)3 for NC Amendments.

210.8(B)

Note: Eight locations for “other than dwelling units” Other articles require GFCI protection: 555.19(B)(1), 511.12.

210.19

Branch circuit conductors shall have an ampacity of not less than the maximum load to be

served. See Section 210.19 for details on multi-outlet branch circuits, cooking appliances, etc.


210.20

Overcurrent devices having a rating or setting within given specifications of the Code shall

protect branch circuit conductors and equipment.

210.21

Outlet devices shall have an ampere rating not less than the load to be served. See Section 210.21 A and B. Show and discuss tables 210.21(B)(2) and (B)(3).

210.23

The maximum load shall not exceed the rating of the branch circuit or other specified

conditions of the code. Discuss permissible loads for specific branch circuits located in

sections 210.23(A), through 210.23(D). See Table 210.24 for a summary of branch circuit

requirements.

210 Part III

Whenever flexible cords are used, a receptacle shall be installed unless the cords are

permanently connected, as permitted in 400.7. Appliance outlets such as for a washing

machine shall be installed 6 feet from the intended location of the appliance. Receptacle

outlets shall be installed as specified in Sections 210.52 – 210.64. A cord connector that is

supplied by a permanently connected cord pendant shall be considered a receptacle outlet.

Discuss the general provisions for receptacle outlets for:

1. dwelling units

2. guest rooms

3. show rooms

4. rooftop heating, air conditioning and refrigeration equipment

Review required lighting outlets for dwelling units and guest rooms in Section

210.70.

APPLICATION:



If time allows, correct the worksheets and discuss the results. Insure students

understand Article 210.


BRANCH CIRCUITS ARTICLE 210 LEVEL I WORKSHEET

1. Branch circuits shall be rated by which of the following?

A. Maximum permitted ampere rating.

B. Maximum setting of the overcurrent device.

C. Both of the above

D. Neither of the above

2. Which of the following statements about the color codes for branch circuits is/are

correct?

A. The grounded conductor of a branch circuit shall be identified by a continuous white

or gray color.

B. The equipment grounding conductor of a branch circuit shall be a continuous

yellow color.

a. A only b. B only

c. Both A and B d. Neither A or B

3. Under certain conditions, a receptacle may be mounted not more than which

of the following inches below a kitchen countertop.

a. 16 inches

b. 10 inches

c. 8 inches d. 12 inches

4. In places, other than dwelling units, GFCI protection shall be installed in all

the locations below with the exception of?

a. Bathrooms b. Commercial and institutional kitchens

c. Outdoors in public places

d. At a convenience store behind the cash register


5. In dwelling units all of the following require GFCI protection Except?

a. A single receptacle in the garage for a central vacuum

b. A garage door opener

c. A single receptacle in the basement for a permanently installed fire alarm or

burglar alarm

d. All of the above

6. Branch circuit conductors shall have an ampacity not less than which of the following?

a. The minimum load to be served.

b. The maximum load to be served.

c. The total load to be served.

d. The expected load to be served.

7. The rating of a branch circuit supplying only store lighting shall not be less than which of the following?

a. 100 percent of the rating of the continuous load.

b. 125 percent of the rating of the noncontinuous load.

c. 300 percent of the starting load.

d. 125 percent of the continuous load.

8. Branch circuit conductors and equipment shall be protected by an overcurrent protective

device having some noncontinuous load plus some continuous load shall have

overcurrent protection at which of the following?

a. 100 percent of the continuous and 125 percent of the noncontinuous.

b. 125 percent of the continuous and 100 percent of the noncontinuous.

c. 150 percent of both loads.

d. 250 percent of all loads.

9. Which of the following statements is/are permissible loads for branch circuits?

I- 15 or 20-ampere to supply to supply lighting units or other utilization

equipment

II- 40 and 50-ampere to supply cooking equipment and other utilization

equipment.

a. I only c. both I and II

b. II only d. neither I nor II


10. Most rooms in dwelling units shall have receptacles installed so that no point along the

floor is more than which of the following?

a. 12 feet from an outlet.

b. 8 feet from an outlet.

c. 3 feet from an outlet. d. 6 feet from an outlet.

11. At least one wall receptacle shall be installed in the bathroom of all dwellings at no more

than which of the following distance?

a. Within three feet of the basin. b. Within three feet of the countertop.

c. Within three feet of the cabinet.

d. Within three feet of the GFCI.

12. A 125-volt, single-phase, 15- or 20-ampere-rated receptacle outlet shall be installed at an accessible location for the servicing of heating, air-conditioning, and refrigeration equipment. The receptacle shall be located on the same level and within _____________ of the heating, air-conditioning, and refrigeration equipment.

a. 25 feet. b. In sight of c.50 feet d. none of the above

13. At the front and back of a two-family dwelling an outdoor outlet shall be

provided in which of the following manners?

a. At the point of exit, but not greater than 6 feet above grade. b. Accessible from grade level and not more than 6 1/2 feet above grade level.

c. Accessible from the exit and not more than 3 feet above grade level.

d. Accessible from the HVAC system and not more than 6 feet away.

14. Appliance outlets installed in a dwelling unit for specific appliances, such as laundry equipment, shall be installed within which of the following?

a. Within 3 feet of the intended location of the appliance. b. Within 6 feet of the intended appliance.

c. Within 12 feet of the intended appliance.

d. Within 2 ft. 6 inches of the intended appliance.


15. Balconies, decks and porches that are attached to the dwelling unit and are accessible from

inside the dwelling unit shall have at least one receptacle outlet installed within the

perimeter of the balcony, deck, or porch at not more than______ above the balcony, deck or

porch walking surface.

a. 18ft

b. 6.5ft

c. 3ft

d. 2ft


BRANCH CIRCUITS ARTICLE 210 Level 1 ANSWER KEY

1.

2.

3.

3.

C

a

d

210.3

210.5

210.52 (C) (5) Ex to (5) 4.

d 210.8(B) Ex.

5. c 210.8(A)(1-8)

6. b, maximum 210.19(A)(1)

7. d, 125% 210.19 (A)(1) 8. b 210.20(A)(1) 9. d 210.22

10. d, six 210.52(A)(1)

11. a, basin 210.52(D)

12. a 210.63

13. b 210.52(E)

14.

15.

b

b

210.50 (C)

210.52 (E)(3)


FEEDERS ARTICLE 215

LEVEL I

OBJECTIVE:

Each student should become acquainted with the installation requirements and minimum size and

ampacity of conductors for feeders supplying branch circuit loads.

INTRODUCTION:

The word “feeder” refers to all circuit conductors between the service equipment or the source of

a separately derived system and the final branch circuit overcurrent device.

The branch circuit loads are computed in accordance with Article 220.


Discuss and give examples of the following: 215.2 Minimum Rating and Size of Feeder Conductors. (A) Ampacity for feeder conductors are computed by Part III, IV and V of Article 220. (A)(2) Feeder conductors shall be sized to carry not be less than the load to be served: 215.3 Overcurrent Protection: See part I of Article 240 215.4 Feeders with Common Neutral Conductor.

(A) Up to 3 sets of 3-wire feeders or 2 sets of 4-wire or 5-wire feeders shall be permitted to contain a common neutral.

(B) Feeders with a common neutral must be enclosed in the same raceway or enclosure when the raceway or enclosure is metal. 215.6 Feeder and Grounding Means

215.9 Ground Fault Protection for Personnel: Explain the principle and emphasize why and where it is most likely to be used.

APPLICATION:

If time will allow, let the class answer questions on the worksheet. CHECKING

AND FOLLOW-UP:



FEEDERS ARTICLE 215 LEVEL I

WORKSHEET

1. Feeder conductors shall have an ampacity not lower than required to supply the load as

computed in which of the following parts of Article 220?

a. Part III, IV and V.

b. Part II, III and IV.

c. Part III and V.

d. Part V.

2. Feeders shall be protected against overcurrent in accordance with provisions of?

a. Part I of Article 240.

b. Part II of Article 220

c. Part III of Article 210

d. Part I of Article 310

3. Feeders containing a common neutral shall be permitted to supply which of the

following?

a. Two or three sets of 3 wire feeders.

b. Two sets of 4 wire feeders c. Two sets of 5 wire feeders.

d. All of the above

4. A diagram showing feeder details shall be provided prior to the installation of the

feeders in which of the following circumstances?

a. If required by the authority having jurisdiction.

b. If required by the design professional. c. If required by the Administration and Enforcement Code.

d. If required by the Department of Insurance.


5. Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall provide a grounding means in accordance with which of the following?

a. The provisions of 250.52

b. The provisions of 250.134

c. The provisions of 220.14

d. The provisions of 210.52

6. Feeders supplying 15 and 20 ampere receptacle branch circuits may be protected by which of the following in lieu of regular GFCI outlets.

a. Ground fault circuit interrupter type 120/240 volt breakers.

b. Intrinsically safe systems breakers.

e. HID type circuit breakers.

f. SWD type circuit breakers.

7. The minimum size of the feeder circuit grounded conductor shall not be smaller than the provisions given in which of the following?

a. Table 250.66 for the equipment grounding conductor.

b. Table 250.122 for the equipment ground.

c. Table 310.16 for the ungrounded conductor size.

d. Table 250.52 for the maximum size fused conductor.

8.Where a feeder supplies branch circuits in which equipment grounding conductors are

required, the feeder shall include or provide which of the following in accordance with the

provisions of 250.134, to which the equipment grounding conductors of the branch circuits

shall be connected.

a. a grounding electrode conductor

b. a neutral conductor c. a common conductor

d. an equipment grounding conductor


FEEDERS

ARTICLE 215

LEVEL I

ANSWER KEY

1. a. Parts III, IV and V Article 215.2 (A)(1) 2. a. 215.3

3. d. all of the above 215.4(A)

4. a. 215.5

5. b. 215.6

6. a. 215.9 7. b. 215.2 (A)(2)

8. d. 215.6


BRANCH CIRCUIT, FEEDER, AND SERVICE CALCULATIONS ARTICLE 220 LEVEL I

OBJECTIVE:

Each student should become acquainted with the requirements for determining the number of

branch circuits required and for computing branch circuit, feeder, and service loads.

INTRODUCTION:

This lesson introduces the student to basic electrical formulas and methods used to determine

sizes of branch circuits, feeders, and services. Emphasis on the standard method and optional

method calculations will be used.


The relationship of amperes, ohms and volts can be expressed by the following formula

(known as Ohm’s Law).

I = E

R

I = the intensity of current flow in amperes

E = the electromotive force in volts R =

the resistance in ohms

Ohm’s Law can be modified to solve practical problems involving a house wiring circuit.

W = E x I

I = the intensity of current flow in amperes

E = the electromotive force in volts

W= the unit of power in watts

Thus, if we know that a lamp is 120 volts and 200 watts, the amperes flowing through it

can be found.

I = W/E = 200 watts = 1.66 amperes

120 volts


When three-phase loads are calculated, the total wattage or volt-amperage is divided by phase-

to-phase voltage times 1.732

The following values may be used:

For 208 volts x 1.732, use 360 volts For

230 volts x 1.732, use 398 volts

For 240 volts x 1.732, use 416 volts

For 480 volts x 1.732, use 831 volts

Lead the class through a calculation of a single-family dwelling using the standard method

and the optional method.

NEC references should be pointed out in each step of the calculation.

Example: Standard Method (See examples - Annex D)

Given a 2,800 square foot dwelling with 120/240 volt single-phase service with the

following loads:

disposal @120 volts = 800 VA

compactor @120 volts = 600 VA

dishwasher @120 volts = 1,200 VA

attic fan @120 volts = 1,080 VA

clothes dryer @120/240 volts = 5,000 VA

range @120/240 volts = 12,000 VA

water heater @240 volts = 4,500 VA

electric space heater @240 volts = 15,000 VA

air conditioner @240 volts = 6,000 VA

The problem can be broken down into the following parts:

1. Find the General Lighting Load. Use Table 220.12 to determine floor area. 220.12 says that the floor area for each floor shall be computed from outside dimension of the building but not including open porches, garages, or unused or unfinished spaces not adaptable for future use.

2,800 sq. ft. x 3 VA = 8,400 VA

Section 210.11(C)(1)requires two or more 20-ampere small appliance branch circuits for all receptacles in the kitchen, pantry, breakfast room, and dining room in a dwelling and


Section 220.52 requires that each 2-wire small appliance branch circuit be computed at 1,500 VA. These loads may be included in the general lighting load. Small Appliance Load:

2 @ 1,500 VA = 3,000 VA Section 210.11(C)(2) requires at least one additional 20 ampere branch circuit for the laundry and 220.52(B) requires each 2-wire laundry branch circuit be computed at 1,500 VA. This may be included in the general lighting load.

Laundry Load: 1 @ 1,500 VA = 1,500 V

gen. lighting 8,400VA, + small appl. 3,000VA + laundry 1,500VA =12,900VA Minimum number of Branch Circuits Required General Lighting Load: I=E/R =

8,400VA/120VLTS = 70 AMPS For 15 amp circuit: 70 ampere/15 amp circuit = 4.66 or 5 circuits For 20 amp circuit: 70 ampere/20 amp circuit= 3.5 or 4 circuits

For General Lighting: 5.15 ampere 2 wire or 4.20 ampere 2 wire circuits

For small Appliances: 2.20 ampere 2 wire circuits

For Laundry: 1.20 ampere 2 wire circuits

For Bathroom Outlets: 1.20 ampere 2 wire circuit (no additional load)

Use Table 220.42 for demand factors, 3,000 VA @ 100% = 3,000 VA 3,001 to 120,000 @ 35% 12,900 to 3,000 = 9,900 @ 35% = 3,465 VA General Lighting Load: 3,000 VA + 3,465 VA = 6,465 VA

2. Find the Cooking Equipment Load:

Review Table 220.55 explaining the use of columns A, B, and C and the notes to the table.

Demand factor for one 12 KW range from Table

220.55 Column A: 12 KW = 8,000 VA Range Load = 8,000 VA

3. Find the Dryer Load:

Use Table 220.54

The load for household electric clothes dryers in a dwelling unit shall be 5,000 watts (VA) or the nameplate rating whichever is greater.


Demand factor for one 5KW dryer from Table

220.54 5,000 @ 100% = 5,000 VA Dryer Load = 5,000 VA

4. Find the Fixed Appliance Loads:

Section 220.53 allows a demand factor of 75% to the nameplate-rating load of four or more appliances fastened in place or a feeder or service entrance for a residential dwelling.

Disposal = 800 VA Compactor = 600 VA Dishwasher = 1,200 VA Attic Fan = 1,080 VA

Water Heater = 4,500 VA

TOTAL = 8,180 VA Demand factor for 8,180 VA x 75% = 6,135 VA Fixed appliance load = 6,135 VA

5. Find the Heating and/or Air Conditioning Load: Section 220.60 allows omitting the smaller of two dissimilar loads where it is unlikely they will be in use simultaneously.

Electric space heating @ 240 volts = 15 KW Air conditioning @ 240 volts = 6 KW Air conditioning load is smaller; therefore, it may be omitted

Section 220.51 requires that fixed electric space heating loads be computed at 100% of the total connected load. Note and explain exception to Section 220.15.

Electric Space heating: 15,000 VA x 100% = 15,000 VA

6. Find Largest Motor Load: Section 220.50 requires motor load to be computed in accordance with Sections 430.24, 430.25, and 430.26. Section 430.25 gives the requirement for motors and combination loads (lighting and appliance loads). Sections 220.50 and 430.22 require that 25% of the motor full load current be added to the total calculation for the dwelling unit. Largest motor is the attic fan @ 1,080 VA: 1,080 x 25% = 270 VA

7. Find the Service Load: The service load is found by adding the loads found in the previous steps and dividing by the applied voltage.

1. General Lighting Load = 6,465 VA

2. Range Load = 8,000 VA

3. Dryer Load = 5,000 VA

4. Fixed Appliance Load = 6,135 VA

5. Heating Load = 15,000 VA

6. Largest Motor Load = 270 VA

TOTAL = 40,870 VA I = W/E = 40,870 VA = 170amps Service Load


240 Volts

8. Find the Neutral Load:

Section 220.61 requires that the feeder neutral load be the maximum unbalanced load between the neutral and any one ungrounded conductor. A further demand factor of 70% is permitted for that portion of the unbalance load in excess of 200 amperes except when that load consists of electric-discharge lighting data processing supplied from a 4-wire, wye connected 3 phase system.

General Lighting Load from step 1 6,465 VA

Range Load from step 2 8,000 VA x 70% = 5,600 VA 5,600 VA

*Section 220.61 allows the maximum unbalanced load to be considered as 70% of the load on the ungrounded conductors.

Dryer Load from step 3 5,000 VA x 70% = 3,500 VA 3,500 VA

*Section 220.54 allows the maximum unbalanced load to be considered as 70% of the load on the ungrounded conductors. Fixed appliance load using only those that are 120 volt loads from step 4:

Disposal 800 VA

Compactor 600 VA

Dishwasher 1,200 VA

Attic Fan 1,080 VA

TOTAL:

Apply demand factors of Table 220.42:

3,680 VA

3,680 VA x 75% Largest

Motor Load from step 6

2,760 VA

Attic fan = 1,080 VA x 25% = 270 VA

18,595 VA

I = W/E = 18,595 VA = 77.48 amperes Neutral Load = 77 amps

240 Volts

Example #1: Optional Method

Section 220.82 permits the feeder and service load for a dwelling unit having the total

connected load served by a single 3-wire 120/240 volt or 208Y/120 volt set of service-

entrance or feeder conductor with an ampacity of 100 or greater computed in


accordance with an optional method instead of the method specified in Part II of this

article.

There are two loads that are calculated when applying the optional method: Use

220.82. Other loads and remainder of other loads.

1,500 VA for each 20 ampere small appliance branch circuit:

1,500 VA x 2 = 3,000 VA

1,500 VA for each 20 ampere laundry branch circuit:

1,500 VA = 1,500 VA

Note: No load is added for bathroom outlets 3

VA per sq. ft x 2,800 sf = 8,400 VA

Nameplate rating of all fastened in place appliances, ranges, wall-mounted ovens, and

counter mounted cooking tops.

Disposal 800 VA

Compactor 600 VA

Dishwasher 1,200 VA

Attic Fan 1,080 VA

Clothes Dryer 5,000 VA

Range 12,000 VA

Water Heater 4,500 VA

2 Small Appliance Circuits 3,000 VA

1 Laundry Circuit 1,500 VA

TOTAL:

Apply demand factors from 220.82(B)

38,080 VA

Total Load 38,080 VA

Less First: 10,000 VA @ 100% - 10,000 VA

28,080 VA

Next: 28,080 VA @ 40% = 11,232 VA

Next: Add back first 10,000 VA + 10,000 VA

21,232 VA Heating

or Air Conditioning Load:

The smaller of the heating or air conditioning load is dropped after applying the demands as

specified in 220.82(C). Compare Heating and Air Conditioning


Central Electric Space Heating:

15,000 VA x 65% = 9,750 VA Air

Conditioning:

6,000 x 100% = 6,000 VA

Electric Space Heating is largest: 9,750 VA

21,232 + 9,750 = 30,292 VA

I = W/E = 30,292 VA = 129.09 amperes Service Load

240 volts

Service Load = 129 amperes

The Neutral Load is permitted to be calculated as determined by Section 220.61; therefore, the Neutral Load is the same as calculated in the standard method. Example #2: Optional Method

Section 220.82 permits the feeder and service load for a dwelling unit having the total connected load served by a single 3-wire 120/240 volt or 208Y/120 volt set of service-entrance or feeder conductor with an ampacity of 100 or greater computed in accordance with Section 220.82 instead of the method specified in Part II of this article. There are two loads that are calculated when applying the optional method: Use

220.82. Other loads and remainder of other loads.

1,500 VA for each 20 ampere small appliance branch circuit:

1,500 VA x 2 = 3,000 VA

1,500 VA for each 20 ampere laundry branch circuit:

1,500 VA = 1,500 VA

Note: No load is added for bathroom outlets

3 VA per sq. ft x 2,800 sq. ft. = 8,400 VA


Nameplate rating of all fastened in place appliances, ranges, wall-mounted ovens, and counter mounted cooking tops.

Disposal 800 VA

Compactor 600 VA

Dishwasher 1,200 VA

Attic Fan 1,080 VA

Clothes Dryer 5,000 VA

Range 12,000 VA

Water Heater 4,500 VA

TOTAL: 25,180 VA

26,500 VA 38,080 VA

Apply demand factors from 220.30(B)

First: 10,000 VA @ 100% = 10,000 VA

Next: 29,400 VA @ 40% = 11,760 VA

21,760 VA

Heat Pump Compressor with supplemental heat operating at the same time:

See Section 220.82(C)

Compare Heating and Air Conditioning

Supplemental heat: 15,000 VA x 100% = 15,000 VA

Heat Pump Compressor: 6,000 x 65% = 3,900 VA

I = W/E = 40,660 VA = 169.4 amps 240 Volts

Service Load = 169 amperes APPLICATION:

If time allows, let the class time to answer questions on the worksheet.




BRANCH CIRCUIT, FEEDER, AND SERVICE CALCULATIONS ARTICLE 220 LEVEL I WORKSHEET

1. Given a 3,200 sq. ft. dwelling with 120/240V, single phase. Find the minimum lighting load demand for the General Lighting.

a. 14,100 VA

b. 4,935 VA

c. 9,600 VA

d. 6,885 VA

2. What is the load for one 9-KW range?

a. 9 KW

b. 8 KW

c. 6.3 KW

d. 12 KW

3. How many two wire branch-circuits are required in an 1,800 sq. ft. dwelling with three bathrooms? The dwelling is supplied by a 120/240V, single phase service.

a. 3-15 ampere branch circuit and 4-20 ampere branch circuits

b. 5-20 ampere branch circuit

c. 4-15 ampere branch circuit and 2-20 ampere branch circuits

d. 6-15 ampere branch circuits

4. Given a 2,800 sq. ft. dwelling with 120/240V, single phase service and the following

loads:

Range = 12,000 VA

Dryer = 5,000 VA

Water Heater = 4,500 VA

Dishwasher = 1,200 VA

15 KW Central Heating = 15,000 VA

Air Conditioning = 6,000 VA

Find the Service Load using the Standard Calculation. a. 200

amperes

b. 100 amperes

c. 167 amperes

d. 130 amperes


5. Given the same information as in problem #4, find the Neutral Load.

a. 100 amperes

b. 69.8 amperes

c. 116.9 amperes

d. 65 amperes

6. Given the same information as in Problem 4, compute the service load using the

Optional Calculation.

a. 189 amperes

b. 150 amperes

c. 125 amperes

d. 169 amperes

7. Using the optional method of calculation, determine the load that would be added to

the service for a 3 HP, 240, volt, single phase heat pump compressor with supplemental

heating rated at 15 KW. The control circuitry is not interlocked to prevent the heat

pump compressor and the supplemental heating from operating at the same time.

a. 17 amperes

b. 19.6 amperes

c. 57.63 amperes

d. 62.5 amperes

8. Proper calculations for Electrified Truck Spaces are found in:

a. Article 220

b. Article 626

c. Article 511

d. Article 551


BRANCH CIRCUIT, FEEDER, AND SERVICE CALCULATIONS

ARTICLE 220 LEVEL I

ANSWER KEY

1. d, 6,885 VA

({[(3200 x 3) + 3,000 + 1,500] - 3,000} x 35%) + 3,000 = 6,885

2. b, 8 KW (Table 220.55)

3. a, 3-15 ampere branch circuit and 4.20 ampere branch circuits

([1,800 sq. ft. x 3 VA per sq. ft.]/120)/15 = 3.15 ampere branch circuit plus 4-20 amp

4. c, 167 amperes

2,800 x 3 = 8,400

4,500

12,900 - 3,000 = 9,900

9,900 x 35% = 3,465 + 3,000 = 6,465 General Lighting

8,000 Range

5,000 Dryer

4,500 Water Heater

1,200 Dishwasher

15,000 Heat

40,165 TOTAL 40,165/240 = 167 amps

5. b, 69.8 amperes

6,465 General Lighting

8,000 x 70% = 5,600 Range

5,000 x 70% = 3,500 Dryer

1,200 Dishwasher

16,765 16,765/240 = 69.8 amps

6. c, 125 amperes

HEAT 15,000 x .65 = 9750 VA (AC = 6,000 VA) HEAT is larger

Other Load 2800 x 3 = 8,400 VA Small Appliances

= 3,000

Laundry = 1,500

Range = 12,000

Dryer = 5,000

Water Heater = 4,500

Dishwasher = 1,200

35,600

(35,600 . 10,000) x .40 = 10,240

10,240 + 10,000 = 20,240

20,240 + 9,750 = 29,990

29,990/240 = 124.95


7. c

240 volts x 17 amperes = 4,080 VA @ (100%)

.65 x 15,000 = + 9,750 VA

13,830 VA

13,830/240 = 57.63 amperes 220.82 (C), Table 430.248

8. b. Article 626


ARTICLE 225 LEVEL I

OBJECTIVE:

Each student should become familiar with electrical equipment and wiring located on the outside

of buildings, structures or poles on the premises served.

INTRODUCTION:

Circuits run on the exterior of buildings or between buildings and or other structures are

considered outside branch-circuits or feeder. For example, circuits supplying parking lot lighting are

cover by Article 225. There are many other Articles in the Code that deal with outside circuits and

they should also be consulted when the need arises. One such example is the wiring around a

swimming pool.


In order to determine the load on outdoor branch circuits you should consult with Article 220.

Also, the load on outdoor feeders shall comply with Part II of Article 220.

Where open wiring on insulators is within 10 feet of buildings it shall be covered or insulated.

See Section 225.4 for different types of coverings for various situations.

See Tables 310.16 through 310.31 for information on conductor sizes. Conductor minimum sizes

for overhead conductors 600 volts, nominal or less shall be No. 10 copper or No. 8 aluminum for spans

up to 50 feet in length and No. 8 copper or No. 6 aluminum for longer spans.

Festoon lighting is a string of outdoor lights suspended between two points. For such lighting

overhead conductors shall not be smaller than No. 12. unless supported by messenger wires. See

Section 225.14 for more information on festoon lights. (225.6)

When lighting equipment is installed outdoors, the branch-circuits shall comply with Article 210

and 225.7(B-D).

The disconnecting means for branch circuits and feeder fuse shall be in accordance with Section

240.40 and overcurrent protection shall be in accordance with Section 210.20 for branch circuits and

Part I of Article 240 for feeders.

Where more than one disconnecting means is provided at structures other than dwelling

units a plaque or directory must be installed at each disconnect location.

The restrictions on wiring for outside wiring surfaces of buildings are covered in Section 225.10. When dealing with circuit entrances and exits, see the requirements listed in Section 230.52, and 54.


See Table 230.51(C) for open conductor spacing. Open conductors of different circuits

shall be separated by not less than 4 inches. For information on the separation of conductors

on poles see Section 225.14(D).

Supports over buildings, points of attachment, and means of attachment are covered in

Section 230.29, 26, and 27 respectively. Ground clearances are outlined in Section 225.18.

Conductor clearances from buildings of not over 600 volts, nominal have several

requirements. Conductors that are not adequately insulated for normal operating voltage

shall have an 8 foot vertical or diagonal clearance from a roof surface unless they meet one of

the 4 exceptions listed in Section 225.19(A). Clearances from non-bridge or non-building

structures such as signs, chimneys, etc. shall not be less than 3 feet for conductors in vertical,

diagonal or horizontal positions.

Horizontal clearances shall not be less than 3 feet for conductors. Final spans of feeders

or branch circuits to a building shall be permitted to be attached to the building if kept 3 feet

from windows, doors, porches, fire escapes or similar locations; however, when conductors

run above a window it shall be permitted to be less than 3 feet. See Section 225.19(E) for

clearances in zones for fire ladders.

Other various Articles should be consulted concerning mechanical protection and

multiconductor cables and raceways on exterior surfaces of buildings. Underground circuits

shall comply with Section 300.5.

Outdoor lampholders when attached as pendants, the connection shall be

staggered. Also, if terminals that puncture the insulation of conductors are used to make

contact, they should only be used on stranded type conductors. See Section 225.25 for

location of outdoor lamps. (225.24)

Live vegetation, such as trees may not be used to support overhead conductor spans or

other electrical equipment, except when used in accordance with Article 590 concerning

temporary wiring. (225.26) See 410.16(H) for support of outdoor lighting fixtures in trees.

APPLICATION: If time allow, let the class answer the questions on the worksheet.

CHECKING AND FOLLOW-UP: If time allows, correct the worksheets and discuss the results.


OUTSIDE BRANCH CIRCUITS AND FEEDERS ARTICLE 225 Level I

WORKSHEET

1. When without messenger wires, overhead conductors for festoon lighting shall not

be smaller than:

a. #14

b. # 12 c. #10

d. #8

2. Overhead conductors for 600 volts and less installations, up to 50 feet in length

and not supported by a messenger wire, shall be a minimum size in copper of:

a. #12

b. #8

c. #10 d. #6

3. Open conductors of a 480/277 volt overhead feeder shall have a minimum clearance over a residential driveway of:

a. 10 feet

b. 12 feet

c. 15 feet

d. 18 feet

4. Open conductors on insulators shall be insulated or covered, if they are installed within how many feet of a building or other structure?

a. 10 feet

b. 12 feet

c. 15 feet

d. 18 feet

5. Festoon lighting shall be supported by a messenger wire if the span exceeds:

a. 15 feet

b. 18 feet

c. 25 feet

d. 40 feet


6. When conductors run above a window they shall be permitted to be less than which of

the following distance from the window?

a. 3 feet

b. 6 feet

c. 5 feet

d. 10 feet

7. Which of the following may not be used to support overhead conductor spans?

a. brackets

b. live vegetation

c. poles

d. racks

8. More than one feeder or branch circuit is permitted, by the NEC, to supply a

building or structure, for all the reasons listed below with the exception of

power for which of the following?

a. convenience

b. fire pumps

c. enhanced reliability

d. optional standby systems

9. Raceways on the exterior of buildings shall be arranged to drain and shall be

raintight

in wet locations. Which of the following conduits may not be installed outside?

a. RMC b. IMC

c. FMC

d. PVC

2014 NEC Instructor Manual and Student Worksheets -- Level 1

53

OUTSIDE BRANCH CIRCUITS AND FEEDERS ARTICLE 225

LEVEL I

ANSWER KEY

1. b, #12 225.6(B)

2. c, #10 225.6(A)(1)

3. b, 12 feet 225.18(2)

4. a, 10 feet 225.4

5. d, 40 feet 225.6(B)

6. a 225.19(D)(1) exception]

7. b. live vegetation 225.26

8. a, convenience 225.30(A)

9. c. 225.22


SERVICES

ARTICLE 230

LEVEL I

OBJECTIVES:

Each student should become familiar with the NEC requirements for electrical services.

INTRODUCTION:

This lesson will cover areas relating to services including service conductors and service

equipment.


230.1

Explain "service" definitions in Article 100.

230.2

The general rule on services is that only one service is allowed per building. There are six

exceptions to this rule.

(1) Fire pumps

(2) Emergency systems

(3) Legally required standby systems

(4) Optional standby systems

(5) Parallel power production systems

(6) Systems designed for connection to multiple sources of supply for the purpose of

enhanced reliability.

230.3

Service conductors shall not pass through the interior of another building or structure.

230.6

When applying the Code to service conductors, conductors shall be considered outside the

building if under 2 inches of concrete beneath the building, within a building in a conduit

encased with 2 inches of concrete or brick, in an approved transformer vault, installed in

conduit and under not less than 18 inches of earth beneath a building or other structure, and

when RMC or IMC passes directly through the eave, but not the wall of the building.

230.7

Conductors on the load side of the main overcurrent device shall not be run in the same

raceway with service conductors.


230.9 (A)-(C)

Service conductors shall not be located within 3 feet of windows, doors, porches, fire escapes,

or similar locations. This applies only to open conductors and conductors emerging from

conduits and cable assemblies. If conductors are run above the top of a window, they will be

out of the 3 feet area. These conductors shall not be located below or obstruct the entrance.

230 Part II Service overhead conductors to a building or other structure (such as a pole) on which a meter or disconnecting means is installed shall be considered as a service drop and installed

accordingly. See definition of “service drop”.

230.22

Individual conductors shall be insulated or covered. (see exception)

230.23(A)-(C) Conductors shall be a sufficient size to carry the load served and except in the case of limited

loads of a single branch circuit, not smaller than #8 copper or #6 aluminum. In the case of a

single branch circuit, the conductors shall not be smaller than #12 or equivalent. Grounded

conductors to be sized per 250.24(C).

230.24(A)

Service conductors that pass over a roof shall have a clearance of 8 feet from any point which it

crosses with four exceptions. See 230.24(A)(1)-(5).

Area above a roof subject to pedestrian or vehicular traffic shall meet the same requirements

for conductor clearance as any other.

230.24(B)(1)-(4)

Clearance of service conductors to final grade when the voltage is less than 600 volts shall

match the following:

1. 10 feet- clearance to drip loop from final grade above sidewalks and other areas

subject to pedestrians when limited 150 volts to ground.

2. 12 feet - same as 15 feet when limited to 300 volts to ground.

3. 15 feet - over residential property, driveways and commercial areas not subject to truck

traffic.

4. 18 feet - public streets, alleys, roads, parking areas subject to truck

traffic, driveways on other than residential property, and other areas

traversed by vehicles, such as those used for cultivation, grazing, etc.

230.26

The point of attachment shall be no less than 10 feet from grade.


230.30,31,32 & 33

Underground service laterals shall meet the same requirements as overhead conductors for

insulation and size and shall be protected from physical damage.

230.40 The general rule for service entrance conductors is that each service drop shall supply only

one set. There are five exceptions. Review these exceptions.

230.41

Service entrance conductors shall be insulated. The grounded conductor may be uninsulated in

the following cases: (a) bare copper in a raceway or cable; (b) bare copper for underground

direct burial where judged suitable for soil conditions; (c) direct burial without regard to soil

conditions when part of an approved direct burial cable; and (d) aluminum or copper clad

aluminum when part of a cable assembly or identified for underground use or direct burial.

230.42b

In addition to the requirements of 230.42(A), the minimum ampacity for ungrounded

conductors for specific installations shall not be less than the rating of the service

disconnecting means specified in 230.79(A) through (D).

230.43

The wiring method for service entrance conductors shall comply with 230.43.

230.46

Unless otherwise approved by exceptions, you cannot splice service entrance conductors.

See exceptions to 230.46

230.50(B)(1)

Service entrance conductors above ground shall be protected against physical damage in

one of the following ways:

1. rigid metal conduit 2. Intermediate metal conduit

3. PVC schedule 80 4. EMT

5. Reinforced thermosetting resin conduit 6. Other approved means

230.50(B)(2) Open conductors and cables other than service entrance cables shall not be installed within

10 feet of grade level with the exception of MI and MC cable.

230.51(A) SE cables shall be supported every 30 inches and within 12 inches of a service head gooseneck or raceway connection. Open conductors exposed to weather shall be on insulating supports, racks, or brackets. If not exposed to weather on glass, on glass or porcelain knobs. Both the above shall be spaced and maintain the clearances in Table 230.51(C).


230.52

Open conductors must enter a building through open tubes slanted upward when

going through a wall. When entering through the roof, they must enter through

bushings, drip loops must be used.

230.53

Where subject to moisture, raceways shall be rain-tight and arranged to drain.

230.54

Service heads connecting to a raceway must be rain-tight. If run in cable, a service head

that is rain-tight or gooseneck must be used. In the case of a gooseneck, it must be

taped and sealed. Service heads must be located above the point of attachment or in

case this cannot be done, not more than 24 inches from service head. Conductors of

opposite polarity shall not be brought through the same hole. Drip loops shall be made

to prevent entrance of moisture.

230.56

The outer covering of the conductor in a high-leg system that has the highest voltage

to ground shall be colored orange. This high leg occurs when you have a delta

connected service and the mid-point of one phase is grounded.

230.62

Service equipment must have live parts protected from accidental contact by either

guarding or by meeting clearance requirements of Sections 110.18 and 110.27 and

have doors that can be locked.

230.66

Service equipment rated at 1000 volts or less shall be marked to identify it as

being suitable for use as service equipment.

230.70

Service disconnect means shall be located nearest the point of entrance at a readily

accessible location either inside or outside of the building. It must be marked and

identified as service equipment and must be approved for conditions. See and

handout DOI interpretation of 230.70(A).

230.71

There shall not be more than six disconnects per service or per set of service entrance

conductors. These disconnects shall be grouped in one enclosure or in up to six separate

enclosures. Two or three single pole switches or breakers capable of individual operation

used as a multiwire circuit, tied together with handle ties can be considered as one

disconnect.


230.72(C)

In multiple occupancy buildings other than ones in which electric service and maintenance are provided and accessible only to qualified persons, the service

equipment must be accessible to each occupants.

230.74 & 230.75 All ungrounded conductors must be disconnected at the same time. The neutral must also be capable of being disconnected. The most common way is by a lug on the neutral

bar.

230.77

The disconnect shall be externally operable so as not to expose the operator to live parts and shall plainly indicate whether it is open or closed.

230.79

Rating of service disconnects shall be determined by Article 220 but in no case less

than the following: (A) 15 amperes for limited loads of a single circuit, (B) 30 amperes

for two 2-wire branch circuits, (C) for single family dwelling 100 amperes 3 wire in (1)

computed loads of 10 KVA or more (2) six two wire circuits, (D) all others 60 amperes.

230.80 The combined rating of all disconnects shall not be less than that would be

required for a single disconnect.

230.82

Review this section thoroughly.

230.90

Each ungrounded service conductor shall be provided an overcurrent device in series

with that conductor for overload protection. The only exceptions to this rule would be as

provided elsewhere in the Code or for fire pumps which are capable of carrying locked

rotor current indefinitely. The neutral shall not be broken through an overcurrent device

unless, at the same time, breaking all ungrounded conductors.

230.91

Service overcurrent device shall be an integral part of the service disconnecting means

or adjacent to it.


230.92

Where service overcurrent devices are locked or are not readily accessible, branch

circuit overcurrent devices shall be on the load side in an accessible location and

shall be of a lower ampere rating than the service overcurrent device.

230.95

Solidly grounded wye structures at more than 150 volts to ground and not over 600

volts phase-to-phase shall be required to have ground fault protection at each service

disconnect means rated 1,000 amperes or more. It shall open all ungrounded

conductors with a maximum setting of 1,200 amperes with a time delay of one second

for each fault current equal to or greater than 3,000 amperes. If a combination of switch

and fuse is used, the fuse shall be capable of interrupting any current higher than the

interrupting capacity of the switch during the time the ground fault system will not

cause the switch to open.

See two exceptions. Also note that Section 230.95(c) requires performance testing.

APPLICATION: If time allows, let the class answer the questions on the worksheet.

CHECKING AND FOLLOW UP : If time allows, correct the worksheets and discuss the results.


SERVICES

ARTICLE 230

LEVEL I

WORKSHEET

1. Without exception, what is the total number of services allowed on a building?

a. 1

b. 2

c. 3

d. 4

2. Conductors shall be considered outside of the building when installed by the following:

a. rigid conduit

b. in a service entrance cable inside the building encased in 2 inches of

concrete

c. in a transformer vault conforming to Article 450 d. where run under the building without conduit

3. Service conductors shall maintain a distance from a window of?

a. 2 feet

b. 3 feet

c. 4 feet

d. 5 feet

4. Minimum size of overhead service entrance conductors is:

a. #6 copper or #6 aluminum

b. #8 copper or #6 aluminum

c. #10 copper or #8 aluminum

d. #8 copper or #8 aluminum

5. Where conductors are rated at 120/208 volts and crosses only 3 feet of roof overhang and terminates at rigid conduit, the clearance above the roof is:

a. 10 inches

b. 12 inches

c. 14 inches

d. 18 inches


6. Service drop conductors must have a vertical clearance above a public street of:

a. 10 feet b. 12 feet

b. 12 feet d. 18 feet

7. The minimum size service disconnecting means to a single family dwelling is:

a. 100 amperes b. 125 amperes

b. 125 amperes d. 200 amperes

8. Service entrance conductors can be spliced in the following:

a. metering equipment b. in a junction box going to a service disconnect

b. inside the service disconnect d. all of the above

9. Service entrances cables must be secure in accordance with which of the following?

a. 24 inches b. 30 inches

c. 36 inches d. 48 inches

10. What is the maximum number of service disconnects allowed for a service?

a. 4 b. 5

c. 6 d. 7

11. Ground fault protection is required on a solidly grounded wye system if over 150

volts to ground if the service disconnect is rated at greater than______ amperes.

a. 800 b. 1,000

c. 2,000 d. 3,000

12. More than one service is permitted on a building or structure for all the

reasons listed below with the exception of?

a. convenience b. fire pumps

c. enhanced reliability d. optional standby systems.


SERVICES

ARTICLE 230

LEVEL I

ANSWER KEY

1. a, 1 230.2

2. c, in a transformer vault conforming to Article 450 230.6

3. b, 3 feet 230.9

4. b, #8 copper or #6 aluminum 230.23(B)

5. d, 18 inches 230.24(A) exc. #3

6. d, 18 feet 230.24(B)

7. a, 100 amperes 230.79(C)

8. d 230.46

9. b, 30 inches 230.51(A)

10. c,6 230.71(A)

11. b,1000 230.95

12. a, convenience 230.2


OVERCURRENT PROTECTION

ARTICLE 240

LEVEL I

OBJECTIVES:

At the conclusion of this lesson each student should have gained:

1. an understanding that in electrical work every circuit must be provided with overcurrent

protection.

2. knowledge of the National Electrical Code 2014 standard ampere ratings.

3. knowledge about applications of overcurrent protection.

MATERIALS NEEDED:

1. Samples of different types of fuses and circuit breakers. 2. Handouts or pictures of the above.

INTRODUCTION:

In electrical work every circuit must be provided with overcurrent protection. It may be a 13,200

volt transmission line carrying 200 amperes, or it may be a 120 volt lighting circuit carrying a load of 10

amperes. Each must have some form of protective device for the possible overload of current for the

protection of both circuits and equipment.

We know that excessive current may seriously damage electrical equipment, motors, instruments,

radio receivers, etc. Fuses and circuit breakers are cheap compared with the equipment you are

protecting. When the fuse which is connected in series with equipment is blown, the circuit will open

before the excessive current damages the equipment.

It is important that you always use fuses or circuit breakers with proper current ratings. In

protecting equipment, to use fuses with too low current rating will result in unnecessary blowouts

while one with too high current rating may allow dangerously high currents to pass.

Fuses are used for protection so never jump out a fuse. Do not increase the size of a fuse unless

and until you are sure it would be in compliance with the NEC.

In this lesson we will be studying parts I through VII of Article 240 in which we are primarily concerned with the simple circuits requiring the common types of overcurrent protective devices such

as, the plug fuse, circuit breakers and cartridge fuses.



The list of Articles shown in Table 240.3 is the specific Articles that cover protection of equipment. You can refer to this list to find what Article covers the

protection of a specific piece of equipment.

Emphasize that once the derating of any conductor occurs, that Section 240.4 (B) does

not apply. The derated wire must not be attached to the next higher rated overcurrent

device, but must be set back to the next LOWER OCPD.

In general, conductors other than flexible cords and fixture wires, shall be protected against overcurrent in accordance with their ampacity as specified in Tables 310.16 through

310.19 and their notes.

Flexible cord shall be protected against overcurrent in accordance with their

ampacity listed in Table 400.5.

Fixture wire shall be protected against overcurrent in accordance with its

ampacity as shown in Table 402.5.

You should study and be familiar with the standard ampere ratings for fuses and

inverse time circuit breakers listed in Section 240.6.

Fuses or circuit breakers or combinations thereof shall not be connected in

parallel unless they are factory assembled and approved as a unit.

A thermal cutout, thermal relay, or other thermal device designed to protect motor

branch circuit conductors from overload and not designed to open short circuits shall not be

used to protect conductors against overcurrent due to short circuits or grounds.

Supplementary overcurrent protection shall not be used as a substitute for branch

circuit overcurrent devices. Supplementary overcurrent devices do not have to be readily

accessible.

Review the importance of electrical system coordination. (240.12)

In general, an overcurrent device shall be connected in series with each

ungrounded conductor. Circuit breakers shall open all ungrounded conductors of the circuit.

Listed devices providing equivalent protection in closed-loop power distribution

systems shall be permitted as a substitute for fuses or circuit breakers.

Read Section 240.21, in its entirety, to the class and discuss.


No overcurrent device shall be connected in series with any conductor that is

intentionally grounded (neutral) unless it is so designed so that no pole can operate

independently and it opens all conductors of the circuit. There is also an exception for motor

overload protection.

Where a change occurs in the size of the ungrounded conductor, a similar change shall

be permitted to be made in the size of the grounded conductor.

Overcurrent devices shall be readily accessible with the exception of busways,

supplemental overcurrent devices, service equipment as covered in Section 230.92 and

overcurrent devices located adjacent to the equipment they supply.

Except for multiple occupancy building and guest rooms in hotels and motels under

continuous management supervision, overcurrent devices shall be readily accessible to

the occupants.

Overcurrent devices shall be located where they will not be exposed to physical

damage or located in the vicinity of easily ignitable material such as in clothes closets. Branch

circuit, Service and Feeder overcurrent devices are not allowed in bathrooms located in

dwelling units or guest rooms of hotels and motels.

Unless part of an assembly that provides equivalent protection or mounted on open-

type switchboards, panelboards, or control boards, overcurrent devices shall be enclosed in

cabinets or cutout boxes.

If installed in damp or wet locations enclosures for overcurrent devices shall be

identified for use in such locations and shall be mounted at least 1/4 inch off its supporting

surface.

Enclosures for overcurrent devices shall be mounted in a vertical position unless it is

shown to be impracticable.

If accessible to other than qualified persons disconnecting means shall be provided on

the supply side of all fuses or thermal cutouts in circuits of over 150 volts to ground and

cartridge fuses in circuits of any voltage so that each individual circuit contains fuses or

thermal cutouts can be independently disconnected from the source of electric energy. Note

the two exceptions to this in Section 240.40.

Fuses and circuit breakers shall be so located or shielded that persons will not be

injured by their operation or movement of their handles or levers.

Plug fuses and fuseholders shall not be used in circuits exceeding 125 volts between

conductors except in circuits supplied by a system having a grounded neutral and having no

conductor at over 150 volts to ground.

Each fuse, fuseholder, and adapter shall be marked with its ampere rating.


When the fuse is installed there shall be no live parts exposed.

Plug fuses of 15 ampere and lower rating shall be identified by a hexagonal

window or cap.

The screw shell of a plug-type fuseholder shall be connected to the load side of the

circuit.

Edison-base plug fuses shall be classified at not over 125 volts and 30 amperes and

below. They shall be used only for replacements in existing installations where there is no

evidence of overfusing or tampering. Emphasize this concept!

Edison-base fuseholders shall be installed only where they are made to accept Type S

fuses by the use of adapters. (240.52)

Type S fuses shall be classified at not over 125 volts and 0 to 15 amperes, 16 to 20 amperes, and 21 to 30 amperes. They shall not be interchangeable with a lower ampere

classification and so designed that they can not be used in any fuse holder other than Type S

fuseholders or adapters. [240.53 (A) (B)]

Type S fuseholders and adapters shall be designed so that no fuse other than a Type S

fuse can be used in them. Type S adapters shall fit Edison-base fuse holders and shall be so

designed that once inserted in a fuseholder, they cannot be removed. Type S fuse, fuseholders,

and adapters shall be so designed that tampering or shunting (bridging) would be difficult.

They shall be standardized to permit interchangeability regardless of manufacturer. [240.54 (A-

E)]

Cartridge fuses and fuseholders of the 300 volt type shall not be used in circuits of over 300 volts between conductors except in circuits supplied by a system having a grounded

neutral and having no conductor at over 300 volts. [240.60(A)]

0 - 6000 ampere fuseholders shall be so designed that it will be difficult to put a fuse of any given class into a fuseholder that is designed for a current lower or voltage higher than

the class to which it belongs. Fuseholders for current limiting fuses shall not permit insertion

of fuses that are not current limiting. [240.60(B)]

Fuses shall be plainly marked showing the following:

1. ampere rating

2. voltage rating

3. interrupting rating where other than 10,000 amperes

4. "current limiting" where applicable

5. name or trademark of the manufacturer.

Cartridge fuses and fuseholders shall be classified according to voltage and amperage ranges, fuses rated 600 volts, nominal or less, shall be permitted to be used for voltages at

or below their ratings.


Circuit breakers shall be trip free and capable of being closed and opened by manual

operation. They can be operated by other means as electrical or pneumatic if manual

operation is also provided.

Circuit breakers shall clearly indicate whether they are open "off" or closed "on". If

operated vertically, the "up" position of the handle shall be the "on" position. Refer back to

Sections 240.33 and 240.81.

A circuit breaker shall be designed to require dismantling or breaking of a seal for any

alteration of its trip point or the time required for its operation for other than intended

adjustments.

Circuit breakers shall be marked with their ampere rating in a manner that will be

durable and visible after installation. If rated at 100 amperes or less and 600 volts or less they

shall be marked into their handle. When other than 5,000 amperes the interrupting rating shall

be shown on the circuit breaker.

When used as switches in l20-volt and 277-volt fluorescent lighting circuits, circuit breakers shall be marked "SWD" or HID. High-intensity discharge lighting circuits shall be

listed and shall be marked HID. [240.83(D)]

It should be noted that circuit breakers with a slash voltage rating (for example

120/240V) should not be applied in circuits where the voltage to ground exceeds the lower

of two voltage ratings.

Temperature ratings of circuit breakers should be discussed at some point while on the subject of circuit breakers.

APPLICATION:

If time allows, let the class answer the questions on the worksheet.




OVERCURRENT PROTECTION ARTICLE

240

LEVEL I

WORKSHEET

1. Which of the following is provided for conductors and equipment to open the circuit if the current reaches a value that will cause an excessive or dangerous temperature in

conductors or conductor insulation.

a. Thermal overload devices.

b. Thermistors in wiring devices.

c. Overcurrent protection devices.

d. Heat detectors in line fuses.

2. Plug fuses shall be marked with which of the following?

a. Heat value

b. Ampere rating c. Circular mils

d. Minimum circuit ampacity

3. When are fuses allowed to be connected in parallel.

a. When installed in the field.

b. When factory assembled

c. When required by the Electrical Inspector d. When required by the Electrical provider.

4. Which of the following are two types of fuses.

a. Plug and Cartridge

b. Load and Thermal

c. Screwshell and Keyless

d. GFCI and GFI

5. Plug fuses shall not be rated over which of the following volts?

a. 125 volts

b. 600 volts

c. 300 volts

d. 400 volts


6. Over current devices shall be readily accessible and shall be installed so that the center

of the grip of the operating handle of the switch or circuit breaker, when in its highest

position, is not more than which of the following above the floor or working platform

unless one of the following applies

a . 6’7”

b . 8’6” c . 6’

d . 7’6”

7. The screw shell of a plug-type fuseholder shall be connected to which side of the

circuit?

a. The line side.

b. The other side.

c. The load side

d. The high side

8. An overcurrent device shall be connected with each grounded conductor in which of the

following manners.

a. parallel

b. sequentially

c. thermally

d. series

9. In general, overcurrent devices shall be located in accordance with which of the following?

a. Where the conductors receive their supply.

b. Where the conductors are connected the appliance.

c. Where the service lateral originates.

d. Where the service lateral terminates.

10. A feeder consists of two 500 kcmil THW copper conductors connected in parallel. The

maximum rating of the overcurrent device protecting the feeder is:

a. 800 amperes

b. 600 amperes

c. 750 amperes d. 400 amperes


11. When overcurrent devices are installed, they shall be located in which of the

following type locations?

a. accessible

b. readily accessible

c. easily accessible

d. nearly accessible

12. When overcurrent devices are installed, they shall not be installed so as to be which of

the following?

a. Subject to physical damage.

b. Exposed to physical damage.

c. Exposed to sunlight.

d. Exposed to radiation.

13. Circuit breakers may be capable of being electrically opened if they are also

capable of being opened in which other manner?

a. Electronically

b. Normally

c. Separately

d. Manually

14. Which of the following four items of information are not required on each

cartridge fuse?

a. amperage rating

b. date of manufacture

c. voltage rating

d. interrupting rating

15. Which of the following is not a standard ampere rating for a circuit breaker?

a. 25 amperes

b. 110 amperes

c. 45 amperes

d. 55 amperes


16. The ampacity of a conductor, 21 feet in length, that is tapped to a feeder protected by a

400 ampere fuse shall not be less than which of the following ampere ratings?

a. 40 amperes

b. 100 amperes

c. 133 amperes

d.. 400 amperes

17. Which of the following is the maximum size type S fuse in amperes?

a. 20 amperes

b. 30 amperes

c. 50 amperes

d. 60 amperes

18. A 120 volt or 277 volt circuit breaker used to switch fluorescent lighting circuits shall be

marked as which of the following?

a. SWD

b. HID

c. CO/ALR d. Either a or b

19. Tap conductors permitted to be made without overcurrent protection that are

rated at 27 amperes would be provided with an OCPD at which of the following

ratings?

a. 30 amperes

b. 25 amperes

c. 20 amperes

d. 35 amperes

20. Flexible cord used in listed extension cord sets shall be considered to be

protected when?

a. the load is limited to the rating of the overcurrent device protecting the

branch circuit..

b. applied within the extension cord listing requirements.

c. GFCI devices are installed.

d. limited to use on lighting circuits and no greater than a 20 ampere overcurrent is installed.


OVERCURRENT PROTECTION ARTICLE 240

LEVEL I

ANSWER KEY

1. c, overcurrent protection 240.1(FPN)

2. b, ampere rating 240.50(B)

3. b, factory assembled 240.8

4. a, plug; cartridge 240.(V&VI)

5. a, 125 volts 240.50(A)

6. a, 6’7” 240.24(A)

7. c, load 240.50(E) 8. d, series 240.20(A)

9. a, point of supply 240.21

10. a, 800 amperes 240.4(B) 11. b, readily accessible 240.24

12. b, exposed 240.24(C)

13. d, manually 240.80 14. b, date of manufacture 240.60(C)

15. d, 55 amperes 240.6

16. c, 133 amperes 240.21(B)(2)(1)

17. b, 30 amperes 240.53(A)

18. d, "SWD" or HID 240.83(D)

19. b, 25 240.21(B) 20. b 240.5(B)(3)


GROUNDING ARTICLE 250

LEVEL I

OBJECTIVE:

Each student should know the importance of grounding and the general requirements for grounding and bonding electrical installations.

INTRODUCTION:

Using Soares book "Grounding Electrical Distribution System for Safety" go over the history of

grounding. Cover the reasons for grounding: (1) limit voltage due to lighting, line surges, or

unintentional contact with higher voltage line; (2) to stabilize the voltage to ground during normal

operations; and (3) to facilitate overcurrent device operations in case of ground faults.


Circuit and System Grounding Discuss Sections 250.4 and 250.20 thoroughly.

Location of System Grounding Connections

When grounding electrical systems care must be taken that methods are used to prevent objectionable flow of current over the grounding conductor. Temporary currents resulting from

accidental conditions such as ground-fault currents are not objectionable currents. This is the

purpose of grounding connections. 250.4 (A)

Once it has been determined that a premises system is required to be grounded there are several places the grounded electrode conductor (GEC) may be connected to the grounded

(neutral) conductor.

Note: Go over definitions of grounded electrode conductor, grounded conductor, and grounding

electrode.

The grounded electrical conductor shall be connected at any accessible point from the load end of

the service drop or lateral to and including the terminal or bus to which the grounded service

conductor in the service disconnection means is connected.

Note: Some power suppliers by their conditions of service, require the GEC to be

attached at the service head or may prohibit it from being connected in their metering

equipment.


A grounding connection shall not be made to any grounded circuit conductor on the load side

of the service disconnect mean except for the following conditions:

1. for separately derived systems (250.30)

2. at separate buildings (250.32) 3. for ranges etc. (250.140)

These conditions will be covered in detail later in the lesson.

Another condition that allows the grounded electrical conductor to be connected to

something other than the grounded conductor or bus bar is when the main bonding jumper*

is a wire or busbar. The grounded electrical conductor may be connected to the equipment

grounding terminal bar or bus to which the main bonding jumper is connected. * See

definition of main bonding jumper.

The grounding conductor must be brought to the service equipment when an AC system operates at less than 1000 volts and is grounded. The minimum size is based on Table 250.66

but is not required to be larger than the largest ungrounded conductor.

Note: Required to provide an effective path for ground fault currents to facilitate overcurrent devices. [250.4(A)(5)]

Where one building or structure is fed from another building and there are no metallic paths

between them the second building shall have the AC system grounded circuit conductor and

the metal enclosure of the building disconnection means connected to a required grounding

electrode. Where there is only one branch circuit and there is nothing in the building that

requires grounding the grounding electrode is not required.

When an equipment grounding conductor (EGC) is run with the circuit conductors feeding

into the second building the grounded circuit conductor (neutral) need not be connected to a

grounding electrode at the second building where the equipment grounding conductor (EGC)

is brought to the second building it is used to ground any noncurrent-carrying equipment,

interior metal piping systems or structural frames and bonded to the building disconnecting

means. The equipment grounding conductor must be connected to any existing grounding

electrode and if none exist then one must be provided if there is more than one branch

circuit at the second building.

Note: 250.32(D) requires alternations if the disconnecting means is not located in the second

building.

If livestock is housed, that portion of the equipment grounding conductor run underground shall be insulated in covered copper.


Abbreviations:

UCC — ungrounded circuit conductors GCC — grounded circuit conductor EGC — equipment grounding conductor GEC — grounding electrical conductor BJ — bonding jumper

Discuss the different AC systems. The conductor that is required to be grounded is

specified as follows: (250-26)

1. Single-phase, 2-wire, one conductor. 2. Single-phase, 3-wire, the neutral conductor.

3. Multiphase system having one wire common to all phases, the common

conductor.

4. Multiphase systems where one phase is grounded – one phase conductor

5. Multiphase system in which one phase is used as in (2) above the neutral

conductor.

A separately derived AC system that is required to be grounded shall be grounded as

follows: (250.30)

1. Main Bonding Jumper — A bonding jumper shall be used to connect the grounding

conductors to the grounded conductor. This shall be done at any point from the

source to the first disconnection means. The bonding jumper is sized based on the

derived phase conductor in accordance with 250.28.

2. Grounding Electrode Conductor — The GEC is used to connect the conductor required

to be grounded to the grounding electrode. This connection is to be made at any point

from the source to the first disconnection means. The GEC is sized based on the derived

phase conduction in accordance with Section 250.66.

3. Grounding Electrode — The GEC shall be the nearest available effectively grounded

structural metal member; or the nearest available effectively grounded metal water

pipe; or other electrode if the first two are not available. (250.50)

Enclosure Grounding

Metal enclosures are required to be bonded and grounded and continuity of metal

raceways assured. This is required to provide an effective path for ground fault current.

Short section of metal enclosures for support or protection of cable assemblies are not

required to be grounded. Example- short section of EMT run exposed down a wall to

protect a NM cable.


Equipment Grounding

Exposed noncurrent carrying metal parts of fixed equipment likely to become

energized shall be grounded as follows: (See also Section 250.110)

1. Where within 8 feet vertically or 5 feet horizontally of ground or grounded metal

objects and subject to contact by persons.

2. In wet or damp locations not isolated.

3. In electrical contact with metal

4. In hazardous locations

5. Where supplied by wiring methods which provides an equipment ground.

6. Where equipment operates at over 150 volts to ground.

Note: There are circumstances because of insulation or double insulation where

grounding is not required.

Methods of Grounding

Equipment grounding conductor connections — EGC at service equipment shall be

connected to the grounded services conductor and GEC. When replacing a nongrounding

type receptacle with grounding-type receptacle in existing installations the grounding conductor of a grounding-type receptacle shall be permitted to be grounded to water

pipe where bonded according to Section 250.104(A). Note: GFCI type of receptacle also

permitted. (250.130; see also Section 250, Part VII) The grounding path shall be: (1) be

permanent and continuous; (2) have capacity to conduct safely the fault current; and (3)

have sufficiently low impedance to limit voltage to ground and to facilitate the operation

of overcurrent devices. Note that the earth is not to be relied upon as the sole equipment

grounding conductor.

(250.4(A)(5)

Example: Pole lighting circuits must contain an EGC to ground the noncurrent carrying

metal as the pole light a driven ground rod at the pole does not meet the requirement

of this Section, but can be installed as supplemental grounding.

The grounding electrode used to ground an AC system of a building shall be the same

electrode used to ground raceway and equipment in buildings as well as other services

in the building. Multiple electrodes effectively bonded together shall be considered as

one. (250.58)

Equipment requiring grounding shall be grounded by an equipment grounding conductor

run with the circuit conductors. This conductor may be bare, covered, or insulated. If

covered or insulated it shall be green or green with yellow stripes. Insulated or covered

conductor larger than No. 6 may be permanently identified by other means such as

striping, coloring, or marking type. (250.119)


A grounded circuit conductor (neutral) may be used to ground noncurrent- carrying metal

parts of service equipment but may not be used to ground equipment on the load side of

service equipment, except as previously covered in Sections 250.32 and 250.60.

Bonding

Bonding is provided to assure electrical continuity and to conduct safely any fault

current.

Service raceways, service equipment enclosures, and raceway enclosing the GEC all

must be bonded together. An intersystem bonding termination for connecting

intersystem bonding and grounding conductors required for other systems shall be

provided external to enclosures at the service equipment and at the disconnecting

means for any additional buildings or structures. In existing buildings or structures, an

accessible means external to enclosures for connecting intersystem bonding and

grounding electrode conductors shall be permitted at the service equipment and at

the disconnecting means for any additional buildings or structures by at least one of

the following means: (250.94)

1. Exposed metallic service raceways.

2. Exposed grounded electrical conductor.

3. Approved means for external connection: a 6 inch free end of a #6 copper conductor connected to the service raceway of equipment is one example

Of an approved means. (250.94 FNP No.1)

Bonding of service equipment may be assured by one of the following methods:

[250.92(A)(B)]

1. Grounded service conductor.

2. Threaded couplings and threaded hubs.

3. Threadless coupling and connectors, regular locknuts or bushings do not meet the

requirement of bonding for services.

4. Bonding Jumpers.

5. Other approved devices.

The grounding terminal of a grounding-type receptacle must be grounded to the box

by an equipment bonding jumper. The exceptions covering direct metal-tometal

contact, cover-mounted receptacles, device listed for the purpose and special

receptacles used for reduction of electrical noise should be covered. (250.146)

Bonding of metal raceways containing circuits of over 250 volts to ground other than

service conductor shall be bonded the same as service raceways. When punched

knockouts (not oversized, concentric, or eccentric) the following shall be permitted:

1. Threadless coupling and connectors for cables with metal sheaths.

2. Two locknuts - one inside , one outside on rigid or IMC.


3. Fitting with shoulders such as EMT connector. (250.97)

A main bonding jumper shall be a wire, bus, screw, or similar suitable conductor.

[250.28(A)]

The main bonding jumper is sized to be not smaller than the sizes given in Table 250.66

based on the size of the installed service conductors.

Example: A 200-amp service is installed with 4/0 THW Aluminum service

conductor. What size main bonding jumper is required?

Solution: Table 250-66. Use column for Aluminum conductor, find 4/0 size

conductor and read across to #4 copper on #2 aluminum conductor.

The equipment bonding jumper on the load side of service equipment is sized using

Table 250.122 based on the overcurrent device supplying circuit therein.

Example: A 200 amperes feeder supplies a panelboard. The metal conduit must

be bonded in the service equipment. What size equipment bonding jumper is

required to bond this conduit?

Solution: Using Table 250.122 go to column for overcurrent sizes- read down to 200

amp- go over to #6 copper or #4 aluminum.

The interior metal water piping system (this water piping system may not meet

requirements to be considered a grounding electrode) shall be bonded to the (1)

service equipment enclosure (2) grounded conducted at the service, or (3) the

grounding electrodes. The bonding jumper is sized using Table 250.66. The point of

attachment shall be accessible. (250.104)

In multiple occupancy building where the interior metal water piping system is "high and

dry" and isolated from other occupancies by use of nonmetallic water piping, the

interior metal water piping for each occupancy may be bonded to the subpanel with a

bonding jumper sized according to Table 250.122. (Use size of overcurrent feeding

subpanel) The equipment grounding conductor for the circuit servicing equipment that

may energize other metal piping shall be permitted to bond said piping.

Grounding Electrode System

A metal underground water pipe (in direct contact with earth for 10 feet or more) and the effectively grounded metal frame of the building shall be bonded together

to form a grounding electrode system. The bonding conductor is sized based on 250.66.

All electrodes present must be used. (250.50)


North Carolina Amendment 250.50

Delete NEC 250.50 and replace with:

250.50 Grounding Electrode System. If available on premises at each building or structure

served, each item in 250.52(A) (1) through (A)(6) shall be bonded together to form the

grounding electrode system. Where none of these electrodes are available, one or more

of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

A rod, pipe, or plate electrode must have a resistance to ground of 25 ohms or less or be

augmented by one additional electrode. Multiple rods, pipes, or plates must be at least 6

feet apart. (250.56)

Grounding Conductor

The electrical grounding conductor (EGC) shall be in one continuous length; solid or

stranded, insulated, covered or bare and of copper, aluminum, or copper-clad aluminum.

Equipment grounding conductors shall be as in 250.118:

1. A copper or other corrosive- resistance conductor in the form of a wire or

busbar.

2. Rigid metal conduit.

3. IMC

4 . E M T

5. Flexible metal conduit when listed for grounding.

6. Armor of Type AC cable.

7. Sheath of MI cable.

8. Metallic sheath or the combined metallic sheath and grounding conductors

of Type MC cable.

9. Cable trays.

10. Other metal raceway listed for grounding.

Flexible metal conduit and Liquidtight flexible metal conduit may be used for grounding

when they meet requirements listed in Sections 250.118, 349 and 350.

The GEC or its enclosure shall be securely fastened to the surface on which it is carried. A

#6 or larger GEC, when free from physical damage may be installed without protection

when securely fastened. GEC smaller than #6 shall be


installed in rigid metal conduit, IMC, EMT, rigid nonmetallic conduit, or cable

armor. (250.62)

Metal enclosure for GEC shall be electrically continuous from the cabinet or

equipment to the grounding electrode. If not they shall be made electrically

continuous by bonding each end to the GEC. [250.62(E)]

GEC's are sized as per Table 250.66 unless it is the sole connection to such made

electrode as discussed in 250.66 (A). Where the grounding electrode conductor is

connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5) or (A)(6),

that portion of the conductor that is the sole connection to the grounding

electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG

aluminum wire.

The EGC is sized based on Table 250.122. Show these tables and explain.

Grounding Conductor Connections

The connection of the GEC to the grounding electrode shall be accessible. The

connection shall be by one of the following methods: (250.70)

1. Exothermic welding

2. Listed lugs

3. Listed pressure connectors

4. Listed clamps

5. Other listed means

EGC shall be spliced or joined in accordance with Section 110-14(B) except for

insulation, when more than one EGC enter a box. The removal of a receptacle,

fixture or other device shall not interrupt the grounding continuity.

APPLICATION:

If time allows, let the class answer the questions on the

worksheet. CHECKING AND FOLLOW UP :

If time allows, correct worksheets and discuss the results.

GROUNDIN


G ARTICLE 250 LEVEL I

WORKSHEET

1. A “system bonding jumper” is which of the following?

a. the connection between the grounded circuit conductor and the equipment grounding conductor at a separately derived system

b. the connection between the grounded circuit conductor and the equipment

grounding conductor at the service. c. the connection between two or more portions of the equipment


d. the permanent joining of metallic parts to form an electrically conductive

path that ensures electrical continuity and the capacity to conduct safely any

current likely to be imposed.

2. Which of the following statements is/are true?

I. A bare aluminum grounding electrode conductor that is physically

protected can be connected to an outside buried ground rod.

II. An insulated aluminum grounding electrode conductor can be connected

to an outside buried ground rod if physically protected.

a. I only

b. II only

c. both I and II

d. neither I nor II

3. A main disconnect circuit breaker is installed outside in a weatherproof

enclosure below the meter feeding a distribution panel in the basement of a

residence. Which of the following statements conforms to NEC requirement?

I. Service grounding must be done at the service disconnecting means.

II. The distribution panel neutral bar must be bonded to the cabinet.

a. I only

b. II only c. both I and II

d. neither I nor II


4. It is permissible to connect the grounding electrode conductor:

I. at the service disconnect means

II. on the load side of the service disconnect

a. I only

b. II only

c. both I and II

d. neither I nor

5. The maximum required size copper grounding electrode conductor to a ground rod with paralleled 4/0 TW service conductors is:

I. 1/0 copper II. 6 copper

a. I only

b. II only

c. both I and II

d. neither I nor II

6. The minimum size copper equipment grounding conductor required for

equipment connected to a 40 ampere circuit is:

a. #12

b. #14

c. #10

d. #8

7. A main bonding jumper is which of the following?

a. the connection from the equipment ground to all non current carrying

metal parts.

b. the grounding conductor on the load side of the service disconnecting

means.

c. the connection between the grounded circuit conductor and the equipment

grounding conductor at the service.

d. the conductor from the grounded conductor to the grounding electrode.


8. If separate grounding electrodes are used on the CATV, telephone and electrical service;

what is the minimum size conductor required to bond these systems together?

a. #6

b. #8

c. #10

d. #14

9. Which of the following shall not be used to connect grounding conductors or connection

devices to enclosures?

a. Pressure connectors

b. Sheet metal screws

c. Exothermic welding

d. Listed clamps

10. Electrical continuity for bonding service equipment shall be assured by the following

method(s):

a. grounded service conductor

b. threaded couplings

c. bonding jumpers

d. approved bonding devices

e. all of the above

11. Connecting the receptacle grounding terminal to a metal box may be accomplished by the use of:

I. Bonding jumper II. Neutral conductor

(a) I only (c) both I and II (b) II only (d) neither I nor II

12. The following may be included in the grounding electrode system:

I. metal underground water pipe


II. metal frame of building

a. I only

b. II only

c. both I and II

d. neither I nor II

13. Air Terminals conductors, driven rods, pipes or plate electrodes used for grounding air

terminals shall not be used in lieu of which of the following?

a. A grounding electrode system.

b. A single grounded electrode system. c. An exothermic welded system.

d. A building bonding system.

14. Which of the following grounding electrodes as described in 250.52(A)(1)

through (A)(6) shall be bonded together to form the grounding electrode

system.

a. That is specified by the AHJ.

b. That is available at each building. c. That is specified by the Electrical Engineer.

d. That is present at each building.

15. The equipment bonding jumper on the load side of the service overcurrent devices

shall be sized, as a minimum, in accordance with the sizes listed in Table 250.122,

but shall not be required to be larger than the largest ungrounded circuit conductors

supplying the equipment and shall not be smaller than which AWG?

a. 14 b. 12

c. 10

d. none of the above

16. Which of the following shall not be permitted to be used as an effective fault- current path.

a. The plate electrode. b. The grounded conductor.

c. The grounding conductor.

d. The earth.


17. What size copper conductor is required for the grounding electrode conductor on a

service with 2/0 copper conductors:

a. # 8

b. # 6

c. # 4

d. # 2

18. All metal enclosures for service conductors and equipment must be properly?

a. painted

b. bonded

c. sealed

d. grounded

19. A means must be provided for disconnection of the grounded conductor of a

service from the premises wiring. This may be which of the following?

a. A terminal or bus with pressure connectors.

b. A wire binding screw and a pressure connector.

c. A wire nut connector.

d. None of the above

20. A grounded circuit conductor may be used to ground the frame of a range under

which of the following conditions?

a. In new installations.

b. In existing installations.

c. In new multi-family dwellings.

d. In new apartments and townhouses.

21. A metal underground water pipe may serve as a grounding electrode under which of

the following conditions.

a. If it is in direct contact with the earth and 10 feet in length.

b. If it is electrically continuous.

c. If it has no insulated joints.

d. All of the above

22. The grounded conductor for a service shall not be smaller than the size of the:

a. grounding electrode conductor b. equipment grounding conductor

c. ungrounded service conductor

d. any of the above


23. The main bonding jumper must not be smaller than the size of:

a. The grounding electrode conductor. b. The equipment grounding conductor.

c. The equipment bonding jumper.

d. None of the above.

24. Rod and pipe electrodes must not be less than how many feet in length?

a. 4

b. 6

c. 8 d. 10

25. For a grounded system, a main bonding jumper is required to connect which of the following?

a. equipment grounding conductors

b. service equipment enclosure

c. grounded service conductor

d. all of the above

26. Which of the following may not be used for attaching grounding conductors to

circuits or equipment?

a. Exothermic welded connections.

b. Listed pressure connectors.

c. Soldered lugs.

d. Other listed means.

27. Which of the following may be used as a grounding conductor?

a. copper conductor b. aluminum conductor

c. copper-clad aluminum

d. all of the above

28. In an existing branch circuit installation where a grounding conductor is not present in

the junction box, it is permissible to utilize a neutral conductor as an equipment

grounding conductor. The minimum size is not to be less than?

a. # 10 copper or # 8 aluminum

b.# 8 copper or # 10 aluminum c.#

6 copper or # 4 aluminum d.This is

not allowed.


29. Electrical systems that are grounded shall be connected to earth in manner that will

limit the voltage imposed by which of the following except for?

a. Lightning

b. Line surges

c. Unintentional contact with higher voltages

d. Ungrounded circuits

30. System grounding electrode conductors of the following size(s) are required to be installed in a metallic raceway for mechanical protection.

a. 4

b. 6

c. 8

d. all of the above

31. Bonding jumper(s) from grounding electrode(s) and grounding electrode

conductor(s) shall be installed in one continuous length without splice or joint

and shall be permitted to be connected to an aluminum or copper busbar not

less than which of the following in size?

a . 1/2 x 1

b . 1/2 x 2

c . 1/4 x 2

d . 1/4 x 3


GROUNDING

ARTICLE 250

LEVEL I

ANSWER KEY

1. a

2. d, neither I nor II

3. a, I only

4. a, I only

Article 250.2, Definitions 250.64(A)

250.142

250.24, 250.142

5. b, II only 250.66(A) 6. c, #10 250.122

7. c Article 100, Definitions

8. a, #6 250.94, 820-100(D)

9. b 250.8

10. e, all of the above 250.94 11. a, I only 250.146

12. c, both I and II 250.50

13. a 250.60

14. d 250.50

15. a, #14 250.102(D) 16. d, the earth 250.2, 250.54 17. c, # 4 250.66

18. d. 250.80

19. a. 230.75

20. b. 250.142

21. d. 250.52(A)(1)

22. a, grounding electrode conductor 250.24(C)(1) 23. a, grounding electrode conductor 250.28(D) 24. c, 8 250.52 25. d, all of the above 250.28 26. c. 250.8

27. d. 250.118

28. a. 250.140 exception 2

29. d. 250.2(A)

30. c, 8 250.64(B) 31. c 250.64(D)(1)(3)

D)(3)


SURGE ARRESTOR ARTICLE 280

LEVEL I

OBJECTIVE:

Each student should become familiarized with the general installation requirements of surge arrestors on premises wiring systems.

INTRODUCTION:

Explain to the class that you will cover Article 280 parts I, II, and III. Types and sizes of

conductors utilized depend on KV of Circuit.


Cover Article 280 in NEC, where arrestors are to be connected, one to each ungrounded

conductor, to the grounded service conductor, or grounding electrode conductor. Conductor size

will differ in circuits of 1 KV and over. Arrestors may be located inside or outside. The selection of

surge arrestors depends on voltage.


CHECKING AND FOLLOW-UP: If time allows, correct the worksheets and discuss the results. Insure students understand

Article 280.


SURGE ARRESTOR

ARTICLE 280 LEVEL I

WORKSHEET

1. Which of the following is/are correct concerning the installation of surge

arrestors?

I. In general, surge arrestors shall be made inaccessible to unqualified persons.

II. Surge arrestors shall be installed outdoors only.

a. I only b. II only

c. Both I and II

d. Neither I nor II

2. For circuits of 1 KV and over, The conductor between the surge arrestor and the line and

surge arrestor and the grounding connection shall not be smaller than:

(a)#8 Copper

(b) #6 Copper

(c) #4 Copper

(d) #3 Copper

3. Surge arresters shall comply with all the following with the exception of

a. The rating of the surge arrester shall be equal to or greater than the maximum

continuous operating voltage available at the point of application

b. The maximum continuous pertaining voltage shall be the phase-to-ground

voltage of the system

c. The maximum continuous operating voltage shall be the phase-to-phase voltage of

the system.

d. Surge arresters shall be permitted to be installed on ungrounded systems only.


91

SURGE ARRESTOR

ARTICLE 280 LEVEL I

ANSWER KEY

1. a, 280.11

2. b, 280.23

3. d 280.4(A)


WIRING METHODS

ARTICLE 300

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with various wiring

methods for all types of wiring installations.

INTRODUCTION:

In the USA, cable wiring is probably the most recognized wiring method, especially for

residential-type construction. The general requirements for wiring methods are listed

in the National Electrical Code, Article 300.

This assignment contains information about overcurrent protective devices and fuses,

sizes of conductors, types of conduit, installing boxes, grounding conductors, and

various raceways. This information will be very useful to the students in their daily

work on the job.

The students may not realize the fact, but it requires a skilled craftsman to make a

concealed electrical installation in an old building. It is essential that they leave the

building in good repair when they are finished.


The instructor should lead a class discussion of the material found in the assignment.

The students should have read the assignment and have questions for discussion ready

to present.

300.1 & 2 Scope and Limitations

Note that this Article covers all wiring installations unless modified by other Articles.

This Article does not pertain to conductors which are an integral part of equipment such

as motors and controllers Also, note voltage and temperature limitations in this Article.

300.3 Conductors

Various single conductors must comply with wiring methods in Chapter 3 of the Code. Discuss the housing or enclosure requirements of conductors of the same and different circuits.

300.4 Protection Against Physical Damage

Pay close attention to specifications for placing cables and raceways through wood

members, metal framing members and behind access panels. Review Section 300.4(E)

regarding cable- or raceway-type wiring method, installed in exposed or concealed


locations under metal-corrugated sheet roof decking and Section G that requires

protection of conductors 4 AWG or larger in raceways where entering an enclosure,

cabinet, box or raceway.

300.5 Underground Installations.

Cable, conduit, and raceways when buried underground have minimum cover

requirements detailed in Table 300.5. Review Section 300.5 (B) regarding the interior of

enclosures or raceways, splices and connections installed underground shall be

considered to be a wet location and shall comply with Section 310.10(C).

Show transparency of Table 300.5 and discuss.

Underground installations shall be grounded and bonded in accordance with Article

250. Also, note specifications for cables under buildings and the burying of cables.

300.6 Protection Against Corrosion

Guidelines for protection against corrosion of cable enclosures are explained in terms

of concrete, direct contact with earth, and wet indoor locations. Note 300.6 (B)

regarding Aluminum Metal Equipment.

300.7, 8 Raceways

Raceways should not be exposed to a wide range of different temperatures, particularly

the circulation of warmer air to a colder area through the raceway. This could cause

condensation and create damp conditions in the raceway. In addition, raceways should

allow for thermal contraction and expansion by having adequate expansion joints. No

electrical conductor shall be installed in a raceway with other service pipes or tubes

other than electrical.

300.9 Raceways in Wet Locations Above Grade.

Where raceways are installed in wet locations above grade, the interior of these

raceways shall be considered to be a wet location. Insulated conductors and cables

installed in raceways in wet locations above grade shall comply with 310.10(C).

300.11 Securing and Supporting

Enclosures and raceways for electrical conductors shall be securely supported with

rigid supports and may not be used as supports for other raceways or other non-

electrical equipment unless otherwise stated in exceptions. [See section 300.11 (B)]

Discuss the supporting of wiring above fire-rated and non-fire-rated floor/ceiling or

roof/ceiling assemblies and attachment thereto.

300.12, 13 Mechanical and Electrical Continuity


Raceways and cables shall be continuous and electrical conductors within them shall

not be spliced or tapped unless otherwise noted in exceptions of the Code.

300.14 Length of Free Conductors Discuss the length of free conductors at outlets, junctions, and switch points.

300.15 Boxes; Where Required Discuss where boxes are required for electrical conductors.

300.16 Raceway or Cable to Open or Concealed Wirings

Explain requirements for raceway or cable to open or concealed wirings.

300.17 Number and Size of Conductors in Raceway The number and size of conductors in a raceway shall not be more than will permit

dissipation of heat and ready installation or withdrawal of the conductors without

damage to the conductors or to their insulation. For more information see Section

300.17 of the Code.

300.18 Raceway Installations

Installation of raceways, other than busways or exposed raceways having hinged or

removable covers are to be complete from outlet, junction, or splicing points prior to

the installation of conductors. Metal raceways are not to be supported, terminated, or

connected by welding unless designed to be or otherwise specifically permitted in the

code.

300.19 Supporting Conductors in Vertical Raceways

Supporting conductors in vertical raceways is covered in terms of maximum spacing

intervals and support methods in Section 300.19 accompanied by a Table for spacing

requirements. Review Section 300.19 (B) support methods and spacing intervals for fire-

rated cables and conductors.

Show transparency of Table 300.19(A) and discuss.

300.20 Induced Currents in Ferrous Metal Enclosures and Ferrous Metal Raceways. Explain methods of controlling induced currents in metal enclosures with individual

conductors and grouped conductors.

300.22 Ducts, Plenums, and Other Air-Handling Spaces Discuss the rules of wiring in ducts, plenums and other air handling spaces.


CHECKING AND FOLLOW-UP: If time allows, correct the worksheet and discuss the results.


WIRING METHODS

ARTICLE 300

LEVEL I

WORKSHEET

1. The provisions of this Article are not intended to apply to which of the following?

a. the conductors which form an integral part of equipment.

b. The conductors for motors and motor control centers.

c. The conductors for motor controllers.

d. All of the above.

2. All conductors of the same circuit and where used, the grounded conductor and which of the

following shall be contained in the same raceway, cable tray, trench, cable or cord.

a. equipment grounding conductors, bonding conductors

b. bonding jumpers, grounded circuits c. grounding electrodes, electrode conductors

d. ground rings, grounding clamps

3. Cables and insulated conductors installed in enclosures or raceways in

underground installations shall considered to be what type of location?

a. damp

b. dry

c. wet

d. hazardous

4. Where cables or wires are installed through bored holes in wood members, the holes shall be bored so that the edge of the hole is not less than how many inches from the nearest edge

of the wood member.


c. 1 5/8 inches

d. 1 1/4 inches

5. The minimum cover requirement for direct buried cable of 1000 volts or less not

protected by concrete is:

a. 18 inches

b. 16 inches c. 24 inches



6. A residential branch circuit rated 120 volts or less and provided with GFCI protection

and maximum overcurrent protection of not more than 20 amperes will be directly

buried in soil. Minimum cover requirement shall be not less than which of the

following?


c. 6 inches

d. 18 inches

7. Where raceways containing ungrounded conductors are entering a box or

enclosure, a substantial fitting providing a smoothly rounded insulating surface

should be used when the conductors are of which of the following sizes?

a. 3 AWG or larger

b. 2 AWG or larger

c. 1 AWG or smaller

d. 4 AWG or larger

8. Where an enclosure or raceway is subject to physical damage and conductors

are installed in a non-metallic raceway, the raceway shall be which of the

following?

a. Schedule 40 rigid

b. Schedule 80 rigid

c. Schedule 120 rigid

d. Schedule 60 rigid

9. Conduits or raceways that contain live parts shall be sealed or plugged at

either or both ends if they may contact which of the following?

a. moisture

b. hazardous gases

c. hazardous vapors

d. all of the above


10. Where portions of a cable raceway or sleeve is subjected to different

temperatures, to prevent the circulation of warm air to a colder section of

the raceway or sleeve, which of the following shall be provided?

a. an insulated bushing

b. approved fill material

c. a non-explosionproof seal

d. an explosionproof seal

11. Raceways or cable trays containing electrical conductors shall not contain other

services such as the following?

a. Water lines b. Air lines

c. Gas pipes

d. all of the above

12. Conductors shall be continuous between outlets, devices, etc., and there shall be no

splice or tap within a raceway itself, unless permitted by which of the following?

a. 300.15 (A)

b. 368.56(A)

c. 376.56

d. All of the above

13. A box or conduit body shall not be required for each splice, junction, switch, pull, termination, or outlet points in wiring methods, such as wireways, multioutlet

assemblies, auxiliary gutters, and surface raceways if they are equipped with

which of the following?

a. a cover

b. an accessible removable cover

c. a readily accessible removable cover

d. an accessible cover

14. Regulating the number and size of conductors in any raceway is important to allow for


a. Permit dissipation of heat.

b. Allow for ready installation or withdrawal.

c. Removal of wiring without damage to the insulation.

d. All of the above


15. Conductors in vertical raceways shall be supported. In accordance with which of the

following?

a. Table 300.5 b. Table 300.19(A)

c. Table 310.16

d. Table C.11

16. Phase conductors carrying alternating current that are installed in metal raceways shall be

arranged to avoid heating the surrounding metal by which of the following?

a. induction b. convection

c. radiation

d. thermal expansion

17. Openings around electrical penetrations through fire-resistance rated walls,

partitions, floors or ceilings shall be fire-stopped using approved methods to

maintain which of the following?

a. the fire-resistance rating

b. the proper clearance

c. the thermal resistance

d. the reduction of harmonics

18. Which of the following wiring systems may be installed in ducts used for

environmental air?

a. MI Cable

b. MC Cable

c. EMT

d. All of the above

19. Where nonmetallic-sheathed cables pass through either factory or field punched,

cut, or drilled slots or holes in metal members, the cable shall be protected by which of the following?

a. listed bushings b. listed grommets

c. Either A or B d. Neither A nor B


20. In both exposed and concealed locations, where a cable or raceway-type wiring method is installed parallel to framing members, such as joists, rafters, or studs, or is installed parallel to furring strips, the cable or raceway shall be installed and supported so that the nearest outside surface of the cable or raceway is not less than which of the following from the nearest edge of the framing member or furring strips where nails or screws are likely to penetrate.

a. 1 1/4 inches

b. 1 inch

c. 3/4 inch

d. 1 3/4 inch

21. A cable- or raceway-type wiring method, installed in exposed or concealed

locations under metal-corrugated sheet roof decking, shall be installed and supported

so the nearest outside surface of the cable or raceway is not less than which of the

following distances from the nearest surface of the raceway?

a. 5/8 inch

b. 1 1/2 inches

c. 2 inches

d. 3/4 inch


WIRING METHODS

ARTICLE 300 LEVEL I

ANSWER KEY

1. d, all of the above 300.1(B)

2. a, equipment grounding conductors, bonding conductors 300.3(B) 3. c. 300.5(B)

4. d, 1 1/4 inches 300.4(A)(1)

5. c, 24 inches Table 300.5

6. b, 12 inches Table 300.5

7. d. 300.4(G) 8. b. 300.5(D)(4)

9. d. 300.5(G) & note

10. b. 300.7(A) 11. d. 300.8

12. d. 300.13(A)

13. d. 300.15(A)

14. d. 300.17

15. b. Table 300.19(A)

16. a. 300.20

17. a. 300.21

18. d. all of the above 300.22(B)

19. c. 300.4(B)(1) 20. a 300.4(D)

21. b 1 1/2 inches 300.4(e);


CONDUCTORS FOR GENERAL WIRING

ARTICLE 310

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the

requirements for conductors for general wiring.

INTRODUCTION:

Conductors for general wiring come in different sizes as well as having different insulation on

the conductor. It can come in single conductors or in a cable assembly. The conductors can be

solid or stranded also copper, aluminum, or copper clad aluminum. As voltages change, so can

the requirements for conductors. In this lesson we will take a look at these different

requirements.

MATERIALS NEEDED :

Samples of different kinds of conductors (i.e. single conductor, cables, conductors with

different types of insulation.


Conductors and cables used in wet locations must be (1) moisture impervious metal

sheathed, (2) type MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW,

XHHW-2, ZW or (3) listed for wet locations. (310.10[C])

Conductors used for direct burial shall be of a type identified for such use. (310.10[F])

Conductors exposed to direct sunlight must be listed as sunlight resistant or covered with a

material listed and marked as sunlight resistant. (310.10[D])

Conductors used in corrosive conditions must be of a suitable type. (310.10[G])

Read carefully about conductors installed in parallel in section 310.10 (H), paying close

attention to the exceptions and Conductor and Installation characteristics.

Conductor must not exceed the temperature for which it is rated. ( 310.15 [A] 3)

Review ampacities for general conductors and Tables 310.15. Show the students how to interpret

the Tables. Note changes to numbering (e.g. 310.16 is now 310.15[B] 16)


Note that each Table is based on a certain ambient air temperature. If the conductor

installation exceeds this ambient, then the ampacity in the Table must be multiplied by the

correction factor based on the temperature the conductor is to encounter. (see table

310.15 [B] 2.a or b.)

There is also a temperature adder for conductors exposed to sunlight on rooftops. (310.15

[B] 3.c, see exception for XHHW-2)

Note that 310.15(B)(3)(a) has further reductions for more than 3 current-carrying

conductors in a raceway or cable or where spacing is not maintained. The neutral shall not

be counted when making these demand calculations except per 310 15 (B) 5.

Note 310.15 (B) 7 which deletes the table and replaces it with a reduction to 83% of required

ampacity. (see example D-7 in Annex D)

The minimum size of conductors for various voltages are found in Table 310. 106(A).

Conductors in this article shall be of aluminum, copper-clad aluminum, or copper unless otherwise

specified. (310.106[B])

When installed in raceways, conductors #8 and larger shall be stranded unless specifically permitted

or required elsewhere in this code. (310.106[C])

Conductors shall be insulated unless specifically permitted elsewhere in the code. (310.106[D])

Ungrounded conductors shall be distinguishable from grounded and grounding conductors.

(310.110[C])

Conductors must be marked with maximum voltage, conductor or cable type, manufacturer's name or

trademark, and wire size at intervals not to exceed 24” or 40”. (310.120[A&B])

Metal-covered multi-conductor cable shall have a marker tape within the cable along its entire length.

Exceptions would be MI cable, AC cable, MC, ITC or PLTC cable.(310.120 [B]2)

APPLICATION: If time allows, let the class answer questions on the worksheet.

CHECKING AND FOLLOW UP : If time allows, correct the worksheets and discuss the results.



ARTICLE 310

LEVEL I

WORKSHEET

1. The largest solid conductor that can be pulled in a raceway unless specifically permitted or required elsewhere in the code:

a. #14

b. #12

c. #10

d. #8

2. in general, conductors must be at least what size and larger to be paralleled?

a. 1/0

b. 2/0

c. 3/0

d. 4/0

3. Cables and conductors marked THW with maximum voltage of 600 volts

manufacture southwire must have this marking not exceeding

a. 40 inches

b. 36 inches

c. 30 inches

d. 24 inches

4. The minimum size copper conductor for 0 to 2000 volts is:

a. 16

b. 14

c. 12 d. 10

5. The ampacity of a #4 copper THW conductor run in ambient temperature of 40 degrees Celsius in a conduit with 3 current carrying conductors are:

a. 75

b. 74.8

c. 85

d. 65


6. The minimum size of the service conductors to a single family dwelling with a 125 amperes service using THW aluminum is:

a. #4

b. #2

c. #1/0 d. #2/0

7. Six 1/0 THW copper conductors are run in parallel, in the same raceway, two conductors

per phase, on a three phase system. The conductors must be derated to what percent

of their normal ampacity.

a. 20 percent

b. 30 percent

c. 60 percent

d. 80 percent

8. Insulated conductors or cables used where exposed to direct rays of

the sun shall comply with all of the following with the exception of?

a. Cables must be listed, or listed and marked, as being sunlight resistant b. Conductors must be listed, or listed and marked, as being sunlight resistant.

c. Covered with insulating material, such as tape or sleeving, that is listed, or listed

and marked, as being sunlight resistant

d. Conductors exposed to direct sunlight must be terminated to an over current

device rated at no more than 60 amperes.



ARTICLE 310

LEVEL I

ANSWER KEY

1. c, #10 310.106 (C)

2. a, 1/0 310.15 (H) 1

3. a, 40 inches 310.120(B)(1)

4. b Table 310.106 (A)

5. b, 74.8 310.15(B)16, 310.15(B)(2)(a)

6. c, #1/0 Table 310.15(B)(7)

7. d, 80 Table 310.15(B)(3)(a)

8. d, 310.10(D)


CABINETS , CUTOUT BOXES AND METER SOCKET ENCLOSURES

ARTICLE 312

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the requirements applying

to installation and construction specifications of cabinets, cutout boxes, and meter socket enclosures.

MATERIALS:

Samples of the enclosures for use in a damp or wet location. Handouts

or pictures showing the above.


Present requirements included in Section 312.2 as applies to installations in damp and wet locations.

Cover the requirements included in section 312.3 as they apply to cabinets that are placed in

walls of the various types of materials. The requirements for unused openings are covered

elsewhere in the Code 110.12(A) and need to be touched on lightly. Cover Section 312.4 for

repairing noncombustible surfaces.

The requirements included in Tables 312.6(A) and 312.6(B) are very important and should

be covered in detail. Show these Tables on overhead and explain.. Panelboards and other

types of overcurrent equipment are listed. The space requirements in these tables is

necessary to determine intended use of the equipment.

The requirements in Section 312.6(C) are important and emphasis should be placed on

protection of the cable sheath.

Briefly review required clearances to live parts.

APPLICATION:

If time will allow, let the class answer the questions on the worksheet.




CABINETS, CUTOUT BOXES, AND METER SOCKET ENCLOSURES

ARTICLE 312

LEVEL I

WORKSHEET

1. The cabinet for a flush panelboard installed in a non-combustible wall shall be installed no farther than which of the following from the wall surface?

a. 1/8 inch b. 1/2 inch

c. 3/8 inch d. 1/4 inch

2. Non-metallic cable (Type NM) is used for both the feeder and branch circuits for

a panelboard installation. Each cable is required by Code to be:

a. secured to the cabinet

b. secured within 12 inches of the cabinet

c. both a and b


3. Three 250 KCmil copper conductors enter a panelboard enclosure opposite their

termination point on the terminal of a circuit breaker. The minimum amount of wire bending space required for this panelboard is which of the following?

a. 2 1/2 inches

b. 4 1/2 inches

c. 5 inches

d. 9 inches

4. Three 250 KCmil conductors enter a panelboard enclosure at right angles to their

termination point on the terminal of a circuit breaker. The minimum amount of wire bending space required for this panelboard is which of the following?

a. 4 1/2 inches b. 5 inches

c. 8 inches

d. 10 inches


5. Noncombustible surfaces that are broken or incomplete shall be repaired so that there

are no gaps at the edge of a cabinet employing a flush type cover exceeding which

distance?

a. 4 mm

b. 6 mm

c. 1/8”

d. 1/16”


CABINETS, CUTOUT BOXES, AND METER SOCKET ENCLOSURES ARTICLE 312

LEVEL I

ANSWER KEY

1. d, 1/4 inch 312.3

2. c, both a and b 312.5(C) and 334.30

3. d Table 312.6(B)

4. c Table 312.6(A)

5. c, 1/8” 312.4


OUTLET, DEVICE, PULL AND JUNCTION BOXES, CONDUIT BODIES, FITTINGS, AND HANDHOLES ARTICLE 314 LEVEL I OBJECTIVE After completing this section the code official should be able to:

a. Identify the various types of boxes encountered in typical level 1 residential and small commercial installations,

b. Calculate minimum size for outlet boxes and conduit bodies based on the

number of conductors and devices installed

c. Evaluate installations for code compliant mounting of boxes and conduit bodies

Samples of various boxes and conduit bodies (if available) INTRODUCTION Review the scope of Article 314 and identify the type of boxes typically used in residential and small commercial installations. Identification of the various types of boxes and conduit bodies and as well as proper sizing of outlet and junction boxes including minimum dimensions of pull and junction boxes for conductors size #4 and larger will be discussed. This article also covers fittings used to connect raceways and cables to boxes and conduit bodies. PRESENTING THE LESSON Emphasize that the ability to apply the requirements of Article 314 for boxes and conduit bodies is an essential skill for a Level 1 code official. Article 314 covers the installation and use of all boxes and conduit bodies. Refer back to Section 300.15 as covered in a previous lesson for information on where boxes are required. If available provide samples of different types of boxes and conduit bodies. Remind course participants that requirements in other articles are also applicable to the installation of boxes and conduit bodies including Article 250 Grounding and Bonding. Cover the topics from the course outline as thoroughly as possible within the time allowed. Use in-class exercises to reinforce covered topics if time allows or provide exercises as handouts for home study.

In Class exercise

1) Assuming a 0.5 cubic inch plaster ring is installed, what is the minimum standard size metal switch box required to accommodate the conductors and devices in the diagram #1? Note: Standard NM cable connectors are installed with the clamping means outside of the box.


Solution: Refer to Table 314.16(A)

Begin with 314.16(B)(5): All equipment grounding conductors are connected together and

counted as a single conductor based on the largest equipment grounding conductor in the

group. In this case a #12 conductor. The required volume allowance for a #12 conductor is

2.25 cubic inches (Table 314.16(B). The required allowance for the equipment grounding

conductors is 2.25 cubic inches.

Section 314.16(B)(4) requires a double volume allowance for each device yoke containing

one or more devices. In this case we have two devices, a single pole switch and a duplex

receptacle. Each will require a double volume allowance based on the largest conductor

connected to the device. For the switch connected to the #14 conductors this would be 2 X

2 cubic inches for a total of 4.0 Cubic inches. The receptacle is connected to #12

conductors so the volume allowance for the receptacle is 2 X 2.25 cubic inches for a total of

4.5 cubic inches. Adding the 4.0 cubic inches required for the switch to the 4.5 cubic inches

for the receptacle gives a total volume allowance for the installed devices of 8.5 cubic

inches.

Section 314.16(B)(3): There are no luminaire studs or hickeys installed in this box.

Section 314.16(B)(2): There are 3 cable clamps installed, but the clamping means is located

outside of the box. No volume allowance is required.

NOTE: Review 2014 Code Change

Section 314.16(B)(1): There are three cables entering the box (one 14/2 with ground one

14/3 with ground and one 12/2 with ground). The equipment grounding conductors have

already been accounted for in step 1. The 14/2 cable counts as 2 conductors (2 X 2 cubic

inches equals 4 cubic inches). The 14/3 cable counts as 3 conductors (3 X 2 cubic inches

equals 6 cubic inches). The 12/2 cable counts as 2 conductors (2 X 2.25 cubic inches equals

4.5 cubic inches). There is also a short # 14 pigtail connected to the switch. This conductor

does not have to be counted since no part of the conductor leaves the box. The total

conductor fill for this box is then 4 + 6 + 4.5 = 14.5 cubic inches.

The total volume required for the box is the sum of 2.25 (eq. grounds) + 8.5 (devices) +

14.5 = 25.25 cubic inches. The plaster ring provides 0.5 cubic inches of the total required

which leaves 24.75 cubic inches required for the box.

A 4 inch square by 2-1/8 deep metal box (30.3 cu. in.) is sufficient per Table 314.16(A).

Discuss other possible box/plaster ring combinations that could meet the minimum

required volume.


OUTLET, DEVICE, PULL AND JUNCTION BOXES, CONDUIT BODIES, FITTINGS AND HANDHOLES ARTICLE 314

LEVEL I

WORKSHEET

1. Under which of the following conditions does the code permit an 8 inch x 8 inch non-metallic box to be used with electrical metallic tubing.

a. with an internal equipment bonding jumper between all entries b. with a proper seal around the conduit

c. with a round opening type box

d. with a rectangular type box with threaded openings

2. Which of the following boxes are considered conduit bodies?

a. FD boxes

b. FS boxes c. Type LB conduit fittings

d. All of the above

3. The maximum number of #14 conductors in a 4 inch x 1 1/2 inch square is?

a. 6

b. 8

c. 10

d. 12

4. What is the minimum size standard metal device box for 2 #14/2 AWG non-metallic

sheathed cables, 2 cable clamps and two (2) devices on one strap?

a. 3 x 2 x 2 3/4

b. 3 x 2 x 2 1/2

c. 3 x 2 x 1 1/2

d. 3 x 2 x 3 ½

5. What is the minimum distance the sheath of a non-metallic sheathed cable shall extend into a box?

a. 1 inch

b. 1/2 inch c. 1/4 inch

d. 1/8 inch


6. What is the maximum opening permitted around boxes in drywall?

a. 1 inch

b. 1/ 2 inch

c. 1/4 inch

d. 1/8 inch

7. Boxes mounted in non-combustible walls shall be installed so that the front edge will be flush or set back no more than:

a. 1 inch b. 1/2 inch

c. 1/4 inch

d. 1/8 inch

8. Screws, used for the support of a device box, shall not be permitted to pass

through the box unless which of the following occurs?

a. They pass through the interior of the box 1/2 inch from the back. b. The exposed threads in the box are covered by approved means.

c. The box is a non-metallic box with a rectangular opening. d. The box is a metallic box with a rectangular opening.

9. The minimum depth of a box when a flush device is supplied by #12 conductors is:

a. 1 inch

b. 15/16 inch

c. 1/2 inch

d. 3/4 inch

10. A looped, unbroken conductor not less than twice the minimum length

required for free conductors in 300.14 shall count as which of the following

number of conductors when passing through a box.

a. 1

b. 2

c. 3

d. 0


OUTLET, DEVICE, PULL AND JUNCTION BOXES, CONDUIT BODIES, FITTINGS, AND

HANDHOLES

ARTICLE 314

LEVEL I

ANSWER KEY

1. a. 314.3 Exception 1

2. c 314.1

3. c, 10 Table 314.16(A)

4. d, 3 x 2 x 3 1/2 Table 314.16(A)

5. c, 1/4 inch 314.17(C)

6. d, 1/8 inch 314.21

7. c, 1/4 inch 314.20

8. b 314.23(B)(1)

9. b, 15/16 inch 314.24(B)(4)

10. b, 2 314.16(B)(1)


ARMORED CABLE

ARTICLE 320

LEVEL I

OBJECTIVE:


requirements for the installation of Type AC cable.

MATERIALS NEEDED:

Sample of different types of Armored Cable.

INTRODUCTION:

This Article covers the use and installation requirements for a fabricated assembly of

insulated conductors in a flexible metallic enclosure. Note the differences between Type

AC and Type MC cable assemblies.


Cover the permitted uses and uses not permitted for Type AC cable. Note the

requirements for supporting, bending, terminating and installation in accessible attics

and through studs, joists and rafters. Type AC cable shall provide an adequate path for

fault current as required by 250.4(A)(5) or (B)(4) to act as an equipment grounding

conductor. Note the bond wire in Type AC cable is in constant contact with metal

armor. The bond wire and the cable armor together constitute a single equipment


APPLICATION:





ARMORED CABLE

ARTICLE 320

LEVEL I

WORKSHEET

1. In general, type AC Cable shall be supported at intervals not exceeding which of the

following?

a. 3 feet

b. 4 -1/2 feet

c. 6 feet

d. 5 feet

2. Where in accessible attics Type AC cable is run across the top of floor joists or within

7 feet of the floor on the face of a studded rafter the cable shall be protected by

substantial guard strips which are at least:

a. As high as the box the cable is attached to.

b. As high as the cable.

c. At least 1-1/2 inches high.

d. At least 3 inches high.

3. Type AC cable is not permitted to be used in which of the following?

a. in damp or wet locations

b. both exposed and concealed work

c. dry locations

d. in cable trays

4. The ampacity of Type AC cable installed in thermal insulation shall be that of


a. 40º C

b. 60º C

c. 90º C

d. 110º C

5. A 12/3 copper Type AC cable with individual conductors rated 90C is run through

thermal insulation. The allowable ampacity of the conductors is:

a. 15 Amperes

b. 20 Amperes

c. 25 Amperes

d. 30 Amperes


117

ARTICLE 320

LEVEL I

ANSWER KEY

1 . b 320.30

2 . b 320.23(A) 3 . a 320.12

4 . b 320.80

5 . b 320.80/310.15(B)16


FLAT CABLE ASSEMBLIES: TYPE FC

ARTICLE 322

LEVEL I

OBJECTIVE:


requirements for the installation of Type FC cable.

MATERIALS NEEDED:

Show samples of different types of Flat Cable Assemblies, (if available).

INTRODUCTION:

This article covers the use, installation, and construction specifications for flat cable

assemblies, Type FC.


Cover the permitted uses and uses not permitted for Type FC cable. Note the

requirements for securing and supporting. Type FC cable shall be formed to provide a

suitable insulation covering all the conductors and using one of the materials recognized

in Table 310.13(A) for general branch-circuit wiring. Type FC cable shall have the

temperature rating durably marked on the surface at intervals not exceeding 24 in. Note

that the grounded conductor shall be identified throughout its length by means of a

distinctive and durable white or gray marking. Point out the informational note

following Section 322.120(B). The color gray may have been used as an ungrounded

conductor in the past.

APPLICATION:






ARTICLE 322

LEVEL I

WORKSHEET

1. Flat cable assemblies shall have conductors of

a. # 16 AWG spiral stranded copper conductors.

b. # 12 AWG single stranded copper wires.

c. # 14 AWG special stranded conductors.

d. # 10 AWG special stranded copper wires.

2. Flat cable assemblies shall consist of which of the following?

a. Two conductors.

b. Three or four conductors.

c. Four or five conductors.

d. Two, three, four, or five conductors.

3. Type FC cable shall have the temperature rating durably marked on the surface at intervals

not exceeding

a. 24 inches

b. 36 inches

c. 48 inches

d. 18 inches



ARTICLE 322

LEVEL I

ANSWER KEY

1. d, # 10 AWG special stranded copper wires 322.104

2. d, Two, three, four, or five conductors 322.100

3. a, 24 inches 322.120(A)


FLAT CONDUCTOR CABLE: TYPE FCC

ARTICLE 324

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar

with the requirements for the installation of Type FCC systems.

MATERIALS NEEDED:

Sample of Flat Conductor Cable (if

available). INTRODUCTION:

This article covers the use, installation, and construction specifications

for flat conductor cable Type FCC.


Cover the permitted uses and uses not permitted for Type FCC systems.

Note the requirements for securing and supporting. Type FCC cable shall be

listed. Type FCC systems shall be permitted both for general-purpose and

appliance branch circuits and for individual branch circuits. General-purpose

and appliance branch circuits shall have ratings not exceeding 20 amperes.

Individual branch circuits shall have ratings not exceeding 30 amperes. FCC

systems shall be permitted on hard, sound, smooth, continuous floor

surfaces made of concrete, ceramic, or composition flooring, wood, and

similar materials as well as wall surfaces in surface metal raceways. All

receptacles and connections shall be constructed and installed so as to

maintain proper polarization of the system.

APPLICATION:

If time will allow, let the class answer the questions on the

worksheet. CHECKING AND FOLLOW-UP:



FLAT CONDUCTOR CABLE: TYPE

FCC ARTICLE 324

LEVEL I

WORKSHEET

1. FCC general-purpose and appliance branch circuits shall have ratings not

exceeding which of the following?

a. 15 amperes.

b. 30 amperes

c. 20 amperes

d. 25 amperes

2. FCC systems may be used in which of the following locations:

a. Outdoors or in wet locations

b. Damp locations

c. In any hazardous (classified) location

d. In residential, school, and hospital buildings

3. Floor-mounted Type FCC cable, cable connectors, and insulating ends shall be

covered with carpet squares not larger than

a. 39.37 inches square.

b. 24 inches square

c. 36 square inches

d. 48 square inches


FLAT CONDUCTOR CABLE: TYPE FCC ARTICLE 324

LEVEL I

ANSWER KEY

1. c, 20 amperes 324.10(2)

2. b, damp locations 324.10(E)

3. a, 39.37 inches square 324.41


METAL-CLAD CABLE: TYPE MC

ARTICLE 330

LEVEL I

OBJECTIVE:


requirements for the installation of type MC cable.

MATERIALS NEEDED:

Samples of different types of MC Cable

INTRODUCTION:

This article covers the use and installation of MC cable. The cable is a fabricated

assembly of insulated conductors in a flexible metallic enclosure.


Cover the uses permitted and the uses not permitted for MC cable. MC cable is widely

used without many limitations. Cover support requirements with exceptions. Fittings for

MC cable should be listed and identified for use with MC cable. In wet locations note the

requirement for a corrosion-resistant jacket to be provided over the metallic sheath.

APPLICATION:



If time will allow, correct the worksheet and discuss the results.



ARTICLE 330

LEVEL I

WORKSHEET

1. Type MC cable shall be supported and secured at intervals not exceeding ___?

a. 3’

b. 4’

c. 4 1/2’

d. 6’

2. MC installed through joist, studs, rafters must be spaced _______ from face of

structural member.

a. 1”

b. 1 1/4”

c. 1 1/2”

d. 1 3/4”

3. Type MC cable shall not be used in which of the following?

a. in concrete

b. outdoors

c. direct buried where identified for such use

d. on services

4. Minimum copper conductor size shall be?

a. 14 Al

b. 18 Cu

c. 10 Al

d. 16 Cu

5. Type MC Cable shall be permitted to be unsupported where the cable is not

greater in length from a fixture connection than which of the following?

a. 2 feet

b. 4 feet

c. 6 feet

d. 8 feet



ARTICLE 330

LEVEL I

ANSWER KEY

1. d, 6’ 330.30

2. b, 1 1/4” 330.17

3. a, in concrete 330.12

4. b, 18 Cu 330.104

5. c, 6 feet 330.30


NONMETALLIC-SHEATHED CABLE: TYPES NM, NMC AND NMS

ARTICLE 334

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be acquainted with the use,

installation and construction specifications of non-metallic sheathed cable.

MATERIALS:

Sample of NM cable, NMC cable.

Handouts and/or pictures of the above.

INTRODUCTION:

Nonmetallic-sheathed cable is a factory assembly of two or more insulated conductors having

an outer sheath of moisture-resistant material. There are three types of nonmetallic-sheathed

cables: NM, NMC and type NMS. In addition to the provisions of Article 334, non-metallic

sheathed cable shall be installed to comply with other applicable provisions of the Code

especially Articles 300 and 310.


Both types NM and NMC cables can be used in one, two, and multi-family dwellings

and other structures. NM cable can be used for both exposed and concealed work in

dry locations. It can be installed or fished in air voids in masonry walls that are not

subject to excessive moisture or dampness.

NMC cables can be used for both exposed and concealed work in dry, moist, damp, or

corrosive locations. It can be used in outside and inside masonry walls. It can be used in a

shallow chase in masonry, concrete, or adobe and covered with plaster, adobe, or similar

finish.

Both types NM, NMC and NMS shall not be used:

1. In any dwelling or structure not specifically permitted in 334.10(1), (2), and (3)

Exception: Type NM, NMC, and NMS cable shall be permitted in Type I and II construction

when installed within raceways permitted to be installed in Type I and II construction.

2. Exposed in dropped or suspended ceilings in other than one- and two-family and

multifamily dwellings

3. As service-entrance cable

4. In commercial garages having hazardous (classified) locations as defined in 511.3

5. In theaters and similar locations, except where permitted in 518.4(B)


6. In motion picture studios

7. In storage battery rooms

8. In hoistways or on elevators or escalators

9. Embedded in poured cement, concrete, or aggregate

10. In hazardous (classified) locations, except where permitted by the following:

a . 501.10(B)(3)

b . 502.10(B)(3) c . 504.20

In exposed work non-metallic sheathed cable shall closely follow the surface of

the building finish or of running boards. It shall be protected from physical

damage when necessary. When passing through a floor the cable shall be

enclosed in a metal pipe extending at least 6 inches above the floor. Where run at

angles with joists in unfinished basement cable can be secured directly to the

lower edges of the joists when not smaller than two #6 or three #8. Smaller cables

shall either be run through bored holes in joists or on running boards. In

accessible attics cables run across the top of floor joists or within 7 feet of floor

joists run across the face of rafters on studs shall be protected by guard strips at

least as high as the cable. Where run along the sides of rafters, studs, or floor

joists, neither guard strips nor running boards are required. Where attic space is

not accessible by permanent stairs or ladders protection is only required within 6

feet of the nearest edge of the scuttle hole. The cable shall be protected as

required in Section 300.4 where installed through studs, joists, rafters, and similar

members.

Wiring devices with integral enclosures identified for such use shall be permitted

as provided in 300.15(E).

The insulated conductors shall be rated at 90 degrees Celsius and be one of the

types listed in Table 310.13 which is suitable for branch-circuit wiring or one

which is identified for use in NM, NMC or NMS cables. The size conductors shall

be sized #14 through 2 copper or sizes #12 through 2 aluminum or copper-clad

aluminum. In addition to the insulated conductors, the cable can have an insulated

or bare equipment grounded conductor sized in accordance with Article 250. As

stated before, the conductors shall be rated 90 degrees Celsius but the cable itself

ampacity shall be that of 60 degrees Celsius conductors.

APPLICATION:


CHECKING AND FOLLOW UP :



NONMETALLIC-SHEATHED CABLE: TYPES NM, NMC AND NMS

ARTICLE 334

LEVEL I

WORKSHEET

1. NM cable shall be permitted to be used in which of the following?

a. one-and-two family dwellings

b. multi-family dwellings

c. other structures

d. all of the above

2. Type NMC cable shall not be permitted for which of the following?

a. In any dwelling or structure not specifically permitted

b. Exposed in dropped or suspended ceilings in other than one- and two-

family and multifamily dwellings

c. As service-entrance cable

d. All of the above

3. Where passing through a floor in exposed work, NM cable shall be enclosed in

metal pipe extending at least which of the following distances above the floor?

a. 2 inches

b. 4 inches

c. 8 inches

d. 6 inches

4. Which of the following statements about NM cable in unfinished basements is/are

correct?

(A) two No. 6 cable can be secured directly to the lower edge of a joist.

(B) two No. 8 cable can be secured directly to the lower edge of a joist.

a. A only

b. both A and B

c. B only

d. neither A nor B


5. Which of the following statements about bends in NM cable is/are correct?

(A) A run of cable between outlet and outlet, fitting and fitting, or outlet and

fitting shall not contain more than the equivalent of four quarter bends (360

degrees total).

(B) No bend shall have a radius less than six times the diameter of the cable.

a. A only

b. B only

c. both A and B

d. neither A nor B

6. Unless fished, NM cable shall be supported at intervals not exceeding which of the

following?

a. 4 feet

b. 4 1/2 feet

c. 6 feet

d. 3 feet

7. The maximum size 600 Volt NM cable is not greater than which of the following?

a. # 14 AWG

b. # 4 AWG

c. # 3 AWG

d. # 2 AWG

8. The overall covering of NM cable shall be which of the following?

a. flame-retardant

b. weather-resistant

c. fungus-resistant

d. corrosion-resistant

9. The ampacity of the insulated conductors in NM cable shall be which of the

following?

a. 60º C

b. 90º C

c. 75º C

d. 40º C


10. Where more than 2 NM cables containing 2 or more current-

carryingconductors are bundled together and pass through wood framing

that is to be fire- or draft-stopped using thermal insulation or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance

with which of the following?

a. Table 310.15 (B)(2)(a)

b. Table 310.16

c. Table 310.15 (B)

d. Table 310.15 (C)(3)

2014 NEC Instructor Manual and Student Worksheets -- Level

1 132

NONMETALLIC-SHEATHED

CABLE: TYPES NM, NMC AND

NMS ARTICLE 334

LEVEL I

ANSWER KEY

1. d, all of the above 334.10

2. d. all of the above

334.12(A)

3. d

334.15(B)

4. a, A only

334.15(C)

5. d, neither A nor B 334.24

6. b, 4 1/2 feet 334.30

7. 2 334.104

8. a, flame-resistant

334.116(A)

9. a, 60º C 334.80

10. c. 334.80


SERVICE-ENTRANCE CABLE: TYPES SE AND USE

ARTICLE 338

LEVEL I

OBJECTIVE:


construction and restrictions in the use of service-entrance cables Type SE and Type

USE.

MATERIALS NEEDED:

Samples of types SE and USE cables.


A service-entrance cable is a conductor assembly provided with a suitable overall

covering, primarily used for service of the following types:

a. Type SE service-entrance cables shall be permitted in wiring systems

where all of the circuit conductors of the cable are of the thermoset or

thermoplastic type.

b. Type USE, having a moisture-resistant covering and recognized for

underground use.

Certain constructions do not require an outer overall covering.

a. Cabled single-conductor Type USE that has a bare copper conductor cabled with

the assembly.

b. Type USE single, parallel, or cabled conductor assemblies that have a bare

copper concentric conductor applied.

If you have two or more of either SE or USE cables, one shall be permitted to be

uninsulated. Review Article 230 for uses of service-entrance cable for conductors.

Where all circuit conductors of Type SE cable are of rubber-covered or

thermoplastic type, then the cable may be used in interior wiring systems.

Type SE cables without individual insulation on the grounded circuit conductor

shall not be used as a branch circuit or as a feeder in a building unless certain

specifications are met.


Type SE cable shall not be subject to temperatures in excess of the specified

temperature requirement for a particular type of insulation.

If Type SE cable is used for interior wiring it must comply with provisions of Article 338

and cables must comply with provisions of Part II of Article 334 excluding 334.80.

If cables are installed through studs, rafter, joists, etc. they are subject to provisions of

Section 300.4.

Sections 310.15 (A) 3 and338.120 contain information on temperature limitations

of conductors and marking procedures for service-entrance cables.

APPLICATION:





SERVICE ENTRANCE CABLE: TYPES SE AND USE

ARTICLE 338

LEVEL I

WORKSHEET

1. Type SE cable has which of the following type cable coverings?

a. flame-retardant

b. moisture-resistant

c. Both of the Above

d. Neither of the above

2. Which of the following type cables is identified for underground use?

a. SER

b. SE

c. RHW

d. USE

3. Type SE service-entrance cable shall be permitted for use where the insulated

conductors are used for circuit wiring and the uninsulated conductor is used only

for which of the following?

a. Equipment grounding purposes.

b. Grounding electrode conductor.

c. Grounded electrode conductor.

d. Ungrounded conductor.

4. Bends in Types USE and SE cable shall be so made that the cable will not be

damaged. The radius of the curve of the inner edge of any bend, during or after

installation, shall not be less than which of the following?

a. 6 times the diameter of the cable.

b. 5 times the diameter of the cable.

c. 4 times the diameter of the cable.

d. 3 times the diameter of the cable.


SERVICE ENTRANCE CABLE: TYPES SE AND USE ARTICLE 338

LEVEL I

ANSWER KEY

1. c, both of the above 338.2

2. d, USE 338.2

3. a, equipment grounding purposes 338.10 (B)(2)

4. b. five times the diameter 338.24


UNDERGROUND FEEDER AND

BRANCH-CIRCUIT CABLE: TYPE UF

ARTICLE 340

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the use and application

of type UF cable.

MATERIALS NEEDED: Sample

of UF cable.

INTRODUCTION:

As the title of Article 340 (Underground Feeder and Branch Circuit Cable) implies, UF

cable has been tested and approved for direct burial application. UF cable is a factory

assembled cable of one or more moisture resistant cables with a flame-retardant,

moisture-, fungus-, and corrosion-resistant covering. See Table 310.15 (A) 3 for

temperature limitations.

This cable is similar in construction to NM cable and can be installed as NM cable

subject to the provisions of Article 334. UF cable is primarily utilized as feeders or

branch circuits to small detached structures or branch circuits for landscape lighting and

similar equipment.


The students should be instructed to review Article 340 in its entirety. The instructor

should review the Article with particular emphasis to allowable uses and prohibited uses of

UF cable. After the course presentation, the students should complete the following test.

Questions repeatedly missed should alert the instructor to material warranting additional

instruction.

APPLICATION:





UNDERGROUND FEEDER AND

BRANCH-CIRCUIT CABLE: TYPE UF

ARTICLE 340

LEVEL I

WORKSHEET

1. UF cable shall utilize conductors of size:

a. #14 AWG through #10 AWG, aluminum, copper, or copper-clad

b. #14 AWG copper, #12 AWG aluminum or copper-clad through #4/0 AWG

c. recognized by Table 310-16

d. not larger than #4 AWG

2. UF cable shall not be permitted in all the following except:

a. as service entrance cable to detached structures

b. in agricultural buildings

c. in residential dwellings not exceeding five floors above grade

d. in commercial garages

3. The ampacity of UF cable shall be that of:

a. 90 degree Celsius conductors per Section 310.16

b. 60 degree Celsius conductors per Section 310.16

c. 60 degree Celsius conductors per Section 310.15

d. 90 degree Celsius conductors per Section 310.15

4. UF cable embedded in concrete shall:

a. be concrete-tight type

b. be listed for type application

c. not be permitted except per Article 424.43

d. be encased in not less than 2 inches

5. UF cable sheath shall be:

a. fungus resistant

b. UV resistant

c. heat resistant

d. flame proof


6. The insulation of Type UF cable when used as NM cable shall be that of:

a) 60 degrees Celsius

b) 90 degrees Celsius

c) 60 degrees Fahrenheit

d) 140 degrees Hahrenheit

UNDERGROUND FEEDER AND BRANCH-

CIRCUIT CABLE: TYPE UF ARTICLE 340

LEVEL I

ANSWER KEY

1. b, #14 AWG copper, #12 AWG aluminum or

copper-clad through #4/0 AWG 340.104


2. b, in agricultural buildings 340.12, 547.5

3. c, 60 degrees Celsius conductors

per Section 310-15 340.80

4. c, not be utilized 340.12(8)

5. a, fungus resistant 340.116

6. b 340.112


INTERMEDIATE METAL CONDUIT: TYPE IMC

ARTICLE 342

LEVEL I

OBJECTIVE:


installation, and construction specifications of intermediate metal conduit.

INTRODUCTION:

The instructor may want to integrate Articles 342, 344, and 358 into one unit for teaching

purposes. Intermediate metal conduit is a conduit in which the walls are thinner than rigid

metal but thicker than electrical metallic tubing (EMT). It has a circular cross section and

when used with proper fittings and couplings can be used for the installation of

conductors.

MATERIALS NEEDED:

Samples of intermediate metal conduit, various fittings and couplings, and

different types of straps.


Intermediate metal conduit can be used in all atmospheric conditions. To prevent

galvanic action all use of dissimilar metals shall be avoided except aluminum couplings

can be used. Intermediate metal conduit can be used as an equipment grounding

conductor. (342.10, 342.14 and 342.60)

When subject to severe corrosive installations, it must be protected or suitable for the

condition. (342.10 (B))

When used in cinder fill, it must be either by a layer of non-cinder fill concrete or all

sides at least 2 inches thick or be not less than 18 inches deep, or be suitably protected

against corrosion. (342.10 (C))

When used in wet locations, all bolts, straps, screws, etc. must be corrosion-

resistance or suitably protected. (342.10 (D))

The minimum size that can be used in 1/2 trade size and the maximum is 4 inches trade

size. (342.20)

When the conduit has to be field cut, the ends must be reamed to remove the rough edges.

When field threading is required, a standard cutting die of 3/4 inches per taper foot shall

be used. (342.28)


IMC shall be installed as a complete system in accordance with 300.18 and shall

be securely fastened in place and supported in accordance with 342.30(A) and

(B).

Running threads shall not be used to connect couplings. Couplings shall be made

up tight and must be approved for conditions. (342.42)

When bends are needed, they must be made so as not to damage the wire to be

pulled inside the conduit by reducing the size or causing crimps. The radius must

meet the same requirements as rigid metal conduit. (342.24) Bends in one run of

intermediate conduit must not exceed 360 degrees. (342.26)

Supports must be installed within 3 feet of each box or fitting and at least every

10 feet. Where straight runs are used with threaded couplings and supports

prevent stress, then supports can meet requirements for rigid metal conduit.

Where in industrial uses from machinery, and vertical risers with threaded

couplings are used firmly supported at top and bottom and no other means of

support is available the distance can be increased to 20 feet. (342.30 (B) 3)

Intermediate metal conduit shall be installed as a complete system as provided in

Article 300.18 and shall be securely fastened in place. Conduit shall be supported

at least every 10 feet (3.05m). In addition, conduit shall be securely fastened

within 3 feet (914 mm) of each outlet box, junction box, device box, cabinet,

conduit body, or other conduit termination. Fastening shall be permitted to be

increased to a distance 5 feet (1.52 m) where structural members do not readily

permit fastening within 3 feet (914 mm). (342.30 (A&B))

Splices shall only be made in accordance with 300.15. (342.56)

A bushing shall be used when entering a box unless the design of the box

provides equal protection. (342.46) Remind them to look at footnote

under 300.4(G)

Intermediate metal conduit shall be in standard lengths of 10 feet with one

coupling provided with each length. The letters IMC shall be durably marked

every five feet. (342.Part III)

APPLICATION:






ARTICLE 342

LEVEL I

WORKSHEET

1. Minimum size of intermediate metal conduit is:

a. l/2 inches

b. 3/4 inches

c. l l/2 inches

d. 2 inches

2. Maximum size of intermediate metal conduit is:

a. 1 1/2 inches

b. 2 inches

c. 3 inches

d. 4 inches

3. When field threading intermediate metal conduit standard die with which of

following inches taper per foot must be used.

a. l/2

b. 3/4

c. l

d. 1 1/4

4. The number of bends shall not exceed:

a. 90

b. 180

c. 360

d. 200

5. Each run must be supported within what distance of the box.

a. 2 feet

b. 2 l/2 feet

c. 3 feet

d. 4 feet


6. Each 10 feet joint of intermediate metal conduit must be marked "IMC" at not less

than which of the following?

a. 2 feet

b. 5 feet

c. 3 feet

d. 4 feet

7. Cables shall be permitted to be installed in IMC in which of the following?

a. as long as a 20% fill is not exceeded.

b. only on industrial projects.

c. only if the cables do not exceed three conductors. d. where such use is not prohibited by the respective cable articles


145


ARTICLE 342

LEVEL I

ANSWER KEY

1. a, 1/2 inches 342.20(A)

2. d, 4 inches 342.20(B)

3. b, 3/4 inches 342.28

4. c, 360 degrees 342.26

5. c, 3 feet 342.30(A)

6. b, 5 feet 342.120

7. d 342.22


RIGID METAL CONDUIT: TYPE RMC

ARTICLE 344

LEVEL I

OBJECTIVE:


installation, and construction code requirements of rigid metal conduit.

MATERIALS:

Sample of rigid metal conduit and fittings.

INTRODUCTION:

Single family dwellings are seldom wired completely with rigid metal conduit because of

the high cost of such an installation; however, it is widely used in industrial plants.

Electrical metallic tubing is sometimes employed because the cost of labor for installation

is much less than for rigid conduit. The cost is still higher than for a cable type

installation. Sometimes rigid metal conduit is used for service raceway even though the

bulk of the installation is some other wiring method.

Industrial installations of rigid metal conduit have routinely presented electricians with jobs

of great proportions; however, with the hydraulic equipment in use today, this work is

easily accomplished. Various attributes of fluid or hydraulic power equipment recommend

it to the electrical industry. Hydraulic tools readily increase 100 pounds of applied effort to

200,000 pounds of output. This makes rigid metal conduit a lot easier to bend than the old

railroad track method.


Rigid metal conduit shall be permitted under all atmospheric conditions and occupancies. If

protected solely by enamel it is permitted only indoors where not subject to sever

conditions.

Where practicable, dissimilar metals on contact anywhere in the system shall be avoided

to eliminate the possibility of galvanic action. Aluminum and steel fittings and enclosures

shall be permitted to be used either steel or aluminum conduit. Rigid metal conduit and

associated fittings can be used in severe corrosive areas if protected by corrosion

protection and judged suitable for the condition.

Rigid metal conduit shall not be used in or under cinder fill where subject to

permanent moisture, unless suitable for the purpose, enclosed in a two inch


concrete envelope, or at least 18 inches under cinder fill. If

installed in a wet locations all support material shall be

protected against corrosion.

The minimum size conduit to be used shall be 1/2 inch

electrical trade size with the exception of 3/8 inch for enclosing

motor leads.

The number of conductors permitted in a single conduit shall

not exceed the percentage fill specified in Table 1 of Chapter 9.

The instructor should show an overhead of Table 9 and explain

how to interpret it.

All cut ends of rigid metal conduit shall be reamed to remove

rough edges. Where threaded, a standard cutting die with a

3/4 inch taper per inch shall be used. Where a conduit enters

a box or other fitting it shall be bushed with a bushing or

other approved means.

Running threads shall not be used at couplings. If threadless

couplings or connectors are used they shall be made tight and, if

used in masonry or concrete they shall be concrete tight type.

A run of conduit shall not contain more than the equivalent of 4

quarter bends total of 360 degrees. The radius of bends shall not

be less than shown in Tables Table 1, Chapter 9 for one shot

and full shoe benders or other bends.

Rigid metal conduit shall be supported within three feet of each

outlet box, junction box, cabinet, or fitting and no more than 10

feet apart. If threaded couplings are used, Table 344.30(B)(2),may

be used. Splices or taps shall be made only in junction boxes,

outlet boxes, or conduit bodies that comply with the applicable

provisions of Article 314.

Uses Permitted. Note the changes in 344.10 for the different

types of RMC such as Galvanized Steel and Stainless Steel

RMC, Red Brass RMC and Aluminum RMC.

Rigid metal conduit shall be installed as a complete system as

provided in Article 300 and shall be securely fastened in place

and supported in accordance with Article 344.30 (A) and (B).


Standard lengths of rigid metal conduit shall be ten feet including

one coupling. Other lengths can be shipped for specific applications

or uses. If made of corrosive resistant material the rigid metal

conduit shall have suitable markings. Each length shall be clearly

and durably identified in each ten feet.

APPLICATION:

If time will allow, let the class answer the questions on the

worksheet.





ARTICLE 344

LEVEL I

WORKSHEET

1. The use of dissimilar metals in contact in a rigid metal conduit system shall be

avoided to eliminate the possibility of which of the following?

a. Galvanic action.

b. Corrosion.

c. Electrolysis

d. Harmonics.

2. RMC shall be permitted to be installed in or under cinder fill where subject to

permanent moisture where protected on all sides by a layer of noncinder concrete

not less than which of the following?

a. 18 inches thick

b. 12 inches thick

c. 8 inches thick

d. 2 inches thick

3. Which of the two following statements is/are correct?

A. All screws holding supports for rigid metal conduit in a wet location

shall be made of corrosion-resistant materials.

B. In general, the minimum size conduit shall be 1/2 inch.

a. A only

b. B only

c. both A and B

d. neither A nor B


4. Which of the following is a condition which allows an exception to the minimum

size rigid metal conduit?

a. Underplaster extensions.

b. Motor lead enclosures.

c. Junction box connectors

d. Conduit connectors.

5. Conduit ends shall be reamed to remove which of the following?

a. paint

b. cutting oil

c. threads

d. rough edges

6. Where conduit is threaded in the field a standard cutting die with which of the

following requirements shall be used?

a. a 3/4 inch taper per foot

b. a 1/2 inch taper per foot

c. a 1/4 inch taper per foot

d. a 1 inch taper per foot

7. Bushings are required on conduit at junction boxes where design of box does not

offer equipment protection in order to provide for which of the following?

a. To prevent water infiltration.

b. To prevent corrosion of the wire.

c. To prevent abrasion of the wiring.

d. To strengthen the box-to-conduit connection.

8. Threadless couplings where buried in masonry shall be of which type?

a. watertight

b. airtight

c. sealed

d. concrete tight

9. Running threads shall not be used on conduit for which of the following reasons?

a. For connection at couplings.

b. For connections at junction boxes.

c. For bonding connectors to boxes.

d. For grounding conductors.


10. The minimum radius bend of a one inch rigid metal conduit for the installation of

THW conductors bent in the field with a one shot bender is which of the

following?

a. 5 1/2 inches

b. 5 3/4 inches

c. 6 inches

d. 11 inches

11. Which of the following statements about rigid metal conduit is correct?

A. The maximum number of bends permitted in one conduit run is four

quarter bends or total of 360 degrees.

B. Standard length shall be 5 feet.

a. A only

b. B only

c. both A and B

d. neither A nor B

12. The percentage fill of a 1/2 inch rigid metal conduit with 3 THW conductors will

be which of the following?

a. 60 percent

b. 40 percent

c. 75 percent

d. 80 percent

13. If structural members do not allow closer fastening, RMC shall be securely

fastened at junction boxes within which of the following?

a. 4 feet

b. 3 feet

c. 6 feet

d. 5 feet

14. RMC shall be permitted to be used as which of the following?

a. A grounded conductor.

b. An equipment grounding conductor.

c. A junction box.

d. An auxiliary gutter.

15. Red brass RMC shall be permitted to be installed for which of the following

types of applications?

2014 NEC Instructor Manual and

Student Worksheets -- Level 1

152

I. swimming pools

II. direct burial

a. I only

b. II only

c. Neither I or II

d. Both I and II



ARTICLE 344

LEVEL I

ANSWER KEY

1. a, galvanic action 344.14

2. d, 2 inches thick 344.10(C)

3. c, both A and B 344.10(D), 344.20(A)

4. b, motor lead enclosures 344.20 Exception

5. d, rough edges 344.28

6. a, 3/4 inch taper per foot 344.28

7. c, to prevent abrasion of the wiring 344.46

8. d. concrete tight 344.42(A)

9. a 344.42(B)

10. b, 5 3/4 inches Table 2, Chapter 9

11. a, A only 344.26

12. b, 40% Table 1 Ch. 9, 344.22

13. d, 5 feet 344.30(A)

14. b, an equipment grounding conductor 344.60

15. d, both I and II 344.10(2)


FLEXIBLE METAL CONDUIT: TYPE FMC

ARTICLE 348

LEVEL I

OBJECTIVE:

After completing this lesson, the students should be acquainted with the

construction and restrictions in the uses of Flexible Metal Conduit.

INTRODUCTION:

Flexible metal conduit is used in places requiring irregular bends or where flexibility is

required during or after installation. Trade sizes l/2" and larger may be installed in any

length, although supporting and grounding requirements vary depending on lengths

installed. Sizes of 3/8" have restricted uses in lengths not exceeding 6'.


The students should be instructed to review Article 348 in its entirety. The instructor

should review the Article with particular emphasis on usages, sizes, and grounding.

Samples can be utilized to familiarize the student with the construction and application

of flexible metal conduit. Show Table 348.22 and explain.

Flexible metal conduit shall be supported at intervals not exceeding 4 1/2" and within

12" of each outlet box unless fished, or length does not exceed 3' or being used in

lengths not exceeding 6' for a fixture tap.

Flexible metal conduit can be used as a grounding means according to 250.118 and

250.102(E). It shall be limited to lengths of 6' or less and overcurrent protection of 20

amps or less. Note the uses permitted in wet locations.

APPLICATION:






ARTICLE 348

LEVEL I

WORKSHEET

1. Flexible metal conduit of 3/8" trade size may be used for all of the following

except:

a. In lengths not exceeding 6' located in hoistways

b. In lengths not exceeding 6' for the connections to lighting fixtures.

c. Encased in concrete not over 4' in length

d. Manufactured wiring systems

2. The maximum number of #14 AWG type THHN conductors in 3/8" flexible metal

conduit with outside fittings is:

a. 7

b. 3

c. 2

d. 4

3. Flexible Metal Conduit is installed in accordance with 250.118(5) it shall be

allowed to be used an equipment grounding conductor when which of the

following occurs?

a. When flexibility is required.

b. When flexibility is not required.

c. When approved by the AHJ

d. Not allowed



ARTICLE 348

LEVEL I

ANSWER KEY

1. c, Encased in concrete not over 4' in length 348.20

2. d, 4 Table 348.22

3. b, Where flexibility is not required 348.60


LIQUIDTIGHT FLEXIBLE METAL CONDUIT: TYPE LFMC

ARTICLE 350 and

LIQUIDTIGHT FLEXIBLE NON-METALLIC CONDUIT: TYPE LFNC

ARTICLE 356

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the use and

construction of liquid tight flexible metal conduit and also with liquid-tight flexible

non-metallic conduit.

INTRODUCTION:

Before we can look at the use and application of liquid-tight, as it is referred to in the

trade, let's look at what it is. Liquidtight is a flexible conduit that is circular in cross

section with an outer covering that is non-metallic but an interior flexible metal core.

When used with proper couplings and fittings. It can be used for the installation of

conductors.

MATERIALS NEEDED:

This material is used extensively and should be covered thoroughly. Articles 348, 350

and 356 could be taught at the same time or in consecutive order. For this lesson, you

need samples of both liquid-tight flexible metal conduit and liquid-tight flexible non-

metallic conduit and their respective fittings and couplings.


Liquidtight flexible metal conduit, when listed and marked, can be used for both

concealed and exposed work, and for direct burial in earth where required for flexibility

or protection from liquids, vapors or solids. It can also be used for hazardous locations

where approved both by listing and by provisions of Article 500. It cannot be used

where subject to physical damage or to temperatures higher than what it has been tested

and approved for. (350.10, 350.12)

The minimum size of liquid-tight flexible metal conduit is 1/2" trade size unless 3/8"

meets the requirements for flexible metal conduit of 3/8" size. The maximum size is 4"

trade size.

The maximum number of conductors that can be installed must meet the

requirements for conduits in Table 1 of Chapter 9. Size 3/8" shall meet the

requirements of flexible metal conduit. (350.22)


When being used as a fixed raceway, liquid-tight flexible metal conduit shall be

supported every 4 1/2 feet and within 12" of each box, cabinet or fitting. The

exceptions to this is for fixture taps, lengths not exceeding 3 feet and at

terminations where flexibility is needed. Note the changes to the exceptions to in

350.30(A) (350.30)

When using liquid-tight flexible metal conduit as a grounding means, both the

conduit and fittings must be approved for grounding. If the conduit is 1 1/4" and

smaller and less than 6 feet in length, terminated in fittings approved for

grounding, and 1/2" and 3/8" is protected by 20 amp and 3/4" to 1 1/4" by 60

amps, then the conduit does not have to be approved for grounding. Where

connecting equipment, and flexibility is needed, a grounding conductor shall be

used. (350.60, 250.118)

Bends shall not exceed 360 degrees and angle connectors shall not be used in

concealed spaces. (350.26)

Liquidtight flexible non-metallic conduit differs from the metallic kind by having

an interior that is reinforced but non-metallic. It can be used in places where

liquid-tight flexible metal conduit can be used. If used outside it must be

approved for outside use. It is not approved for hazardous locations, and cannot

be used for conductors in excess of 600 volt nominal. (356.10, 356.12). Note

356.10 (4) Direct Burial.

Except for 3/8" motor leads, the minimum size of 1/2" trade size and the

maximum is 4" trade size. (356.20)

Discuss maximum supporting lengths. (356.30)

The equipment grounding conductor can be run inside or outside the raceway if

run outside the grounding conductor is limited to 6 feet in length. (356.60,

250.102)

APPLICATION:





LIQUIDTIGHT FLEXIBLE METAL CONDUIT: TYPE LFMC ARTICLE 350 and LIQUIDTIGHT FLEXIBLE NON-METALLIC CONDUIT: TYPE LFNC ARTICLE 356 LEVEL I WORKSHEET

1. The smallest size of liquid-tight flexible metal conduit that can be used without exception in normal circumstances is?

a. 3/8 inch b. 1/2 inch c. 3/4 inch d. 1 inch

2. Maximum size of liquid-tight flexible non-metallic conduit that can be used is?

a. 1 1/4 inches b. 1 1/2 inches c. 2 inches d. 4 inches

3. Liquidtight must be supported within which of the following distances of each fitting?

a. 12 inches b. 24 inches c. 36 inches d. 48 inches

4. Where flexibility is not required, LFMC shall be permitted in which of the following?

a. shall be permitted to be used in all sizes if conductors therein are protected at no greater than 70 amperes. b. shall be permitted to be used in any location. c. may be used in any location with an ambient temperature below 110 degrees F.

d. shall be permitted to be used as an equipment grounding conductor when installed in accordance with 250.118(6).


5. Liquidtight flexible non-metal conduit cannot be used in lengths of more than?

a .3 feet

b. 4 feet

c. 5 feet

d. any length


LIQUIDTIGHT FLEXIBLE METAL CONDUIT

ARTICLE 350 and

LIQUIDTIGHT FLEXIBLE NON-METALLIC CONDUIT

ARTICLE 356

LEVEL I

ANSWER KEY

1. b, 1/2 inch 350.20

2. d, 4 inches 356.20(B)

3. a, 12 inches 350.30(A)

4. d, 60 250.118(6), 350

5. d 350.60 (356.12 (3)


RIGID POLYVINYL CHLORIDE CONDUIT: TYPE PVC

ARTICLE 352

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be acquainted with the use, installation,

and construction specifications of rigid polyvinyl chloride conduit.

MATERIALS NEEDED:

Samples of various types of rigid polyvinyl chloride conduit.

Handouts and/or pictures of the above.

INTRODUCTION:

For use above ground, the material shall be resistant to moisture and chemical

atmospheres, it shall be flame-retardant, resistant to impact and crushing, resistant to

distortion from heat under conditions likely to be encountered in service and resistant to

low temperature and sunlight effects.

For use underground, the material shall be acceptably resistant to moisture and corrosive

agents and be of sufficient strength to withstand abase, such as by impact and crushing, in

handling and during installation. Where intended for direct burial without encasement in

concrete, the material shall also be capable of withstanding continued loading that is likely

to be encountered after installation.


Rigid polyvinyl chloride conduit shall be permitted to be used under the following

conditions:

1. concealed

2. in locations subject to severe corrosive influences as cited in Section 300.6

3. in cinder fill

4. in wet locations

5. in dry and damp locations

6. for exposed work

7. for underground installations

Rigid polyvinyl chloride conduit shall not be used:

1. in hazardous locations except as covered in Sections 503.3(A), 504.20, 514.8, 515.8,

and the exception to Section 501.4(B)

2. for support for fixtures or other equipment not described in 352.10(H)


3. where subject to physical damage


4. where subject to ambient temperatures exceeding those the conduit was

approved.

5. For conductors whose insulation temperature limitations would exceed those

for which the conduit is approved.

6. in theaters and similar locations except as provided in Article 518 and 520.

In addition to the requirements of Article 352, rigid polyvinyl chloride conduit

shall comply with the applicable provisions of Article 300. Where equipment

grounding is required by Article 250, a separate equipment grounding conductor

shall be installed in the conduit.

All cut ends of rigid polyvinyl chloride conduit shall be trimmed inside and

outside to remove the rough edges. All joints shall be made by an approved

method.

Rigid polyvinyl chloride conduit shall be securely fastened within 3 feet of each

box, cabinet, or other conduit termination and the maximum spacing between

supports shall be as shown in Table 352.30(B).

The minimum size rigid polyvinyl chloride conduit that can be used is 1/2 inch

electrical trade size. The number of conductors permitted in a conduit shall not

exceed the percentage fill as allowed in Table 1, Chapter 9.

Unless the design of the box or fitting is such to provide equivalent protection, a

bushing or adapter shall be used to protect conductors from abrasion where a

conduit enters a box or fitting.

Field bends in rigid polyvinyl chloride conduit shall be made only with bending

equipment identified for the purpose and the bend itself shall meet the

specifications of Table 2, Chapter 9.

The number of bends in one run of conduit shall not exceed the equivalent of four

quarter bends (360 degrees, total).

Each length of polyvinyl chloride conduit shall be clearly and durable marked

every 10 feet as required in Section 110.21.

APPLICATION:






ARTICLE 352

LEVEL I

WORKSHEET

1. Which of the following statements about rigid polyvinyl chloride conduit is correct?

A. it shall be made from rigid polyvinyl chloride (PVC) material only. B. it may be used in continuous lengths from a reel when listed for this

purpose.

a. A only

b. b only

c. both A and B

d. neither A nor B

2. All cut ends of PVC shall be required to meet the following?

a. trimmed inside

b. trimmed outside

c. have rough edges removed.

d. All of the above

3. Rigid polyvinyl chloride conduit may be used in locations subject to severe corrosive

influences as covered in which of the following sections?

a. Section 300.6.

b. Section 342

c. Section 352

d. Section 310.5

4. Which of the following statements about the permitted uses of rigid polyvinyl chloride

conduit is correct?

A. it may support fixtures and other equipment.

B. it may be run in cinder fill.

a. A only

b. B only

c. both A and B

d. neither A nor B


5. A 1 1/2 inch PVC conduit may have a radius bend not greater than which of the following if

other than a one-shot bend is used?

a. 8 3/4 inches b. 10 inches

c. 6 inches

d. 4 inches

6. Rigid polyvinyl chloride conduit shall be securely fastened within what distance

of each box, cabinet, or other conduit termination?

a. 4 feet

b. 5 feet

c. 6 feet

d. 3 feet

7. The percentage fill for a 3/4 rigid nonmetallic conduit containing three conductors is which

of the following?

a . 3 b . 31

c . 8

d . 40

8. The total number of bends permitted in one run of polyvinyl chloride conduit is

equivalent to:

a. four 45 degree bends

b. 180 degrees total

c. four quarter bends

d. three quarter bends

9. The maximum spacing between supports for rigid polyvinyl chloride conduit 6 inches in size is:

a. 3 feet

b. 6 feet

c. 8 feet

d. 10 feet


10. Rigid polyvinyl chloride conduit may be used in trade sizes not smaller than which of

the following?

a. trade size 3/8 inch b. trade size 3/4 inch

c. trade size 1/2 inch

d. trade size 5/8 inch

11. Where equipment grounding is required, which of the following is used?

a. A separate grounded conductor shall be installed. b. A separate grounding conductor shall be installed.

c. A separate bonding jumper shall be installed.

d. A separate equipment grounding conductor shall be installed.

12. Rigid polyvinyl chloride conduit shall be permitted to support polyvinyl chloride conduit bodies not larger than which of the following?

a. nonmetallic conduit bodies not larger than the largest trade size of an

entering raceway

b. nonmetallic conduit bodies not larger than 3/4 inch.

c. nonmetallic conduit bodies in corrosive circumstances.

d. Shall never be used to support conduit bodies.



ARTICLE 352

LEVEL I

ANSWER KEY

1. c, Both A&B 352.100

2. d. all of the above 352.28

3. a. 352.10(B)

4. b, B only 352.10(C), 352.12(B)

5. b Table 2, Chapter 9

6. d, 3 feet 352.30(A)

7. d, 40 352.22, Chap 9 Table 1

8. c, 360 degrees total 352.26

9. c, 8 feet Table 352.30(B)

10. c 352.20(A)

11. d, 352.60

12. a 352.10(H)


NONMETALLIC UNDERGROUND CONDUIT

WITH CONDUCTORS: TYPE NUCC

ARTICLE 354

LEVEL I

OBJECTIVE: After completing this lesson, each student should be acquainted

with the use, installation, and construction specifications of Nonmetallic

Underground Conduit with Conductors: Type NUCC

MATERIALS NEEDED:

Samples of various types of Nonmetallic Underground Conduit with Conductors:

Type NUCC conduit or if unavailable, handouts and/or pictures of the above.

INTRODUCTION:

NUCC is an assembly that is provided in continuous lengths shipped in a coil,

reel, or carton. The nonmetallic underground conduit shall be listed and

composed of a material that is resistant to moisture and corrosive agents. It shall

also be capable of being supplied on reels without damage or distortion and shall

be of sufficient strength to withstand abuse, such as impact or crushing, in

handling and during installation without damage to conduit or conductors. NUCC

shall be clearly and durably marked at least every 10 ft. as required by 110.21.

The type of conduit material shall also be included in the marking. Identification

of conductors or cables used in the assembly shall be provided on a tag attached

to each end of the assembly or to the side of a reel. Cover uses permitted as well

as uses not permitted.


NUCC is a factory assembly of conductors or cables inside a nonmetallic, smooth

wall conduit with a circular cross section. NUCC and associated fittings shall be

listed. NUCC and fittings shall be permitted for direct burial underground type

installation, encased or embedded in concrete or cinder fill, in underground

locations subject to severe corrosive influences where specifically approved for

this type of installation and aboveground, except as prohibited in 354.12, where

encased in not less than 2 inches of concrete. NUCC shall not be used in exposed

locations, inside buildings, or in any hazardous (classified) location, except as

permitted by other articles of this Code. Note the Exception for inside buildings to

the students.

APPLICATION:





NONMETALLIC UNDERGROUND CONDUIT WITH

CONDUCTORS: TYPE NUCC

ARTICLE 354

LEVEL I

WORKSHEET

1. NUCC shall be clearly and durably marked in accordance with which of the

following?

a. at least every 2 feet

b. at least every 30 inches

c. at least every 5 feet

d. at least every 10 feet

2. The radius of the curve of the centerline of a bend in a 1 inch NUCC conduit shall

not be less than which of the following?

a. 10 inches

b. 8 inches

c. 14 inches

d. 12 inches

3. When using NUCC where equipment grounding is required, which of the

following is to be used?

a. an assembly with a separate enclosure with a green or bare

wire

b. an assembly containing a separate equipment grounding

conductor.

c. a gutter assembly containing a separate grounding

conductor.

d. an equipment grounding conductor.


NONMETALLIC UNDERGROUND CONDUIT

WITH CONDUCTORS: TYPE NUCC

ARTICLE 354

LEVEL I

ANSWER KEY

1. d, 10 feet 354.10

2. c, 14 inches Table 354.24

3. b, an assembly containing separate equipment 354.60

grounding conductor .


ELECTRICAL METALLIC TUBING: TYPE EMT

ARTICLE 358

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be acquainted with the

construction and restriction in the uses of electrical metallic tubing.

MATERIALS:

Samples of electrical metallic tubing.

INTRODUCTION:

Electrical metallic tubing (EMT) sometimes called "thin-wall conduit" has a wall

thickness less than that of rigid conduit, and it bends more easily. It is connected with

compression or indentation-type fittings, since it is too thin to thread. A special tool is

used to install indentation fittings.


Electrical metallic tubing is installed and has the same use for both exposed and

concealed work as rigid conduit except it cannot be used where subject to severe physical

damage, or in hazardous locations. When used in wet locations or poured over in

concrete, fittings of the type to prevent water entering the conduit shall be used.

Tubing and fittings may be obtained, made of an alloy having corrosion-resisting

characteristics. This makes them especially suitable for use in many locations where

there are corrosive fumes, or excessive moisture.

No tubing shall be used smaller than 1/2 inch in diameter, electrical trade size, except for

under plastic extensions. The maximum size tubing shall be the 4-inch electrical trade

size. Bends in the tubing shall be made so that the tubing will not be injured and that the

internal diameter of the tubing will not be effectively reduced. One run of conduit shall

include not more than four "quarter" bends.

APPLICATION:

If time allows, let the class answer questions on the worksheet.

CHECKING AND FOLLOW UP :




ARTICLE 358

LEVEL I

WORKSHEET

1. Which of the following is a permitted use for Electrical Metallic Tubing?

a. Where, during installation or afterward, it will be subject to severe

physical damage.

b. Where protected from corrosion solely by enamel.

c. For the support of luminaires (fixtures) or other equipment except

conduit bodies no larger than the largest trade size of the tubing.

d. For both exposed and concealed work.

2. Electrical trade size tubing shall not be used smaller than which of the following?

a. 1 inch

b. 3/4 inch

c. 3/8 inch

d. 1/2 inch

3. Electrical trade size tubing shall not be used larger than which of the following?

a. 4 inch

b. 3 inch

c. 2 inch

d. 6 inch

4. The radius of the curve of any field bend to the centerline of 2 inch tubing using a

One Shot bender shall not be less than which of the following?

a. 10 inches

b. 9 1/2 inches

c. 8 1/4 inches

d. 7 1/4 inches

5. One run of conduit shall not include more than which of the following "quarter"

bends.

a. 6

b. 4

c. 3

d. 2



ARTICLE 358

LEVEL I

ANSWER KEY

1. d 358.10 (A)

2. d, 1/2 inch 358.20(A)

3. a 358.20(B)

4. b,91/2 inches Table 2, Chapter 9 pg. 625

5. b, 4 358.26


AUXILIARY GUTTERS

ARTICLE 366

LEVEL I

OBJECTIVE:


more important requirements related to auxiliary gutters.

INTRODUCTION:

Auxiliary gutters are permitted to supplement wiring spaces at meter

centers, distribution centers, switchboards, and similar points of wiring

systems and may enclose conductors or busbars, but shall not be used to

enclose switches, overcurrent devices, appliances, or other similar

equipment.


1. Metallic Auxiliary Gutter. A sheet metal enclosure used to supplement

wiring spaces at meter centers, distribution centers, switchboards, and

similar points of wiring systems.

2. The enclosure has hinged or removable covers for housing and

protecting electrical wires, cable, and busbars.

3. The enclosure is designed for conductors to be laid or set in place

after the enclosures have been installed as a complete system.

4. It is very important that the number and ampacity of conductors

contained within the gutters be understood.

5. Each installation of the subject equipment involves splices and taps.

Therefore the requirements in Section 366.56 are important.

6. Section 366.100 dealing with construction is primarily used by testing

labs to evaluate equipment for testing.

APPLICATION:

If time allows, let the class answer the questions on the

worksheet. CHECKING AND FOLLOW-UP:



AUXILIARY GUTTERS

ARTICLE 366

LEVEL I

WORKSHEET

1. Auxiliary gutters shall not extend beyond the equipment that it supplements a

distance greater than which of the following?

a. 10 feet

b. 20 feet

c. 30 feet

d. 15 feet

2. What is the maximum distance between the supports of auxiliary metal gutters?

a. 2 feet

b. 3 feet

c. 4 feet.

d. 5 feet

3. As a general rule, what is the maximum number of conductors permitted at any

cross section of an auxiliary gutter?

a. 15

b. 20

c. 25

d. 30

4. The sum of the cross-sectional areas of all contained conductors at any cross

section of a sheet metal auxiliary gutter shall not exceed what percent of the

interior cross-sectional area of the sheet metal auxiliary gutter?

a. 15

b. 20

c. 30

d. 40


AUXILIARY GUTTERS

ARTICLE 366

LEVEL I

ANSWER KEY

1. c. 30 feet 366.12

2. d. 5 feet 366.30

3. d. 30 366.22

4. a. 20% 366.22


MULTIOUTLET

ASSEMBLY ARTICLE

380

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be acquainted with the

requirements concerning the installations of multioutlet assembly.

MATERIALS NEEDED:

Samples of multioutlet assembly and fittings. Handouts of pictures of the

above.

INTRODUCTION:

This subject is not often common in level one jobs, so a limited amounted of

time should be spent on this subject. Multioutlet assembly is a type of

surface or flush raceway designed to hold conductors and receptacles. It can

be assembled in the field or at the factory.

PRESENTING THE LESSON: Discuss ultioutlet assembly.

Discuss where multioutlet assembly shall not be installed. [380.2(B)]

1. Where concealed, except that it shall be permissible to surround the back

and sides of a metal multioutlet assembly by the building finish or recess a

nonmetallic multioutlet assembly in a baseboard.

2. Where subject to severe physical damage.

3. Where the voltage is 300 volts or more between conductors unless the

assembly is of metal having a thickness of not less than .040 inch.

4. Where subject to corrosive vapors.

5. In hoistways.

6. In any hazardous (classified) location, except as permitted by other

articles of this Code.


APPLICATION:


CHECKING AND FOLLOW-UP.



MULTIOUTLET ASSEMBLY

ARTICLE 380

LEVEL I

WORKSHEET

1. Which of the following statements about multioutlet assembly is/are correct?

A. It can be installed in dry locations.

B. It can be installed in wet locations.

a. A only

b. B only

c. both A and B

d. neither A nor B

2. It shall be permissible to extend a metal multioutlet assembly through which of

the following?

a. walls

b. ceilings

c. floors

d. dry partitions

3. Multioutlet assembly can not be used where subject to which of the

following?

a. severe physical damage

b. hoistways

c. corrosive atmospheres

d. all of the above

4. Multi-outlet assembly shall not be used where the voltage is 300 volts or more

between conductors unless the assembly is of a metal having a thickness of not

less than which of the following?

a. .40 inches

b. .040 inches

c. .0040 inches

d. .04 inches


MULTIOUTLET ASSEMBLY

ARTICLE 380

LEVEL I

ANSWER KEY

1. a, A only 380.2(A)

2. d. dry partitions 380.3

3. d. all of the above 380.2(B)

4. b. .040


SURFACE METAL RACEWAYS

ARTICLE 386 and

SURFACE NONMETALLIC RACEWAYS

ARTICLE 388

LEVEL I

OBJECTIVE:


use, installation, and construction specifications of surface raceways.

MATERIALS NEEDED:

Samples of surface metal raceways.

INTRODUCTION:

In surface metal or aluminum raceway wiring, the wires are supported in a

thin metal casing. The raceway is installed exposed, being mounted on dry

walls, ceilings, and if approved, on floors. The sheet-steel casing called metal

raceway or metal molding is made with a flattened oval or rectangular cross

section. Most types of molding are made in two parts, a trough or base which

is snapped on the base. One type of metal surface raceway is manufactured

with the capping crimped on the base at the factory. With this type, the wires

must be pulled through the raceway from outlet to outlet as in the conduit-

wiring method. Provisions for outlets or switches are made by means of

special fittings inserted in the runs of molding. Surface nonmetallic raceways

are made of a suitable nonmetallic material that is resistant to moisture and

chemical atmospheres. It shall also be flame retardant resistant to impact and

crushing, resistant to distortion from heat under conditions likely to be

encountered in service and resistant to low-temperature effects.


Surface metal raceways shall be permitted in dry locations.

They shall not be used:

1. where subject to severe physical damage unless otherwise approved;

2. where the voltage is 300 volts or more between conductors unless the

metal has a thickness of not less than .040 inch;

3. where subject to corrosive vapors;

4. in hoistways;

5. concealed as permitted under raised floors.


The number and size conductors in both surface metal and nonmetallic raceways

shall be determined by what the raceways are designed for. Unbroken lengths of

surface metal and nonmetallic raceways shall be permitted to extend through dry

walls, dry partitions, and dry floors.

Where combination surface metal or nonmetallic raceways are used for signaling

and for lighting and power circuits, the different systems shall be run in separate

compartments identified by sharply contrasting colors of the interior finish or in

nonmetallic an identified printed legend. The same relative position of

compartments shall be maintained throughout the premises.

Splices and taps shall be permitted in surface metal and nonmetallic raceways

having a removable cover that is accessible after installation. The conductors,

including splices and taps shall not fill the raceway to more than 75 percent of its

area at that point. In raceways without removable covers, splices and taps shall be

made only in junction boxes. The use of surface nonmetallic raceways shall be

permitted in dry locations.

They shall not be used: (388.12)

1. where concealed [except 388.10(2)];

2. where subject to severe physical damage;

3. where the voltage is 300 volts of more between conductors, unless listed for

higher voltage;

4. in hoistways;

5. in any hazardous (classified) location except as permitted by this Code.

6. where subject to ambient temperature exceeding those for which it is listed;

7. for conductors whose insulation temperature exceeds the limitations for which

the raceway is listed.

Surface metal and nonmetallic raceways shall be of such construction as will

distinguish them from other raceways. The surface raceways and their elbows,

couplings, and similar fittings shall be designed that the sections can be

mechanically, and in surface metal raceway, electrically coupled together without

subjecting the wires to abrasion.

Where covers and accessories of nonmetallic materials are used on surface metal

raceways, they shall be identified for such use.

APPLICATION:






ARTICLE 386

and


ARTICLE 388

LEVEL I

WORKSHEET

1. Surface metal raceways shall be supported at intervals?

a. not exceeding 2 ft.

b. not exceeding 4 ft.

c. not exceeding 5 ft.

d. in accordance with the manufacturer's installation instructions.

2. When combination surface nonmetallic raceways are used both for signaling

and for lighting and power circuits, the different systems shall be run in

separate compartments identified by which of the following?

a. stamping, imprinting, or color coding of the interior finish.

b. stamping of the outer surface..

c. coloring of the outer surface.

d. imprinting of the outer surface.

3. The number of current carrying conductors permitted in a single surface metal

raceway shall not exceed which of the following?

a . 20

b . 30

c . 25

d . 40

4. The sum of the cross-sectional areas of all contained conductors does not exceed

which of the following percentage of the interior cross-sectional area of the

surface metal raceway?

a. 30 percent

b. 20 percent

c. 40 percent

d. 10 percent


5. Splices and taps shall be permitted in surface metal raceways having which of the

following?

a. A readily accessible removable cover after installation.

b. An accessible removable cover after installation.

c. A removable cover.

d. A listed readily removable cover.

6. When combination surface metallic raceways are used for both signaling and for

lighting and power circuits, the different systems shall be run in separate

compartments identified by which of the following?

a. stamping

b. imprinting

c. color coding

d. all of the above

7. Surface metal raceways and their elbows, couplings, and similar fittings shall be

so designed that the sections can be electrically and mechanically coupled together

without subjecting the wires to which of the following?

a. moisture

b. fumes

c. static electricity

d. abrasion

8. Which if the following statements about surface nonmetallic raceways is correct?

A. They shall not be used where concealed.

B. They shall not be used where the voltage exceeds listing of

equipment.

a. A only

b. B only

c. both A and B

d. neither A nor B

9. The number of conductors or cables installed in surface metal raceway shall

not be greater than which of the following?

a. The number determined by Table 1, Chapter 9.

b. The number determined by Table 310.16

c. The number for which the raceway is designed.

d. The number determined by percentage of free space.


10. Surface nonmetallic raceways shall be of such construction as will distinguish

them from which of the following?

a. other conduits

b. other wiring methods

c. other designs

d. other raceways

11. Surface nonmetallic raceways shall not be used in the following:

a. Where concealed, except as permitted in 388.10(2)

b. Where subject to severe physical damage

c. Where the voltage is 300 volts or more between conductors,

unless listed for higher voltage

d. all of the above

12. Surface nonmetallic raceway shall be permitted to pass transversely through

dry walls, dry partitions, and dry floors if which of the following occurs?

I. If the length passing through is unbroken.

II. Access to the conductors shall be maintained on both sides

of the wall, partition, or floor.

a. I only

b. II only

c. Both I and II

d. Neither I or II


187


ARTICLE 386

and


ARTICLE 388

LEVEL I

ANSWER KEY

1. d 386.30

2. a 388.70

3. b. 30 386.22(2)

4. b. 20 percent 386.22(3)

5. b. 386.56


7. d. abrasion 386.100

8. c, both A and B 388.12

9. c 386.22

10. d 388.100

11. d 388.12

12. c 388.10


CONCEALED KNOB-AND-TUBE WIRING

ARTICLE 394

LEVEL I

OBJECTIVES:

After completing this lesson, each student should be familiar with the:

1. The definition and use of knob-and-tube wiring.

2. The construction and restrictions in the use of knob-and-tube wiring.

MATERIALS NEEDED:

Sample of knobs, tubes, and flexible nonmetallic tubing. Handouts or pictures of the

above.

INTRODUCTION:

Concealed knob-and-tube wiring is a wiring method using knobs, tubes, and flexible

nonmetallic tubing for the protection and support of single insulated conductors

concealed in hollow spaces of walls and ceilings of buildings.

It shall be permitted to be used only for extensions of existing installations and

elsewhere only by special permission.

It shall not be used in (1) commercial garages, (2) theaters, (3) motion picture studios,

(4) hazardous locations, and (5) in the hollow spaces of walls, ceilings, and attics when

such spaces contain loose or rolled insulation material.

In this lesson we will learn the Code requirements for running extensions of existing

installations of concealed knob-and-tube wiring and if allowed by special permission.

Not much time should be spent on this because it is hardly ever used in practice.


Conductors shall be supported within 6 inches of each side of each tap or splice and at

intervals not exceeding 4 1/2 feet.

Where solid knobs are used, conductors shall be tied with tie wires having

insulation equal to that of the conductors.

Where it is impracticable to provide supports, conductors shall be permitted to be fished

through hollow spaces in dry locations, provided each conductor is individually enclosed

in flexible nonmetallic tubing that is in continuous lengths between supports, between

boxes, or between a support and a box.


Conductors shall be kept apart at least 3 inches and at least 1 inch from the

surface over which they pass. They shall be separated at least 2 inches from metal

conduit piping or other conducting material.

In unfinished attics and roof spaces, conductors shall be installed along the sides of or

through bored holes in floor joist studs and rafters. When run through bored holes in

spaces that are accessible by stairway or permanent ladder they shall be protected by

running boards to a height up to 7 feet.

Splices shall be soldered unless approved splicing devices are used.

APPLICATION:





CONCEALED KNOB-AND-TUBE WIRING

ARTICLE 394

LEVEL I

WORKSHEET

1. Concealed knob-and-tube wiring can be installed in a new single family residence by


a. Special permission.

b. Special application.

c. Special requirements.

d. Special needs.

2. Concealed knob-and-tube wiring can be used in which of the following?

a. commercial garages

b. theaters

c. motion picture studios

d. extension of existing installations

3. Where not accessible by stairway or permanent ladder, conductors shall be

installed along the sides of or through all of the following except?

a. Bored holes in floor joists.

b. Bored holes in masonry.

c. Bored holes in studs.

d. Bored holes in rafters.

4. The maximum support for conductors in knob-and-tube wiring is at intervals not to

exceed which of the following?

a. 2 feet

b. 4 feet

c. 4 1/2 feet

d. 5 feet

5. Where solid knobs are used, conductors shall be securely tied thereto by wires

having insulation of which of the following types?

a. Insulation with a greater value than the conductor.

b. Insulation with a lesser value than the conductor.

c. Insulation with a value of not less than 60º C.

d. Insulation with a value equivalent to the conductor.


6. When Knob and Tube wiring is installed, a clearance of not less than which of

the following shall be maintained between conductors?

a. 6 inches

b. 5 inches

c. 4 inches

d. 3 inches

7. Conductors passing through wood cross members in plastered partitions shall be

protected at least 3 inches beyond the wood member by which of the following?

a. noncombustible tubes

b. nonabsorbent tubes

c. insulating tubes

d. noncombustible, nonabsorbent, insulating tubes

8. Concealed knob-and-tube conductors shall be separated at least which of the

following distances from metal conduit?

a. 2 inches

b. 3 inches

c. 4 inches

d. 5 inches

9. Where run through bored holes, conductors in the joists and in studs or rafters

to a height of not less than 2.1 m (7 ft) above the floor or floor joists shall be

protected by which of the following?

a. Running boards extending 2 inches on each side of the wiring.

b. Running boards extending 3 inches on each side of the wiring.

c. Substantial covers of wood.

d. Running boards extending 1 inch on each side of the wiring.

10. Unless approved splicing devices are used, which of the following shall be done

to splices in knob and tube wiring?

a. Welding of all splices.

b. Soldering of all splices.

c. Supporting of all splices.

d. Sealing of all splices.


CONCEALED KNOB-AND-TUBE WIRING ARTICLE

394

LEVEL I

ANSWER KEY

1. a. special permission 394.10

2. d 394.12

3. b. 394.23(A)

4. c. 4 1/2 feet 394.30 (A)(2)

5. d. 394.30(B)

6. d. 394.19(A)

7. d. noncombustible, nonabsorbent, insulating tubes 394.17

8. a. 2 inches 394.19(C), 398.19

9. d. 1 inch running boards 394.23(A)

10. b. soldering 394.56


FLEXIBLE CORDS AND CABLES

ARTICLE 400

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the trade names,

construction and restrictions in the uses of flexible cords and fixture wires.

INTRODUCTION:

Flexible cords and cables have many uses, most of which are for temporary purposes.

There are certain times they can be utilized for special equipment. In discussing this

article, we will see when and where they can be used and how.


Review Table 400.4.

Briefly discuss the Table pointing out the different types and their construction.

Ampacity of flexible cables shall be according to Table 400.5(A)(1)-Ampacity of

Flexible Cords and Cables with More Than Three Current-Carrying Conductors shall be

according to Table 400.5(A)(2). Be sure to discuss the Notes to Tables since they

explain how to use each table.

Cords and cables rated 105°C shall use correction factors in the 90°C column of Table

310.15(B)(2)(a) for temperature correction

Cords and cables shall be marked by a tag on the carton or reel with information in

310.11(A). If of the type listed in Section 400.6, it shall be marked with type, size, and

number of conductors in intervals not to exceed 24 inches.

Reference 110.3(B)

Flexible cords shall be permitted to be used as: (400.7)

(1) Pendants.

(2) Wiring of luminaires.

(3) Connection of portable luminaires, portable and mobile signs, or appliances.

(4) Elevator cables.

(5) Wiring of cranes and hoists.

(6) Connection of utilization equipment to facilitate frequent interchange.

(7) Prevention of the transmission of noise or vibration.

(8) Appliances where the fastening means and mechanical connections are specifically

designed to permit ready removal for maintenance and repair, and the appliance is

intended or identified for flexible cord connection.


(9) Connection of moving parts.

(10) Where specifically permitted elsewhere in this Code.

(11) Between an existing receptacle outlet and an inlet, where the inlet provides power to

an additional single receptacle outlet. The wiring interconnecting the inlet to the single

receptacle outlet shall be a Chapter 3 wiring method. The inlet, receptacle outlet, and

Chapter 3 wiring method, including the flexible cord and fittings, shall be a listed

assembly specific for this application.

Flexible cords and cables shall not be used:

(1) As a substitute for the fixed wiring of a structure

(2) Where run through holes in walls, structural ceilings, suspended ceilings, dropped

ceilings, or floors

(3) Where run through doorways, windows, or similar openings

(4) Where attached to building surfaces

Exception to (4): Flexible cord and cable shall be permitted

to be attached to building surfaces in accordance with the

provisions of 368.56(B)

(5) Where concealed by walls, floors, or ceilings or located above suspended or

dropped ceilings

(6) Where installed in raceways, except as otherwise permitted in this Code

(7) Where subject to physical damage

Splices may be made only in hard service cord No. 14 and larger. The splice must

maintain the insulation and outer sheath properties. Cords must be connected in a way so

as not to put tension on the terminal. Show windows must use a type insulation listed in

400.11.

Where passing through holes in covers, outlet boxes, or similar enclosures, the cord

must be protected by bushings or fittings.

Construction Specifications

The manufacturer uses the specifications in Section 400.20 through 400.24 in their

construction of flexible cords. Briefly discuss the types of identification of grounded and

grounding conductors in flexible cords.

APPLICATION:



If time will allow, correct the worksheets and discuss the results. Be sure the

students understand Article 400.



ARTICLE 400

LEVEL I

WORKSHEET

1. What would be the ampacity of a No. 18 two conductor type SO cord?

a. 6 amperes

b. 8 amperes

c. 10 amperes

d. 12 amperes

2. A splice made in junior hard-service cord shall be permitted if conductors are

spliced in accordance with 110.14(B) and the completed splice retains which of

the following except?

a. The same insulation quality.

b. The same outer sheath properties.

c. The same usage characteristics.

d. The same length.

3. SJO cord is to be marked on the cord at intervals not to exceed which of the

following?

a. 36 inches

b. 24 inches

c. 48 inches

d. 60 inches

4. Which of the following is required for appliances designed to permit ready

removal when using flexible cord?

a. A listed NM connector

b. A locking-type attachment plug.

c. An attachment plug.

d. A safety strap and lockable cover.

5. A three conductor, No. 12, 105 degree C rated STOOW cord, is being used in an

ambient temperature of 113 degrees F. These conductors shall have an ampacity of

which of the following amperes?

a. 12 amperes

b. 17.4 amperes

c. 16.9 amperes

d. 18 amperes



ARTICLE 400

LEVEL I

ANSWER KEY

1. c. 10 amps Table 400.5(A)

2. d. length 400.9

3. b. 24 inches 400.6

4. a 400.7(B)

5. b, 17.4 400.5, Table 310.15(B)(2)(a)


FIXTURE WIRES

ARTICLE 402

LEVEL I

OBJECTIVE:


requirements involving fixture wires.

MATERIALS NEEDED:

Samples of fixture wires (Table 402.3)

INTRODUCTION:

Review other articles that need to be cross referenced so as to understand permitted uses

of these conductors other than for fixture application. See Articles 410 (fixtures), Section

725.16 (class I circuits), and Section 310.15 (temperature limitations).


Sections 402.3 through 402.7 include types, ampacities, minimum sizes and

number of conductors permitted in conduit. Review these briefly.

Give handouts of Table 2 from Chapter 9 and Table 402.3 and discuss each or have

students turn to these pages in NEC during discussion.

When reviewing permitted uses in Sections 402.10 and 402.11, it is important that the

students understand required marking of Section 402.9 so that misapplications can be

avoided.

It is imperative that the student know when conductors in question are tapped to the

branch-circuit conductor of a branch circuit, Article 240.5 (B)(2) specifies

overcurrent protection for fixture wires.

APPLICATION:





FIXTURE WIRES

ARTICLE 402

LEVEL I

WORKSHEET

1. The ampacity of a #16 fixture wire is?

a. 10 amperes

b. 8 amperes

c. 6 amperes

d. 12 amperes

2. What is the minimum size of fixture wires permitted by the Code?

a. # 12 AWG

b. # 14 AWG

c. # 16 AWG

d. # 18 AWG

3. Fixture wires shall not be used as which of the following?

a. as branch circuit conductors

b. as lamp cord circuits

c. as flexible cords

d. all of the above

4. What is the maximum operating temperature of type HFF fixture wire?

a. 150º F/302º C

b. 302º F/150º C

c. 165º F/340º C

d. 340º C/165º F


FIXTURE WIRES

ARTICLE 402

LEVEL I

ANSWER KEY

1. b. 8 amperes Table 402.5

2. d. #18 402.6

3. a. 402.11

4. b. 302º F / 150º C Table 402.3


SWITCHES

ARTICLE 404

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the requirements

concerning the installation and construction specifications of switches.

MATERIALS NEEDED:

Sample of different snap switches. Sample

of a safety switch.

INTRODUCTION:

Any switch should open all ungrounded conductors of the circuit. In no case may a single-

pole switch be placed in the grounded conductor. Number of poles required for switches

to control three common types of circuits: (1) two-wire single phase or DC circuit with

one conductor grounded; (2) three-wire single phase or DC circuit with grounded neutral;

and (3) four-wire three-phase circuit with grounded neutral.

Opening only the grounded wire of a two-wire circuit would leave all devices that are

connected to the circuit alive. The voltage to the ground would equal the voltage between

the wires on the mains. In case of accidental ground on the grounded wire, the circuit

would not be controlled by the single-pole switch.

Lamps that are connected between the neutral and the two or three outer wires of the three-

wire and four-wire circuits are not balanced. If the neutral is the opened, it would cause the

voltages to become unbalanced and might burn out all lamps on the more lightly loaded

side. In any case, a switch may be arranged to open the grounded conductor if it

simultaneously opens all the other conductors of the circuit. Since three-way and four-way

switches are actually single-pole switches, they must not be used to disconnect the ground

circuit wire because this would be a violation. See 404.2.

A metal switch plate, if not grounded, may become "alive" by reason of contact of the

ungrounded circuit wire with the plate or switch box. A hazard is thus created.

Rating of Snap Switches:

For an AC General Use Switch resistive and inductive load, not including any tungsten-

filament lamps, a snap switch is merely required to have an ampere rating at least equal

to the ampere rating of the load it controls. Electrically heated appliances are common

examples of such loads.


For an AC or DC General Use Switch controlling of loads consisting of tungsten

lamps alone, and for combined tungsten-filament with any other non-inductive

load, snap switches should be "T" rated.

Inductive loads which are commonly controlled by snap switches are fluorescent

lamps, mercury-vapor lamps, and gas-tube signs and lighting. The term "snap

switch" as used here and elsewhere in the Code is the common type of flush and

surface-mounted switches. They are used for the control of lighting equipment

and small appliances and are generally of the tumbler or toggle type switch.


The provision of Article 404 shall apply to all switches, switching devices, and

circuit breakers where used as switches.

Three- and four-way switches shall be wired so that all switching is done only in

the ungrounded conductors.

Exception: Switches or circuit breakers shall not disconnect the grounded

conductor unless they disconnect all conductors of the circuit simultaneously or

are arranged so that the grounded conductor cannot be disconnected until the

ungrounded conductors of the circuit have been disconnected.

Switches and circuit breakers shall be of the externally operable type mounted in

an enclosure listed for the intended use. The enclosure shall have wire bending

space to comply with Section 312.6. If installed in a wet location, they shall be in

a weatherproof enclosure. Time switches and similar devices do not need to be

externally operable.

Single-throw knife switches shall be installed so that gravity will not tend to close

the blades. They shall be so connected so that the blades are de-energized when the

switch is open.

Double-throw knife switches mounted where the throw is vertical shall be

provided with a locking device to hold the blade in the open position.

General use and motor-circuit switches mounted in enclosures listed for the

intended use shall clearly indicate whether they are in the open, off or closed "on"

position, all except the double-throw switches.


All switches and circuit breakers used as switches shall be so

located that they may be operated from a readily accessible place.

The center of the grip of the operating handle when in its highest

position shall not be more than 6’ 7” above the floor or working

platform. There are three exceptions to this listed in 404.8.

Voltage between snap switches cannot exceed 300 volts unless

permanently installed barriers are installed between adjacent

switches.

Face plates shall be installed so as to completely cover the wall

opening and seat against the wall surface.

A handle-operated circuit breaker can be used as a switch if it has

the required number of poles.

Enclosures for switches or circuit breakers shall be grounded. Where

nonmetallic enclosures are used with metal-sheathed cables or

metallic conduits, provisions shall be made for grounding continuity.

Knife switches rated at over 1200 amperes at 250 volts or less, and at

over 1000 amperes at 251 to 1000 volts, shall be used only as

isolating switches and shall not be opened under load. To interrupt

currents above these ratings a circuit breaker or a switch of special

design listed for such use shall be used. Knife switches less than these

ratings shall be considered general-use switches.

AC general-use snap switches can be used for resistive and inductive

loads not exceeding the ampere rating of the switch at the voltage

involved on tungsten-filament lamp load not exceeding the ampere

rating of the switch at 120 volts, and motor loads not exceeding 80

percent of the ampere rating of the switch at its rated voltage.

AC-DC general-use snap switches can be used for resistive loads not

exceeding the ampere rating of the switch at the applied voltage,

inductive loads not exceeding 50 percent of the ampere rating of the

switch at the applied voltage, and tungsten-filament lamp loads not

exceeding the ampere rating of the switch at the applied voltage if "T"

rated. Switches rated in horsepower are suitable for controlling motor

loads within their rating at voltage applied.

APPLICATION:





SWITCHES

ARTICLE 404

LEVEL I

WORKSHEET

1. When used in a branch circuit, switches shall not disconnect which of the

following?

a. The ungrounded conductor.

b. The grounding conductor.

c. The grounded conductor.

d. The motor circuit.

2. Without exception, switches shall be externally operable and mounted in which of the

following?

a. A disconnecting means listed for electrical service.

b. An enclosure listed for the intended use.

c. A switch-type enclosure.

d. A cabinet or cut-out box.

3. Switches mounted outdoors shall be in which of the following type enclosure?

a. Waterproof

b. Weatherproof

c. Raintight

d. Moisture resistant

4. Time switches not of the enclosed-type, need to be mounted in which of the

following type enclosure?

a. Cabinet

b. Box

c. Equipment enclosure

d. All of the above

e.

5. Double-throw knife switches shall be permitted to be mounted so that the throw

is which of the following?

a. vertical

b. horizontal

c. both of the Above

d. neither of the above


6. Single-throw knife switches shall be connected so that when the switch is open

the blades are which of the following?

a. energized when the switch is in the open position

b. de-energized when the switch is in the open position

c. de-energized when the switch is in the closed position

d. locked when the switch is in the open position

7. Face plates for flush mounted snap switches shall be installed in which of the

following methods?

a. So as to completely cover the wall opening.

b. So as to be rigidly mounted and grounded.

c. So as to be straight and level.

d. So as to be easily changed.

8. A snap switch shall not be grouped or ganged in enclosures with other snap

switches, receptacles, or similar devices, unless they are arranged so that the

voltage between adjacent devices does not exceed which of the following?

a. 150 volts to ground.

b. 300 volts

c. 120/240 volts

d. 277/480 volts

9. A snap switch, without grounding provisions, being used for replacement

purposes only, and located within reach of earth, grade, conducting floors,

or other conducting surfaces shall be provided with a faceplate of

nonconducting, noncombustible material or:

a. shall be protected by a ground-fault circuit interrupter.

b. shall be rated at no more than 120 volts to ground.

c. shall be used only in residential applications.

d. shall be used in dry locations only.

10. Motor-circuit switches shall be permitted to be of which of the following types?

a. HACR Circuit-breaker type

b. Industrial rated type

c. Commercial rated type

d. Knife-switch type


11. Knife switches rated at over 1200 amperes at 250 volts or less, and at over 1000

amperes at 251 to 1000 volts, shall be used only as isolating switches and shall not

be opened if in which of the following conditions?

a. When under load.

b. When used as a motor-controller.

c. When used as a disconnecting means for a motor.

d. When used as a thermal overload for a motor.

12. Which of the following type switches simultaneously breaks the connection in

two conductors of a circuit?

a. A two-way switch.

b. A single-pole switch.

c. A double-pole switch

d. A four-way switch.

13. Which of the following type switches will make a closed circuit when thrown in

either of two positions?

a. A single-throw switch.

b. A double-throw switch.

c. A double-gang switch.

d. A single-gang switch.

14. What two items of information appear on all switches?

I. Current rating

II. Voltage rating

a. I only

b. II only

c. Both I and II

d. Neither I or II

15. Except as permitted in 240.8, a fused switch shall not have which of the

following?

a. Fuses in series.

b. Fuses in parallel.

c. Fuses in grounded conductors.

d. Fuses in motor-controllers.


SWITCHES

ARTICLE 404

LEVEL I

ANSWER KEY

1. c. grounded conductor 404.2(B)

2. b. an enclosure listed for the intended use 404.3(A)

3. b. weatherproof 404.4(A)


5. c. either or both of the above 404.6(B)

6. b. de-energized when in the open position 404.6(C)

7. a. completely cover the wall opening 404.9(A)

8. b. 300 volts 404.8(B)

9. a. ground fault circuit interrupter 404.9(B)

10. d. knife-switch type 404.13(D)

11. a. when under load 404.13(A)

12. c. double-pole (refer to 410.48 to clarify) 404.11; 110.3 (B)

13. b. double-throw 404.6(B)

14. c. both current rating and voltage rating 404.15

15. b. parallel. 404.17


RECEPTACLES, CORD CONNECTORS, AND

ATTACHMENT PLUGS (CAPS)

ARTICLE 406

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the requirements

concerning the rating, type, and of receptacles, cord connectors, and attachment plugs

(cord caps).

MATERIALS NEEDED:

Sample of different types of receptacles, cord connectors and attachment plugs.

INTRODUCTION:

Receptacles for portable cords shall not be rated less than 15 Amps for 125 volts or 250

volts. [406.3(B)] Those rated 20 Amps or less for aluminum wire must be marked

CO/ALR. [406.3(C)] Attachment plugs rated 15 or 20 amps must be dead-front

construction. Receptacles and plugs must not interchange with those of different

voltages. Receptacles that are non-grounding must not accept a grounded plug.

Receptacles installed in a damp or wet location must be approved for such location.

Floor receptacles must allow for cleaning without damage to the receptacle.

[406.9(D)]

Receptacles and plugs having grounding means must also have a grounding pole that

will not fit any other connection identified by: [406.10(B)]

1. Green hex-head screw or nut

2. Green pressure connector

3. Green adapter

4. An invisible hole must be marked green or have the word "Green"


Article 406 covers the rating, type, installation or receptacles, cord connectors, and

attachment plugs. Receptacles shall be listed and marked with the manufacturer’s name

or identification and voltage and ampere ratings. Receptacles installed on 15- and 20-

ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall

be installed only on circuits of the voltage class and current for which they are rated,

except as provided in Table 210.21(B)(2) and Table 210.21(B)(3). For replacements

where attachment to an equipment


grounding conductor does not exist in the receptacle enclosure, the installation

shall be permitted to be replaced with another non–grounding-type receptacle.

They may also be permitted to be replaced with a ground-fault circuit interrupter-

type of receptacle marked “No Equipment Ground.” 406.4(D)(1)(2) and (3).

Replacements also have to be GFCI rated, AFCI rated, TP rated, and WR rated

when required elsewhere in the code per 406 (D).

APPLICATION:





209

RECEPTACLES, CORD CONNECTORS, AND ATTACHMENT PLUGS

(CAPS)

ARTICLE 406

LEVEL I

WORKSHEET

1. Receptacles rated 20 amperes or less and designed for the

direct connection of aluminum conductors shall be

marked...,

a. CO/ALR

b. SWD

c. HID/SWD

d. GFCI

2. Receptacles incorporating an isolated grounding conductor

connection intended for the reduction of electrical noise

shall be identified by which of the following?

a. a white slash marking

b. a green dot marking

c. a red circle marking

d. an orange triangle marking

3. Non–grounding-type receptacles and connectors shall not

accept which of the following?

a. cord connectors of the pin type

b. grounding-type attachment plugs

c. grounded type attachment plugs

d. plugs for appliances

4. Receptacles shall not be installed in what position in countertops or similar work

surfaces?

a. in the face-up position

b. in a cabinet space

c. in an appliance garage

d. in the island sink area


210

RECEPTACLES, CORD CONNECTORS, AND

ATTACHMENT PLUGS (CAPS)

ARTICLE 406

LEVEL I

ANSWER KEY

1. a, CO/ALR 406.3(C)

2. d, an orange triangle marking 406.3(D)

3. b, grounding-type attachment plugs 406.8

4. a, in the face-up position 406.5(E)


SWITCHBOARDS, SWITCHGEAR, AND PANELBOARDS

ARTICLE 408

LEVEL I

OBJECTIVE:


construction and use of switchboards, switchgear, and panelboards.

INTRODUCTION:

When using switchboards, switchgear, and panelboards certain rules need to be applied

to make a safe installation. Such things as location of installation, clearances required to

service equipment, maximum number of overcurrent devices, and overcurrent protection

for the switchboard or panelboard. These things and more will be discussed in this

lesson. This article only applies to equipment of 1000 volts and less.


Article 408 should be used in conjunction with other articles to make the job Code

compliant. Some of these Articles are 240, 250, 312, 314, and 404. Specific

requirements of hazardous locations will be found in Articles 500.517.

Care needs to be taken when checking a switchboard to insure that barriers are in place to

isolate the service busbars and terminals from the rest of the switchboard. Only for

required interconnections can conductors travel from one vertical section to another

unless separated by horizontal barriers. Conductors need to be arranged so as not to cause

over heating.

Each switchboard, switchgear, or panelboard used as service equipment shall be

provided with main bonding jumpers sized according to Article 250.28(D). Each section

of a switchboard or switchgear, shall be bonded together.

On a high leg system, the high leg will have to be the center leg from front to back,

side to side or top to bottom. This leg shall be marked orange in color. Equipment

within the same single section or multi-section switchboard, switchgear or

panelboard as the meter on 3-phase, 4-wire delta-connected systems shall be

permitted to have the same phase configuration as the metering equipment.

Panelboards are required to have a room or dedicated space for servicing or inspection.

This space should include the space specified in Article 110.26, and will include a space

with the width and depth of the equipment from the floor to a height of 6ft. or the

structural ceiling. Nothing foreign to this equipment is to be allowed in this space. See

FPN and exceptions.


Switchboards shall maintain 3 foot clearance from the top of a combustible

ceiling unless totally enclosed or a noncombustible shield is placed on top of the

switchboard.

Panelboards shall have overcurrent protection not exceeding their rating. A panel

protected by an overcurrent device in another panelboard is considered protected

without additional protection in the subpanel. Service panels when complying

with 230.71(2-6 mains) do not need main overcurrent protection. A panel with

two mains is allowed but is limited to 42 breakers and 2 or 3 pole units count as 2

or 3 breakers respectfully. Another exception is allowed for existing residential

service panels of the split bus type.

Panelboards with 30 ampere "snap switches" cannot have overcurrent protection

above 200 amperes.

Overcurrent devices used for continuous load shall not exceed 80% of its rating

unless approved for 100% of its rating.

Where a panelboard is supplied through a transformer, the overcurrent protection

must have the protection on the secondary side (has 1 except.).

Delta breakers are not to be installed in any panelboard.

Panelboards shall be provided with an equipment grounding terminal and shall

not be tied to the neutral bar except in service equipment. Isolated equipment

grounds as provided for in Section 250.146(D) do not have to be tied to the

panelboard. (408.40)

APPLICATION:





SWITCHBOARDS AND PANELBOARDS

ARTICLE 408

LEVEL I

WORKSHEET

1. As viewed from the front of the switchboard or panelboard the phase

arrangement on 3-phase buses shall have that phase having the higher voltage to

ground on 3-phase, 4-wire, delta-connected systems marked as which of the

following?

a. Orange, C phase

b. Orange, B phase

c. Orange, A Phase

d. Brown, B phase

2. Unused openings for circuit breakers and switches shall be closed using

identified closures, or other approved means that provide protection

substantially equivalent to which of the following?

a. The thermal rating of the wire.

b. The circular mils rating of the wire.

c. The wall of the enclosure.

d. The length of the wire penetration.

3. Minimum distances between the top of a switchboard to a combustible ceiling is:

a. 0 clearance

b. 1 foot

c. 2 feet

d. 3 feet

4. Plug-in-type overcurrent protection devices or plug-in type main lug assemblies

that are backfed and used to terminate field-installed ungrounded supply

conductors

a. shall not be used in service panels.

b. may be used with engineering supervision.

c. shall be secured in place by an additional fastener.

d. may be used if rated no higher than 30 amperes.


5. Which of the following is the minimum spacing between busbars of opposite

polarity mounted on the same surface in a 1000 volt panelboard?

a. 1 1/4 inches

b. 2 inches

c. 3 inches

d. 1/2 inch

6. Maximum number of main breakers allowed on non-service panelboard is which of

the following?:

a . 2

b . 4

c . 6

d . 8

7. Where the panelboard is used with nonmetallic raceway or cable or where

separate grounding conductors are provided, which of the following shall be

provided for and properly secured inside the cabinet for the grounding

conductors?

a. A bonding jumper.

b. A grounding jumper.

c. A terminal bar.

d. A grounding electrode conductor.


SWITCHBOARDS AND PANELBOARDS

ARTICLE 408

LEVEL I

ANSWER KEY

1. b. orange, B phase 408.3(E) (1) and 110.15

2. c. the wall of the enclosure 408.7

3. d, 3 feet 408.18

4. c, 408.36 (D)

5. b. 2 inches Table 408.56

6. a, 2 408.36

7. d. terminal bar 408.40


LIGHTING SYSTEMS OPERATING AT 30

VOLTS OR LESS

ARTICLE 411

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with requirements in

regard to lighting systems operating at 30 volts or less and their associated

components.

INTRODUCTION:

This article covers lighting systems at 30 volts or less and their associated

components.


Review Scope of 411.1 and review new change to note the article now covers

lighting equipment connected to a Class 2 power source.

Review 411.3 (A-B)

Lighting systems operating at 30 volts or less each are limited to 25 amperes

maximum

Specification location requirements are found in Section 411. 5.

Secondary circuits shall not be grounded. Bare conductors shall not be installed less than

7 feet. (2.1 m) above the finished floor, unless specifically listed for a lower installation

height. 411.6 (A_D)

Lighting systems covered by Article 411 shall be supplied from a maximum 20-ampere

branch circuit. 411.7

APPLICATION:



If time allows, correct the worksheet and discuss the results.


LIGHTING FIXTURES, LAMPHOLDERS,

LAMPS, AND RECEPTACLES

ARTICLE 410

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with the specifications and

requirements for construction and installation of luminaires and lamps and lampholders.

MATERIALS NEEDED:

Samples of ceiling incandescent light, recessed light, fluorescent light and chain hung

lights.

INTRODUCTION:

When dealing with luminaires, we are covering a broad range of things, such as

incandescent, arc lamps, and electric discharge lamps. This Section also includes wiring

and construction of luminaires.


All live parts of luminaires shall not be exposed such as luminaires with open bases or

metal canopies. Cleat type lampholders must be located at least 8 feet above the floor

in order to be allowed to have exposed terminals. (410.5) Exception

Luminaires used for specific location shall be suitable for said location and marked to

indicate such approval. For example, luminaires used in a wet location must be

approved for a wet location and marked "Suitable for wet locations". Any area which

the luminaire is likely to be saturated with water or a similar liquid shall be considered

a wet location. Areas subject to moderate degrees of moisture shall be considered as a

damp location. Luminaires used with cooking hoods in non-residential occupancies

shall meet the following requirements: [410.10(C)]

1. The luminaire shall be listed for such use and the temperature limit of the

luminaires shall not be exceeded.

2. The luminaire shall be constructed so that exhaust vapors, grease, oil or

cooking

vapors are excluded from the lamp and wiring compartment. Diffusers shall be

resistant to thermal shock.

3. Parts of the luminaire exposed within the hood shall be corrosion resistant or

protected against corrosion, and the surface shall be smooth so as not to collect

deposits and to facilitate cleaning.


4. Wiring methods and materials supplying the luminaire(s) shall not be exposed within

the cooking hood..

No hanging luminaires shall be within 3 feet horizontally and 8 feet vertically of the top

rim of a bathtub or shower threshold. [410.10(D)]

410.10 (F) review this new section related to installations in or under roof decking.

Luminaires must be installed so as combustible material will not be subjected to

temperatures in excess of 90 degrees Celsius. (410.11)

When luminaires are installed over combustible material, unless each luminaire has a

switch provided, shall be unswitched and located at least 8 feet above the floor and

located so as the lamps cannot be readily removed or damaged. (410.12)

Unless chain supported show-window shall not be externally wired.

(410.14)

The types of luminaires permitted in clothes closets are restricted and the definition of

storage space safety clearly defined. Cover these requirements in depth as installation

in clothes closets are frequently encountered. (410.16(C)

Luminaires shall be made so as not to subject conductors to temperatures higher than the

rating of the conductor. Boxes that are integral parts of luminaires shall not be used as

through wiring for branch circuits unless the luminaire is identified for through wiring.

(410.21)

Unless the luminaire covers the box, a cover shall be provided to cover all

connections. (410.22)

Electric discharge luminaires supported independent of the outlet box shall be connected

to the branch circuit through metal raceway, nonmetallic raceway, Type ML cable, Type

AL cable, Type MI cable, nonmetallic sheathed cable or by flexible cord as permitted in

Section 410.24(A). (410.62)(B) 410.62(C)

When a luminaire exceeds 6 lbs. or l6 inches in dimension, it shall not be supported to

shell of lampholder. 410.30(A) Cover requirements for metal pole supporting

luminaires 410.30(B)(1)


Luminaires supported solely by an outlet box shall be installed by 314.27. Where a

suspended ceiling is used to support a luminaire, the framing members must be securely

fastened to each other and to the building structure. The luminaire shall then be securely

fastened to ceiling framing member by bolts, screws, rivets, or approved clips approved

for such use. Luminaire studs not a part of outlet boxes or approved accessories shall be

made of malleable iron. Insulating joints that are not designed to be mounted with screws

or bolts shall have an exterior metal casing insulated from both screw connections.

Raceway fittings used to support a luminaire shall be capable of supporting the weight of

the complete luminaire assembly including lamps. (410.36)(E)

Exposed metal parts shall be grounded or insulated from ground and other conducting

surfaces or inaccessible to unqualified persons. Lamp tie wires, mounting screws, clips,

and decorative bands on glass spaced at least 1 1/2 in. from lamp terminals shall not be

required to be grounded. (410.42)

Luminaires shall be considered grounded if connected to a grounding conductor

described in 250.118 and sized by Table 250.122. (410.46)

Excess wiring to a luminaire shall be avoided to prevent physical damage.

(410.48)

Cover polarization of luminaires as is required in Section 410.50.

The requirements included in Sections 410.48 through 410.52 are generally used by the

testing laboratory. Compliance is primarily accomplished by requiring listed or labeled

luminaires.

410-59 (A-C) Showcases that are portable shall be permitted to connected by flexible

cord up to six (6) different showcases. Where more than one case is hooked together

locking type connectors shall be used. These cords shall ampacity equal to the branch

circuit wiring and overcurrent device. Receptacles and plugs shall be rated at 15 or 20

Amps. Cables shall be supported to the underside of the showcase so as to:

1. Protect it from mechanical damage.

2. Assure a space of no more than 2 inches between cases nor more than l2

inches between the fixed outlet and the first case.

3. The free lead end of the last case has a female end not extending beyond

the case.

4. No other equipment shall be connected to these cases and electric

discharge lighting shall not extend beyond the case. (410.59)(D)


Where lampholders are attached to the cord, they shall be protected by a bushing. If using

a threaded nipple then it must be at least 3/8 pipe size. Bushed holes 9/32 in size where

used with plain cord and 13/32 with reinforced cord. Adjustable luminaires shall not be

required to have an attachment plug where extra-hard or hard usage cords and no long

than required for adjustment. (410.62(A)

Fluorescent-type lights can be wired with cord as long as no strain is put on the cord

and it is attached by plug. A listed luminaire or a listed feature assembly with a cord

and canopy is not required to be connected by an attachment plug. (410-62 (B)

Electric discharge lights equipped with mogul-base, screw-shell shall be permitted to be

protected by Section 240.4 if 50 Amps or less. Outlets and plugs must be rated at least

125% of the rating of the luminaire load. (410.62)(C)(2)

Luminaires shall not be used as a raceway unless listed and marked for such use

(410.64).

Conductors within 3 inches of a ballast must be rated at least 90 degrees Celsius.

(410.68)

410-82 (A_B) review

Portable luminaires shall comply with the following:

1. Metal-shelled, paperlined lampholders shall not be used.

2. Shall be equipped with handle that is insulated.

3. Must have a guard attached to handle or lampholder.

4. Metallic guards must be grounded.

5. Portable handlamps shall not be required to be grounded where supplied through an

isolating transformer with an ungrounded secondary of not over 50 volts.

Exposed live parts must have 1/2 inch clearance between exposed parts and

mounting plane. (410.46)

Lampholders having a switch must disconnect both ungrounded conductors.

(410.93)

Incandescent lamps shall have medium base up to 300 watts, mogul-base up to 1500

watts and special base for over 1500 watts. (410.103)


Luminaires shall not subject combustible material to a temperature in excess of 90

degrees Celsius unless construction is fire resistant material then the luminaire, if properly

marked, can be rated up to 150 degrees Celsius. Unless a luminaire by design offers

equivalent protection or is listed and approved for use in poured concrete, recessed

luminaires must be thermally protected and so identified. (410.115 (A-C)

Recessed lights must have 1/2 clearance to combustibles, and thermal insulation must not

be installed within 3 inches of recessed enclosure or ballast and over top so as to entrap

heat unless they are type I.C. (410.116)(B)

Tap conductors of a type suitable for the temperature encountered shall be permitted to

run from the luminaire terminal connection to an outlet box placed at least one foot from

the luminaire. Such tap conductors shall be in suitable raceways or type AC or MC cable

of at least 18 inches (450 mm) but not over 6 feet in length. [410.117(C)]

Maximum wattage of lamps in recessed lamps shall be marked in letters at least l/4

inches high where visible when relamping. Solder shall not be used in construction of

the luminaire box. (410.120) (410.121)

[410.130(E)]

(1) The ballast of a fluorescent luminaire installed indoors shall have integral thermal

protection. Replacement ballasts shall also have thermal protection.

(2) A simple reactance ballast, used in fluorescent luminaires with straight tubular lamps

shall not be required to be thermally protected.

(3) A ballast in a fluorescent exit luminaire shall not have thermal protection.

(4) A ballast in a fluorescent luminaire that is used for egress lighting energized only

during an emergency shall not have thermal protection.

[410.73(F)]

(1) Recessed high-intensity luminaires designed to be installed in wall or ceiling cavities

shall have thermal protection and be identified as thermally protected.

(2) Thermal protection shall not be required in a recessed high-intensity

luminaire whose design, construction, and thermal performance characteristics are

equivalent to a thermally protected luminaire and are identified as inherently protected.

(3) Thermal protection shall not be required in a recessed, high-intensity

discharge luminaire identified for use and installed in poured concrete.

(4) A recessed remote ballast for a high-intensity discharge luminaire shall

have thermal protection that is integral with the ballast and be identified as thermally

protected.

Open circuit voltage in excess of 300 volts shall not be used in dwellings unless such

equipment is designed so that there will be no exposed live parts when lamps are being

inserted, are in place, or are being removed. (410.135)

Luminaires on low-density combustible cellulose fiberboard shall be approved for this use


or be spaced at least 1 1/2 inches from surface. [410.136(B)]

Review 410.151 (B) and explain the new language regarding load calucaltions.Lighting

track shall only have fittings approved for lighting track installed. No general purpose

receptacles shall be connected to lighting track. Lighting track shall not be used in the

following locations: 410.151(C)

1. Where subject to physical damage

2. Damp or wet location

3. Where subject to corrosive vapors

4. Storage battery rooms

5. Hazardous location

6. Concealed

7. Through walls or partitions

8. Less than 5 feet above finished floor except where protected

9. Within the zone measured 3’ horizontally and 8 ’ vertically from the top of the

bathtub rim. Track for use in excess of 20 amps shall be considered heavy duty.

(410.153)

Single sections of Track 4 feet or less shall have 2 supports. Where in one

continuous length each 4 feet section shall have one additional support. (410.154)

Track conductors shall be a minimum of #12 or equal. (410.155)(A)

APPLICATION:





LUMINAIRES, LAMPHOLDERS, AND LAMPS

ARTICLE 410

LEVEL I

WORKSHEET

1. Hanging luminaires shall not be installed within what distance vertically of a bath tub

rim?

a. 4 feet

b. 6 feet

c. 8 feet

d. 10 feet

2. Which of the following is the proper clearance that surface mounted incandescent

luminaires mounted on the ceiling of clothes closets must have?

a. 6 inches

b. 12 inches

c. 18 inches

d. 24 inches

3. Any luminaires weighing more than which of the following shall not be supported by

the screw shell.

a. 6 pounds

b. 8 pounds

c. 10 pounds

d. 12 pounds

4. Luminaires with open or partially enclosed lamps and pendant luminaires or

lampholders of which of the following type shall not be permitted in clothes

closets?

a. Luminescent

b. Intumescent

c. Fluorescent

d. Incandescent


5. Where no equipment grounding conductor exists at the outlet, replacement

luminaires shall not be required to be connected to an equipment grounding

conductor when installed in which of the following manners?

a. With wiring rated less than 20 amperes.

b. With wiring rated more than 20 amperes.

c. When directly fastened to a grounded mounting bracket.

d. When GFCI protected.

6. In general, luminaires shall not be used as a raceway for circuit conductors unless

which of the following applies?

I. Unless they are listed for raceways.

II. Unless they are marked for use as a raceway.

a. I only

b. II only

c. Both I and II

d. Neither I or II

7. A luminaire requiring supply wire rated higher than 60°C (140°F) shall be marked

in letters not smaller than which of the following?

a. 1/2 inch high

b. 3/4 inch high

c. 5/8 inch high

d. 1/4 inch high

8. When installing a luminaire to the bottom side of metal corrugated roof decking

which of the following are true

a. The fixture shall be not less than 1” unless approved

b. The fixture shall be 1 ½ “ from the top of the deck

c. The fixture shall be not less than 1” from the lowest portion of the

deck unless approved

d. The fixture shall be not less than 1 ½” from the lowest potion of the

deck

9. Thermal insulation shall not be installed within what distance of the sides of a

recessed luminaire enclosure, wiring compartment or ballast unless it is identified

for contact with insulation, Type IC.

a. 3 inches

b. 6 inches

c. 10 inches

d. l2 inches

2014 NEC Instructor Manual

and Student Worksheets -- Level 1

225

a. 15 amperes

b. 20 amperes

c. 30 amperes

d. 40 amperes

10. Lighting track shall be considered heavy duty when in excess of?


LIGHTING FIXTURES, LAMPHOLDERS, LAMPS, AND

RECEPTACLES

ARTICLE 410

LEVEL I

ANSWER KEY

1. c, 8 410.10(D)

2. b. 12 inches 410.16(C)(1)

3. a. 6 lbs. 410..30(A)

4. d. incandescent. 410.16(B)

5. d, GFCI protected 410.44 Ex 3

6. c. Both I and II 410.64

7. d. 1/4 inch high 410.74(A)

9. d 1 1/2 “ from lowest 410. 10 (F)a. 3 inches 410.116(B)

10. b. 20 amps 410.153


LIGHTING SYSTEMS OPERATING

AT 30 VOLTS OR LESS

ARTICLE 411

LEVEL I

WORKSHEET

1. Low voltage lighting systems shall operate at a maximum voltage of?

a. 120 volts

b. 50 volts

c. 30 volts

d. 12 volts

2. Lighting systems circuits operating at 30 volts or less shall not be installed where

concealed or extended through a building wall unless

(1) installed using any of the wiring methods specified in Chapter 3

(2) installed using wiring supplied by a listed Class 2 power source

and installed in accordance with 725.130

a. 1 only

b. 2 only

c. neither 1 or 2

d. either 1 and 2

3. On secondary circuits, bare conductors shall not be installed less than which of

The following distances above the finished floor?

a. 6 1/2 ft.

b. 7 ft.

c. 7 1/2 ft.

d. 8 ft.

4. Lighting systems operating at 30 volts or less shall be supplied from a branch

circuit with a maximum ampere rating of which of the following?

a. 15

b. 20

c. 25

d. 30


LIGHTING SYSTEMS OPERATING

AT 30 VOLTS OR LESS

ARTICLE 411

LEVEL I

ANSWER KEY

1. c, 30 volts 411.3 (A)

2. d 411.5(A)

3. b. 7 ft. 411.6C

4. b. 20 411.7


APPLIANCES

ARTICLE 422

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with appliances and the

requirements for branch-circuit sizing, their installations, control, and protection.

MATERIALS NEEDED:

Samples of appliances. Handout with pictures of appliances.

INTRODUCTION:

The definition of an appliance is "utilization equipment, generally other than industrial,

normally built in standardized sizes or types which is installed or connected as a unit to

perform one or more functions such as clothes washing, air conditioning, food mixing,

deep frying, etc.".

With as much contact as we have with appliances at home, work, and play, it is very

important that they be installed and wired in a safe manner. In this lesson, we will

study the following National Electrical Code requirements:

1. The general requirements of appliances.

2. Branch-circuit requirements.

3. Installation of appliances.

4. Control and protection of appliances.

5. Marking of appliances.


Article 422 covers electrical appliances used in any occupancy with the exception of

appliances in which the current-carrying parts at high temperature are necessarily

exposed, such as toasters and grills. Appliances shall have no live parts normally

exposed.

Review new section 422.5 GFCI- protection

Where applicable, all requirements of the Code shall apply. If used in hazardous

locations, appliances shall comply with Articles 500 and 517. An appliance containing

hermetic refrigerant motor-compressors shall comply with Article 440.

The rating of an individual branch-circuit shall not be less than the marked rating of the

appliance with the following exceptions. (422.10 (A)


Motor operated appliances not having a marked rating shall be in accordance with Part

II of Article 430.

An appliance other than motor-operated that is continuously loaded shall

have a branch circuit rated not less than 125% of the marked rating or 100% if listed

Branch circuits for household cooking appliances shall be permitted to be

in accordance with Table 220.55 and sized in accordance with 210.19(A)3

422.10(B) circuits supplying 2 or more loads branch circuit supplying appliances and

other loads. shall be protected in accordance with 210.23.

If an appliance is marked with a protective device rating, the overcurrent device rating

shall not exceed this marking. [422.11(A)]

Review new requirements for Water Heaters in 422.11(F)3

Central heating equipment, other than fixed electric space heating equipment, shall be

supplied by an individual branch circuit. (422.12)

All fixed storage-type water heaters having a capacity of 120 gallons or less shall have a

branch-circuit rating no less than 125% of the name plate rating of the water heater.

(422.13)

In industrial occupancies, infrared heating appliance lampholders shall be permitted to

be operated in series on circuits of over 150 volts to ground, provided the voltage rating

of the lampholders is not less than the circuit voltage.. (422.14)

The types of cords and how they are installed on an appliance is shown in Section

422.16.

Review new sections 422-19 Space for Conductors; 422.20 Outlet Boxes to be

Covered; 422.21 Covering of Combustible Material at Outlet and 422.23 Tire

Inflation and Automotive Vacuum Machines

Make note of new GFCI requirement

Each electrically heated appliance that is located in a fixed position shall be placed

as to provide ample protection between the appliance and adjacent combustible

material.(422.17)

Wall-mounted ovens and counter-mounted cooking units complete with provision for

mounting and or making electrical connections shall be permitted to be permanently

connected or, only for ease of serving or installation, cord-and-plug connected. When a

separable connection or a plug and receptacle is used it shall be approved for the

temperature of the space. [422.16(B)(3)]


A means shall be provided to disconnect each appliance from all grounded conductors. If

supplied from more than one source, the disconnecting means shall be grouped and

identified. (422.30)

Permanently connected appliance rated at not over 300 volt amperes or 1/8 Hp may

use branch-circuit overcurrent devices as the disconnecting means. [422.31(A)]

For permanently connected appliances of greater rating, the branch-switch or circuit

breaker shall be permitted to serve as the disconnecting mean where readily accessible to

the user of the appliance. See Section 422.32 for motor drive appliance of more than 1/8

horsepower. [422.31(B)]

When unit switches are used as disconnecting means they shall meet all requirements

for disconnecting means. All switches and circuit breakers used as disconnecting means

shall meet all requirements for disconnecting means.(422.34)

Electric heaters of the cord-and-plug connected immersion type shall be so constructed

and installed that current carrying parts are effectively insulated from electrical contact

with the substance in which they are immersed. (422.44)

Each electrical heated appliance intended to be applied to combustible material such as

and iron, shall be equipped with an approved stand. These appliances in other than

dwelling type occupancies shall be provided with a signal unless it is provided with an

integral temperature-limiting device. (422.45)

Electrically heated smoothing irons shall be equipped with an identified

temperature-limiting means. (422.46)

Storage and instantaneous-type water heaters shall be equipped with a temperature

limiting means in addition to its control thermostat to disconnect all ungrounded

conductors. (422.47)

Unless identified as suitable for use with infrared heating lamps within their rated

wattage, screw-shell lampholders shall not be used with infrared lamps over 300 watts. If

300 watts or less, they shall be permitted with lampholders of medium-base unswitched

porcelain type. (422.48)

All switches and circuit breakers used as disconnecting means shall be of the

indicating type. (422.35)

The disconnecting means for a motor operated appliance of more than 1/8

horsepower shall comply with 430.109 & 431.110.. (422.32(C)

If the branch circuit supplies a single non-motor-operated appliance rated at more than

13.3 amperes, the overcurrent device shall not exceed 150% of the appliance rating. If

the appliance is rated at 13.3 amperes or less, the largest overcurrent device allowed is

20 amperes. [422.11(E)]


Review 422.51 (B) Vending Machines Other than Cord and Plug Connected

Each electric appliance shall be provided with a nameplate marking that is located so as

to be visible or easily accessible after installation. Information that is to be on the

nameplate can be found in 422.60.

APPLICATION:





APPLIANCES

ARTICLE 422

LEVEL I

WORKSHEET

1. Article 422 covers electric appliances used in which of the following

occupancies?

a. single family dwellings

b. multi-family dwellings

c. commercial and industrial

d. all occupancies

2. The installation of motor-operated appliances is governed by which of the

following?

a. Article 440

b. Article 430

c. Article 300

d. Article 250

3. When the branch circuit switch or circuit breaker is being used as the

disconnecting means for appliances rated higher than which of the following,

the provision for locking or adding a lock to this disconnecting means shall be

installed on or at the switch or circuit breaker used as the disconnecting means

and shall remain in place with or without the lock installed.

a. 1/2 horsepower, 300 volt-amperes

b. 1/8 horsepower, 300 volt-amperes

c. 1/3 horsepower, 300 volt-amperes

d. 1/4 horsepower, 300 volt-amperes

4. For branch circuits supplying appliance and other loads, the rating shall be

determined in accordance with which of the following?

a . 210.23

b . 422.12

c . 310.16

d . 310.15(B)


5. If a protective device rating is marked on an appliance, the branch-circuit

overcurrent device rating shall not exceed which of the following?

a. The protective device rating marked on the breaker.

b. The protective device rating marked on the appliance.

c. The protective device rating marked in the Code.

d. The protective device rating of the branch circuit.

6. Under which of the following conditions are cord-and-plug connected range

hoods permitted to be terminated without the use of a grounding-type

attachment plug?

a. If the receptacle is accessible.

b. If the receptacle is located to prevent damage to the cord.

c. If the receptacle is supplied by an individual branch circuit.

d. If the range hood is double-insulated.

7. Which of the following statements about cord-and-plug connected appliances in

dwelling unit kitchens is/are correct?

A. The length of cord for waste disposers shall be three to four feet long.

B. A trash compactor protected by a system of double insulation shall not

be required to be grounded.

a. A only

b. B only

c. Both A and B

d. Neither A nor B

8. Where the separable connector or plug and receptacle are not accessible, cord-

and-plug-connected appliances shall be provided with disconnecting means in

accordance with 422.31. Which of the following is acceptable for an appliance

rated at 1/8 horsepower and 300 volt-amperes?

a. The branch circuit switch.

b. The circuit breaker.

c. Both A and B.

d. Neither A or B.


9. Which of the following statements about when heated appliances are required to be

provided with a signal is not correct?

a. If in any occupancy but dwelling types.

b. If applied to combustible material

c. If not provided with an integral temperature-limiting device.

d. If it is in reach of a grounded object.

10. Cord-and-plug-connected vending machines manufactured or re-

manufactured on or after January 1, 2005, shall include a ground-fault circuit-

interrupter as an integral part of the attachment plug or be located within what

distance of the attachment plug.

a. 18 inches

b. 12 inches

c. 24 inches

d. 36 inches

11. A branch circuit supplying a fixed storage-type water heater having a capacity of

120 gallons or less shall have a rating not less than which of the following?

a. 100 percent of the marked rating of the appliance.

b. 125 percent of the marked rating of the appliance.

c. 80 percent of the marked rating of the appliance.

d. 250 percent of the marked rating of the appliance.

12. Screw-shell lampholders shall not be used with infrared lamps rated over 300

watts, unless the lampholders are identified as being suitable for use with which of

the following?

a. Infrared heating lamps rated under 300 watts.

b. Infrared heating lamps rated over 300 watts.

c. Infrared heating lamps rated for non-commercial use.

d. Infrared heating lamps rated for industrial use.

13. Permanently connected air-conditioning equipment shall be permitted to be

connected to the same branch circuit as which of the following?

a. Fixed electric space-heating equipment.

b. Central heating equipment.

c. Unitary heating systems.

d. Proprietary heating systems.


14. If a switch or circuit breaker serves as the disconnecting means for a

permanently connected motor-driven appliance of more than 1⁄8 hp, it shall

be located at which of the following?

a. At the switch serving the motor using a lockout device.

b. At the motor-controller panel in an adjacent area.

c. At the motor location enclosure within 6 feet.

d. Within sight of of the appliance according to 110.25.

15. A unit switch with a marked-off position that is part of an appliance shall be

permitted as the disconnecting means if it disconnects which of the following?

a. All of the conductors.

b. All of the ungrounded conductors.

c. All of the grounded conductors.

d. All of the conductors including the grounding conductor.

16. If a protective device rating is marked on an appliance, the branch-circuit

overcurrent device rating shall not exceed which of the following?

a. The protective device rating marked on the appliance.

b. The feeder circuit rating for the branch.

c. The protective device rating marked on the circuit breaker.

d. The full load amperes of the circuit plus 25 percent.

17. Marking shall be located so as to be which of the following?

I. Visible

II. Easily accessible after installation.

a. I only

b. II only

c. Either I or II

d. Neither I or II


APPLIANCES

ARTICLE 422

LEVEL I

ANSWER KEY

1. d. all occupancies 422.1

2. b. Article 430 422.3

3. b. 1/8 horsepower, 300 VA 422.31(B))

4. a. 210-23 422.11

5. b. rating marked on the appliance 422.11(A)

6. d. if the range hood is double-insulated 422.16(B)(4) Exception

7. b, 2 only 422.16(B) Exception

8. a. ample, appliance, adjacent 422.31 (A)

9. d, If it is not in reach of a grounded object 422.42

10. b. 12 inches 422.51 (A)

11. b. 125 percent of the marked nameplate rating 422.13

12. b. rated over 300 watts 422.48(B)

13. b. Central heating equipment 422.12

14. d. within sight 422.32 (C) 2

15. b. ungrounded 422.34

16. a. 422.11(A)

17. c. visible or easily accessible 422.60(B)


FIXED ELECTRIC SPACE HEATING EQUIPMENT

ARTICLE 424

LEVEL I

OBJECTIVE:

After completing this lesson, each student should be familiar with enforcement of code

requirements for fixed electric space heating equipment.

Article 424 includes requirements for several different types of heating systems some

of which will only be encountered occasionally such as heating cable, unit heaters,

boilers, central systems, etc. This Article does not apply to process heating or room air

conditioners.


Branch Circuit Requirements

Branch circuits supplying more than one outlet for fixed electric heaters (baseboard

heaters) shall be rated 15, 20, 25 or 30 amperes. Fixed infrared equipment located in

other than residential occupancies can be supplied from branch circuits rated not over

50 amperes. [424.3(A)] Branch circuits supplying only one piece of equipment must be

rated 125% of the total load including motors and resistance heaters, except for relays

and contactors which are approved for continuous operation at 100% ampacity

[424.3(B)]. Heat pump compressors are covered under Article 440.34 and 35.

Installation

If heating equipment requires more than 60 degrees Celsius insulation on supply wiring,

it must be clearly marked and the marking must be visible after installation. (424.11)

Locations

Units subject to physical damage shall be protected in an approved manner. Units in wet

or damp areas shall be approved for such location and installed so liquid cannot enter.

(424.12)

Spacing from Combustible Material

Equipment shall be installed to provide manufacture’s requirements for clearance to

combustible materials. (424.13)

Control and Protection

A disconnecting means must be provided to disconnect all ungrounded

conductors where supplied from more than one source, feeder, or branch circuit,

disconnects shall be grouped. (424.19)


A disconnecting means for units equipped with supplementary overcurrent

devices shall be within sight from and on the supply side of supplementary

overcurrent protection, and comply with numbers 1 or 2 below.

1. For motors not over 1/8 horsepower, a disconnecting means shall be

permitted to serve both the motor controller and heater if located within

sight of both or the disconnecting means must be lockable in accordance

with 110.25. Where unit switches meet the requirements of 424.19(C)

they may be used as the required disconnecting means.

2. Units containing motors rated over 1/8 horsepower, disconnect described

in number 1 above may be used, if within sight of the motor controller and

heater.

Disconnecting means not within sight from the heater requires either a separate

disconnect be installed or a disconnect capable of being locked open or unit

switches complying with 424.19(C)

A branch circuit switch or circuit breaker may serve as a disconnecting means for

units without supplementary overcurrent protection containing motors not more

than 1/8 horsepower where readily accessible for servicing. Similar units more

than 1/8 horsepower will require a disconnect within sight of motor controller.

Unit switches may be used as disconnecting means where provided with a marked

"off" position and when meeting requirements of 424.19(C) for the type of

occupancy involved.

Thermostatically controlled switching devices may be used as both a controller

and a disconnecting means under ALL the following conditions. (424.20)

Example: thermostats for basement heat

1. Marked "off" position

2. Must open all ungrounded conductors when in "off" position (manually)

3. Must not be capable of being automatically energized when in the manual

"off" position.

4. Must be located as per Section 424.19.

Switches must be of the type indicating the "on" and "off" positions.

Overcurrent Protection

Space heating equipment supplied by branch circuits in Article 210 shall be

permitted where not supplying motor operated equipment as in Articles 430 and

440. [424.22(A)]


Resistance-type heating elements may not be protected at more than 60 amperes.

Where rated more than 48 amperes, it shall be subdivided not to exceed 48

amperes within each subdivided load. [424.22(B)]

Overcurrent protective devices for subdivided loads shall be factory installed or

factory provided, accessible and suitable for branch circuit protection. (see

Article 240.10). [424.22(C)]

Conductors supplying supplementary overcurrent protective devices shall be

considered branch circuit conductors. [424.22(D)]

Field installed conductors between supplementary protective devices and heater

shall be sized not less than 125% of load. Overcurrent protective devices shall

comply with Article 240.3. [424.22(E)].

Marking of Heating Equipment

Each unit must have manufacturer's nameplate installed and visible after

installation. [424.28(A & B)]

Space Heating Cables

Area heating cables shall not extend beyond the room in which they originate.

They shall not be installed in closets, over walls or over cabinets. [424.38]

Heating cables must be at least 8 inches from the edge of outlet boxes and

junction boxes, and at least 2 inches from recessed fixtures. [424.39]

Adjacent runs of cable not less than 1 1/2 inch on center and secured at intervals

not exceeding 16 inches. [424.41(B)]

Splices in the cable should be made only where necessary and in no case to alter

length of cable. Cables shall cross joists only at ends of room. [424.41(D)]

[424.41(J)]

Heating cables shall not exceed 16 1/2 watts per linear foot in concrete or

masonry floors.

[424.44(A)]

All cable installations must be inspected before being covered. Review typical

installation procedures. [424.45]

Duct Heaters

All duct heaters must first be identified as suitable for installation. [424.58]

If duct heater is located within 4 feet of a heat pump or air conditioner it must be

identified as suitable for such installation. [424.61]


The fan circuit must be interlocked to insure fan is running when heater

is on. [424.63]

Each heater must be provided with limit devices. [424.64]

A disconnecting means must be at or within sight from the controller.

[424.65] Installation must meet manufacturer's instructions. [424.66]

Electrode-type Boilers

Branch circuit conductors and protective devices shall be calculated at

125% of total load except for contactors, relay, or other devices approved

for continuous operation at 100% of rating. [424.82]

Over temperature and over pressure limiting controls are required and

must meet the same requirements as for resistance-type boilers. [424.83]

and [424.84]

All boilers must be marked with manufacturer's name, rating, and

electrical supply required. In addition a warning: "ALL POWER

SUPPLIES SHALL BE DISCONNECTED BEFORE SERVICING

INCLUDING SERVICING THE PRESSURE VESSEL." must appear.

[424.86]

Electric Radiant Heating Panels and Heating Panel Sets

This section of Article 424 applies to wall heaters, baseboard heaters and

other heating units which may be exposed or concealed when installation

is complete. Heating panels and heating panel sets must be installed to

meet manufacturer's installation instructions, and the conditions of

Section 424.93(A)(2):

1. Must not be installed subject to physical damage

2. Must not run through or above walls, partitions, or other

structures that extend to ceilings.

3. Must not run through or in thermal insulation.

Excess non-heating leads of heating panels and heating panel sets may be

cut to desired length. [424.97]

Heating panels or panel sets installed in concrete or poured masonry must

meet the requirements of Section 424.98. (Review requirement).

Heating panels installed under floor covering must be installed in

accordance with instructions and identified for such use and provided with

fault protection in accordance with Section 424.99. It is important for the


inspector to have access to installation instructions for the specific panel

installed. Inspection must be made prior to applying floor covering. Heating

panels installed under floor covering shall not exceed 15 watts per square

foot. [424.99]

APPLICATION:






ARTICLE 424

LEVEL I

WORKSHEET

1. Branch circuits supplying two or more outlets for fixed electric heat shall be rated


a. For fixed electric heating at 50 or more amperes.

b. 15, 20, 25 or 30 amperes.

c. 40 or 50 amperes.

d. Rated for not more than 80% of the circuit ampacity.

2. Branch circuit conductors supplying fixed electric space heating equipment shall be

considered which of the following?

a. Nonlinear loads.

b. Appliance circuits.

c. Nonlighting loads.

d. Continuous loads.

3. In heating equipment with supplementary overcurrent protection and a motor not

over 1/8 horsepower, the supplementary overcurrent protection shall be

permitted to serve as the required disconnecting means for both the motor

controller(s) and heater under which of the following conditions?

(I) The disconnecting means provided is also within sight from the

motor controller(s) and the heater.

(II) The disconnecting means provided is capable of being locked in

the open position.

a. I only

b. II only

c. Both I and II

d. Neither I or II


4. Readily accessible thermostatically controlled switching devices may be used

as both the controller and disconnecting means under which of the following

conditions?

a. Provided with a marked “off” position

b. Directly open all ungrounded conductors when manually

placed in the “off” position

c. Designed so that the circuit cannot be energized automatically

after the device has been manually placed in the “off” position

d. All of the above

5. Heating equipment requiring supply conductors shall be clearly marked when

rated more than which of the following?

a. 75º C

b. 60º C

c. 75º F

d. 60º F

6. Resistance-type heating elements in electric space heating equipment rated at 48

amperes, shall have these elements protected at not more than which of the

following ampacities?

a. 50 amperes

b. 70 amperes

c. 100 amperes

d. 60 amperes

7. All heating elements that are replaceable in the field and are part of an electric heater

shall have the element ratings legibly marked with which of the following?

a. Volts and watts.

b. Volts and amperes.

c. Neither of a or b

d. Either of a or b

8. Which of the following would be the minimum wire size in THW for 5 KW

resistance heater with a 3 amperes fan motor rated 240V/1ø.

a . # 8 b . # 10

c . # 12

d . # 1/0


9. Which of the following circumstances will allow an embedded electric space

heating cable to be spliced?

I. only where necessary to lengthen the cable

II. only by an approved means

a. I only

b. II only

c. Both I and II

d. Neither I nor II

10. How close can a duct heater be to a heat-pump air conditioner without having to be

identified for air conditioner use?

a. 4 feet

b. 6 feet

c. Within sight

d. 5 feet

11. Disconnecting means for duct heaters must be located in accordance with which of

the following?

I. be either readily accessible with the disconnecting means installed

at or within sight from the controller

II. or as permitted by 424.19(A).

a. I only

b. II only

c. Both I and II

d. Either I or II

12. A non-ASME boiler employing resistance type heating elements must be

subdivided when the elements are rated more than which of the following

amperes?

a. 50 amperes

b. 48 amperes

c. 30 amperes

d. 60 amperes


13. When cables are installed in heated floors of bathrooms and in hydromassage

bathtub locations which of the flowing shall be installed for protection for

personnel in these locations?

a. Grounding and Bonding grids.

b. Groundfault circuit-interrupter.

c. Ground bars in all panels.

d. Intrinsically Safe systems.

14. A complete assembly provided with a junction box or a length of flexible conduit

for connection to a branch circuit is describing which of the following?

a. Heating Panel Set.

b. Heating Panel.

c. Ceiling Heat Grid.

d. Floor Heating Element.

15. Heating panels or panel sets installed under floor covering shall not exceed which of

the following wattages per square foot of heated area?

a. 20 watts per square foot.

b. 18 watts per square foot.

c. 12 watts per square foot.

d. 15 watts per square foot.



ARTICLE 424

LEVEL I

ANSWER KEY

1. b. 15, 20, 25 or 30 amperes 424.3(A)

2. d. 125% 424.3(B)

3. c. Both I and II 424.19(A)(1)

4. d. All of the above 424.20(A)

5. b. 60 oC 424.11

6. d. 60 amperes 424.22(B)

7. d. either of a or b 424.29

8. b. # 10 THW copper wire 424.3(B)

9. b. Only by an approved means 424.40

10. a. 4 feet 424.61

11. b. II only 424.65

12. d. 60 amperes 424.72(B)

13. b. Ground Fault Circuit Interrupter 424.44(G)

14. b. A heating panel 424.91

15.

16. d. 15 Watts per square foot 424.99(B)


MOTORS, MOTOR CIRCUITS, AND CONTROLLERS

ARTICLE 430

LEVEL I

OBJECTIVES:

After completing this lesson, each student should be familiar with:

1. the general requirements of motors, motor circuits, and controllers.

2. specific sizes of motor controllers.

3. overload devices intended to protect motors, motor-controllers and

branch-circuit conductors.

4. specific devices used to protect motor branch-circuit conductors, motor

controllers, and motors against overcurrent due to short circuits or grounds.

5. specific protective devices for feeder conductors supplying motors against

overcurrent due to short circuits and grounds.

6. modifications of the general requirements of motor control circuits.

7. suitable controllers for all motors, and means of disconnecting motors and

controllers from the circuit.

8. how live parts should be protected in an adequate manner relative to the

hazard involved.

MATERIALS NEEDED:

National Electric Code

Samples of motors, motor circuits and controllers.

Handouts and/or pictures showing the above.

INTRODUCTION:

Article 430, dealing with motors, is somewhat unique from other articles because electric

motors come in so many different kinds and sizes. Also, motors are generally rated by

size and voltage, and general principles that apply to motors may hold true over a wide

array of motor sizes. Motor circuits are quite different from other circuits, in that, they

have different overcurrent protection for starting and have different fuse systems. As far

as motor controllers are concerned, there are many ways to control motors. One way is by

means of automatic controllers, which tend to complicate matters somewhat. Hence, a

working knowledge of motors and the like would be very helpful in understanding this

article.

Article 430 encompasses guidelines for motors, motor circuits and controllers for all

levels of inspection. Since a Level I inspector will only see certain areas governed by

this Article, cover only those sections that are typical of what a Level I inspector would

most likely experience on the job. This lesson plan will


only cover those appropriate areas. The remaining sections of this Article should

be picked up in Levels II and III.

There are many problems related to motors which require some calculations. It is

very important that one become familiar with tables 430.247 through

430.251(A)because they will be used and referred to extensively in solving

problems. Explain how to read these tables and discuss each.

Knowledge and understanding of various terms and definitions would be

extremely helpful when studying Article 430. In order to review and provide a

background for studying motors, etc., a list of definitions is included as a handout

to be distributed to the students. See handout entitled “Key Terms.”

Given the fact that this Article is rather lengthy, the instructor may want to break

down the lesson and teach only a couple of objectives at a time. It would also be

advisable to teach Article 440 along with or after Article 430.


In order to present the class with a general overview or outline of this Article, the

instructor may want to show a transparency of Figure 430.1 and explain the

relationship of the Article parts.

Part I covers provisions for motors, circuits, and controllers that are not covered

in other parts of this Article. For example, air conditioning and refrigerator

equipment are covered in Article 440. (430.1)

Some important definitions are given in this section (430.2)

Motors and controllers shall also comply with the provisions of other articles in

the Code. See the list in Section 430.5 .

All equipment covered by this Article shall be supplied by conductors selected

from allowable ampacity tables in accordance with 310.15(B) or calculated

(under engineering supervision) in accordance with 310.15(C). For general

motor applications, required ampacity and motor ratings shall be determined

as follows:

If the current rating of a motor is used to determine the ampacity

of conductors or ampere ratings of switches, branch-circuit short-

circuit and ground-fault protection, etc., then values in Tables

430.247 through 430.250 shall be consulted instead of the actual

current rating on the motor nameplate.

Separate motor overload protection shall be based on the motor

nameplate current rating.

If the motor is not marked by horsepower, but by amperes, the

horsepower rating shall be assumed to be that corresponding to


the value given in Tables 430.247 through 430.250; however, they may

need to be interpolated.

Three exceptions occur which are noted in Section 430.6(A)(1).

Motors shall be marked as indicated in Section 430.7. A discussion of markings and an

example nameplate would be helpful.

A handout of a photocopied nameplate may be helpful. [430.7(A)]

For locked rotors, code letters shall be used to mark them as illustrated in Table

430.7(B).

Controllers shall be marked with the marker’s name or identification, voltage, current or

horsepower rating, short-circuit current rating and other data necessary to properly

indicate suitable motors. If the controller includes overload protection suitable for group

motor application it shall be marked with the motor overload protection and maximum

branch-circuit short-circuit and ground-fault protection for such applications. If

combination controllers have adjustable instantaneous trip circuit breakers they shall be

marked to indicate ampere settings of the adjustable trip element. (430.8)

If the necessary data is on the nameplate then it is not required to mark individual

controllers when they are an integral part of a motor as a motor generator set. If the

controller is an integral part of equipment approved as a unit, then the markings shall be

on the equipment nameplate. (430.8)

Terminal torque requirements for control circuit devices with screw type pressure

terminals used with less than or equal to No. 14 AWG copper conductors shall be torqued

to a minimum of 7 inch-pounds unless identified for a different torque value. [430.9I,

Tables 430.12(B), 430.12(C)(1), and 430.12(C)(2)]

Motors shall be located in a manner that will permit adequate ventilation and access for

maintenance. Open motors having commutator or collector rings shall be protected so

sparks will not reach nearby combustible materials. This does not

limit the location of these motors on wooden floors or supports. (430.14)

In order to determine the largest motor, select the motor with the highest rated full-load

current, which shall be the equivalent value corresponding to the motor

horsepower rating in Tables 430-247 through 430-250. (430.17)

Branch-circuit conductors that supply a single motor shall have an ampacity not less than

125% of the motor full-load current rating. If a multi-speed motor is used, then the

branch-circuit conductors on the line side of the controller shall be based on the highest of

the full-load current ratings shown on the motor nameplate. The branch-circuit conductors

between the controller and the motor shall be based on the particular speed at which that


circuit is energized. Exceptions apply to motors used for a short time and for d-c motors

operating from a rectified single phase power supply. [430.22(A)]

When conductors supply several motors, the ampacity shall be equal to the sum of the

full-load current rating of all of the motors plus 25% of the highest rated motor in the

group. (430.24)

If one or more of the motors is short-time or periodic etc., compute the ampacity of the

conductors as follows:

1. Use Table 430.22(E) and find the needed ampere rating for each other than

continuous duty motor.

Show Table 430-22(E) and review how to interpret.

2. Find the needed ampere rating for each continuous duty motor based on

100% motor full-load current rating.

10. Take the largest single motor ampere rating from part (1) or (2) and

multiply by 1.25. Then, add all other motor ampere rating from (1) and

(2) and select the conductor ampacity for the total ampere rating.

The conductor size shall be determined from the larger motor or a group of motors

that is/are operated at a given time, if the circuitry prevents the starting and running

of a second motor or group of motors. (430.24)

If you run into conductors that supply motor loads and a lighting or appliance load, then

the ampacity shall be sufficient for the particular load and computed in accordance with

the appropriate Article as follows: (430.25)

Lighting or appliance load Article 220

Motor loads Section 430.24

Single motor load Section 430.22

Motor-operated fixed electric

space heating equipment Section 424.3(B)

Multi-motor and combination

load equipment Section 430.7(D)

Feeder tap conductors have several guidelines noted below: (430.28)

Ampacity not less than that required in part II. Terminate in a

branch-circuit protective device.

Shall meet one of the following:


1. Be enclosed by a controller or raceway and not more than 10 feet in

length, and for field installation, be protected by an overcurrent protective

device on the side of the tap conductor, the rating or setting of which shall

not exceed 1000 percent of the tap conductor ampacity.

2. Ampacity at least 1/3 that of the feeder conductors, be protected from

physical damage, not more than 25 feet in length.

3. Have same ampacity as the feeder conductors.

There is an exception to feeder taps over 25 feet long noted in 430.28. Review

conditions of the exceptions.

Those exceptions may apply as feeder taps. (240.21)

11. Motor and Branch-Circuit Overload Protection. There

are several ways to protect against overload for a continuous duty motor rated greater

than 1 horsepower. [430.32I] Asterisk percent values allow for incremental increase

in overload rating where the initial device selected in accordance with 430.32 is

insufficient to start the motor or to carry the load.

For example: The use of a separate overload device that is

responsive to motor current and will trip at no more

than the following percent of the motor nameplate

full-load current rating.

Motors with a marked service

factor not less than 1.15 125% *140%

Motors with a marked temperature

rise not over 40 degrees Celsius. 125% *140%

All other motors 115% *130%

Thermally protected motors shall have ultimate trip currents of the following

percentages of motor full-load current as stated in Tables 430.248 through 430.150.

Motor Full-Load Current Percentage

Not exceeding 9 amperes 170

9.1 to and including 20 amperes 156

Greater than 20 amperes 140

Motors greater than 1500 horsepower shall have a protective device that has

temperature detectors that cause current to the motor to be interrupted when the


motor attains a temperature rise greater than what is marked on the nameplate in

an ambient of 40 degrees Celsius. [430.32(A)(4)]

Other specifications in this Section apply for one horsepower or less motors that start

automatically and non-automatically. [430.32(B)]

If the overload relay selected in Section 430.32(A) (1) is not sufficient to start and carry

the load of the motor, then the next higher size overload relay shall be permitted to be

used if the trip current of the overload relay does not exceed the following percentages of

the motor full-load current rating. See 430.32(A)(1) figure. Show transparency Table

430.32. (Section 430.32(C))

See 430.36 concerning fuse locations.

If devices other than fuses are used as motor overload devices see Table 430.37. Show

transparency of Table 430.37 and discuss.

Overload devices other than fuses, thermal cutouts, or thermal protectors shall

simultaneously open a sufficient number of ungrounded conductors to interrupt current

flow to the motor. (Section 430.38)

For more information on thermal cutouts and overload relays, see 430.40 and note

exceptions.

The overload protection for motors used on general purpose branch-circuits shall be

specified in 430.42 as permitted in Article 210 concerning branch-circuits. Areas

specifically addressed include: less than 1 horsepower motors, greater than 1 horsepower

motors, cord and plug-connected, and time delay.

(430.42)

12. Motor Branch-Circuit Short-Circuit and Ground-Fault

Protection

The motor branch-circuit short-circuit and ground-fault protective device shall be capable

of carrying the starting current of the motor; however, the protective device shall not have

a setting exceeding the calculated value given in Table 430.52. Exception No. 1 and 2

may be considered as the general rule because they occur more often than not. (430.52)

Several motors or loads on one branch-circuit shall be permitted to be connected to the

same branch-circuit under certain conditions.

If the motors do not exceed 1 horsepower in rating they shall be permitted on a nominal

120 volt branch-circuit protected at not over 20 amperes or as a branch circuit of 1000

volts, nominal, or less, protected at not over 15 amperes, if certain conditions are meet:

1. The full-load rating of each motor does not exceed 6 amperes.


2. The rating of the branch-circuit short-circuit and ground-fault

protective device marked on any of the controllers is not exceeded.

3. Individual overload protection conforms to Section 430.32. (430.53)

Branch-circuit protective devices shall comply with the provisions of Section 240.15.

(430.56)

Fuseholders shall not be of a smaller size than required to accommodate the fuses

specified in Table 430.52. Show transparency of this Table.

Smaller fuseholders than specified in the Table shall be permitted if the fuses have

time delay appropriate for the starting characteristics of the motor used. (430.57)

V. Motor Feeder Short Circuit and Ground Fault Protection

Any feeder supplying a specific motor load using conductors based on Section 430.24

shall have a protective device with a rating not greater than the largest rating of the

branch-circuit short-circuit and ground-fault protective device for any motor of the

group plus the sum of the full-load currents of the other motors of the group. Table 430.

52 shall be used to determine maximum settings for branch-circuit short-circuit and

ground-fault protective devices.

Section 440.22(A) shall be reviewed for hermetic refrigerant motor-compressors.

When feeder conductors have an ampacity greater than required by 430.24, the rating

of the feeder protective devices shall be permitted to be based on the ampacity of the

feeder conductors. [430.62(A)]

Where a feeder supplies a motor load and a lighting and or appliance, the feeder

protective device shall be permitted to have a sufficient rating to carry the lighting or

appliance load as outlined in Article 210 and 220, plus for a single motor, the rating

outlined in Section 430.52 and for two or more motors, the rating permitted by Section

430.62. (430.63)

VI. Motor Control Circuits

Motor Control Circuit: The circuit of a control apparatus or system that carries the

electrical signals directing the performance of the controller, but does not carry the

main power current. (430.71)

If a motor control circuit is tapped from the load side of a motor branch-circuit short-

circuit ground-fault protective device(s) and its function is to control the motor(s)

connected to that branch-circuit, then it shall be protected against overcurrent in


accordance with Section 430.72. This tapped control circuit is not considered to be a

branch-circuit and should be permitted to be protected by a supplementary or branch-

circuit overcurrent protective device. (430.72)

Show transparency of Table 430.72(B) and explain that overcurrent protection for

conductors shall not exceed the values specified in Column A of the Table.

Review the exceptions 1-4 to this rule. (430.72)

Where damage to a motor control circuit would create a hazard, then all conductors of the

control circuit that are outside the control device shall be installed in a raceway or

protected from physical damage in other ways. (430.73) If one side of the motor control

circuit is grounded, then the motor control circuit shall be arranged so that an accidental

ground in the remote-control device will (1) not start the motor and (2) not bypass

manually operated shutdown devices or automatic safety shutdown devices. (430.74)

When the disconnecting means is in the open position, motor control circuits shall be

disconnected from all sources of supply. [430.75(A)]

The disconnecting means may consist of two or more separate devices; one that

disconnects the motor and controller from the power source and the other(s), the motor

control circuit(s) from its power supply. [430.75(A)]

When separate devices are used, they should be located immediately adjacent to one

another. Note the two exceptions to this rule. (430.75(A))

VII. Motor Controllers

In respect to this Article, a controller is any switch or device normally used to start

and stop a motor by making and breaking the motor circuit locked-rotor current.

[430.82A)]

A branch-circuit protective device shall be permitted to serve as the controller for a

stationary motor rated at less than or equal to 1/8 horsepower which is normally left

running such as a clock motor. Also, the motor must be constructed so that it cannot be

damaged by overload or failure to start. [430.81(A)

The controller may be an attachment plug and receptacle for a portable motor

rated at less than or equal to 1/3 horsepower. [430.81(B)]

The horsepower rating of the controller shall not be lower than the horsepower rating

of the motor. Pay particular attention to 430.83(A)(1) and (2).

The controller shall not be required to open all conductors to the motor, unless the

controller serves also as a disconnecting means, then it shall open all ungrounded


conductors to the motor. (430.84)

If a controller is so designed that the pole in the grounded conductors cannot be opened

without simultaneously opening all conductors of the circuit, then one pole of the

controller shall be permitted to be placed in a permanently grounded

conductor. (430.85)

Each motor shall be provided with an individual controller; however, there is an

exception. See 430.87.

A combination fuseholder and switch may be used as a motor controller if the rating of

the fuseholder will accommodate the size of the fuse recommended in Part III of this

Article for motor overload protection, unless the fuse having time delay appropriate for

the starting characteristics of the motor used, then smaller size fuseholders may be used.

(430.90)

VIII. Motor Control Centers

All requirements for motor control centers are now grouped in Part VIII. These

requirements cover design and construction of these centers except for 430.94 on

overcurrent protection.

IX. Disconnecting Means

A disconnecting means shall be located “in sight from” the controller location: The Code

specifies that one equipment shall be in “sight from” another equipment, one of the

equipment specified is to be visible and not more than 50 feet distant from the other.

Note the exceptions to this rule. [430.102(A)]

A disconnecting means shall be located “in sight from” the motor location and the driven

machinery location, except where the disconnecting means provided in accordance with

430.102(A) is capable of being locked in the open position. [430.102(B)]

The disconnecting means for both motor and controller shall be permitted in the same

enclosure with the controller. Also, it shall disconnect the motor and controller from all

ungrounded supply conductors and be designed so that no pole can be operated

independently. (430.103)

The disconnecting means shall indicate clearly whether it is in the open (off) or

closed(on) position. (430.104)

See 430.105 concerning grounded conductors. For information concerning the service

switches as a disconnecting means, see 430. One of the disconnecting means shall be

“readily accessible.”


Readily accessible: Capable of being reached quickly for operation, renewal, or

inspections, without requiring those to whom readily access is a requisite to climb over or

remove obstacles or to resort to portable ladders, chairs, etc. (Article 110, 430.107)

Generally speaking, the type of disconnecting means shall be a motor-circuit switch

rated in horsepower, a circuit breaker, or a molded case switch (nonautomatic

circuit interrupter

The ampere rating of the disconnecting means for motor circuits rated 1000

volts, nominal, or less, shall be at least 115% of the full-load current rating of the motor.

[430.110(A)]

See 430.110IC] for the ampere rating and interrupting capacity for combination

loads.

Certain types of switch and breakers may be used as both the controller and

disconnecting means. See 430.111 for details.

Each motor shall be provided with an individual disconnecting means, but a single

disconnecting means shall be permitted to serve a group of motors under any one of the

following conditions. (430.112)

Where a group of motors:

a. drive several different parts of a single machine.

b. is under the protection of one set of branch-circuit protective devices.

[See 430.53(A)].

c. is in a single room within sight from the location of the disconnecting means.

Motors receiving electrical energy from more than one source shall have disconnecting

means from each source located immediately adjacent to the equipment served, unless

the disconnecting means is capable of being locked in the open position. Also, a separate

disconnecting means shall not be required for a Class 2 remote-control circuit

conforming with Article 725, rated not over 30 volts, and is isolated and ungrounded.

Explain how motors may be fed from more than one source. (430.113)

K. Protection of Live Parts

Basically, all live parts shall be protected in a manner judged adequate to the hazard

involved.

Exposed live parts of motors and controllers operating at 50 volts or more between

terminals shall be guarded against accidental contact by enclosure or various other

ways noted below: (430.232)

1. By installation in a room or enclosure that is accessible only to qualified

persons.


2. By installation on a suitable balcony, gallery, or platform, so elevated and

arranged as to exclude unqualified persons.

3. By elevation 8 feet or more above the floor.

See 430.232 for the exception to the rule.

See 430.233 for guidelines on guards for attendants.

It may be helpful to go over sample problems with the class to illustrate the

procedures for solving typical motor problems.

The following example may not be a typical problem for a Level I inspector;

however, it requires that one know how to look up data in the tables and apply it

to solve the problems. Also, this particular example involves many of the

essential calculations required for other problems. Generally, if the student can

work out the correct answers to this problem he/she should not have much

difficulty doing other types of motor problems.

See Sample Problem.

APPLICATION:





Sample Problem

Using various sections and tables from Article 430, determine the following for one 25

horsepower squirrel-cage induction motor and two 30 horsepower wound- rotor induction

motors on a 460-volt, 3 phase, 60 Hertz supply. Assume dual-element fusing for short

circuit protection.

25 Hp 30 Hp 30 Hp

Squirrel cage Wound-rotor

Induction motor Induction motors Full volt starting 40oC rise

Service factor 1.15

Code letter F

25 Hp 30 Hp 30 Hp

Amperes

1. Full-load Current 34 40 40

(Table 430.250)

2. Conductor Size

a. Each Motor (125% FLA) 43 50 50

1.25) = 124 (430.22) b. All Motors 34 + 40 + (40 times

(430.24)

3. Motor Overload Protection 43 50 50

56

432(A)(1)]

*If not sufficient to start or carry load. 48 56

[430.32(C)]

4. Branch-circuit Short-circuit

Ground-fault Protection 60 70

70 (Table 430.52) exception 1 *If not sufficient for starting may use fuses rated: 70 90 90

[430.52 Exceptions (2)(B)]

5. Feeder Protection 70 + 34 + 40 = 144

[430.62(A)] (Use 125 standard fuse)


MOTORS, CIRCUITS, AND CONTROLLERS

ARTICLE 430

LEVEL I

WORKSHEET

1. The full-load rating of a motor found on the nameplate is 30.4 amperes and that found

in Table 430.250 is 31.8 amperes. Which value is required to be used when determining

the minimum size branch-circuit conductor permitted?

a. The nameplate rating of the motor.

b. The ampacity found in Table 430.250

c. The ampacity found in 430.52.

d. The ampacity multiplied by the difference in amperes calculated.

2. The circuit of a control apparatus or system that carries the electric signals directing

the performance of the controller but does not carry the main power current is known as


a. The Control Circuit

b. The Motor Controller.

c. The Motor Control Circuit.

d. The Control Center.

3. Motors shall be located so that adequate ventilation is provided. Open motors that

have commutators or collector rings shall be located or protected so that sparks

cannot reach adjacent combustible material. Which of the following floor types is

prohibited for these type motors?

a. Concrete.

b. Metal covered

c. Wood

d. None of the above

4. When referring to the largest motor in a group of motors, which of the following is

the intent of the Code regarding this statement?

a. The Code is referring to the motor requiring the most amperes.

b. The Code is referring to the motor requiring the largest wire size.

c. The Code is referring to the motor requiring the most Full Load

Current.

d. The Code is referring to the motor requiring the most Full Load Ohms.


5. A 10 ft. motor feeder tap conductor must be enclosed either by an enclosed controller

or by a raceway, be not more than 10 feet in length, and, for field installation, be

protected by an overcurrent device on the line side of the tap conductor, the rating

or setting of which shall not exceed which of the following?

a. 100 percent.

b. 150 percent.

c. 500 percent.

d. 1,000 percent.

6. Conductors that supply a single motor used in a continuous duty application shall

have an ampacity of not less than which of the following?

a. 125 percent of the motor’s full-load current rating.

b. 250 percent of the motor’s full-load current rating.

c. 100 percent of the motor’s full-load current rating.

d. 300 percent of the motor’ full-load current rating.

7. Each motor used in a continuous duty application and rated more than 1 hp shall be

protected against overload by one of the following except for?

a. A separate Overload Device.

b. A Thermal Protector.

c. An Integral Protector.

d. An Interior Overcurrent Device.

8. A motor with a marked service factor of 1.15 shall have its overload heater

calculated at what percentage?

a. 100 percent

b. 250 percent

c. 300 percent

d. 125 percent

9. Thermally protected motors shall have ultimate trip currents of what percentage

when full-load currents are greater than 20 amperes?

a. 100 percent

b. 250 percent

c. 140 percent

d. 125 percent


10. Where fuses are used for motor overload protection, a fuse shall be inserted in

each of the following?

a. Branch circuit feeder conductors.

b. Main Circuit breaker bus bars.

c. Ungrounded Conductors.

d. Motor Control Conductors.

11. A three phase motor shall have an overload protection inserted in how many of

it’s phase conductors?

a. All three phase conductors.

b. All four phase conductors.

c. Both of it’s phase conductors

d. All non-current carrying phase conductors.

12. One pole of the disconnecting means shall be permitted to disconnect a permanently

grounded conductor, provided the disconnecting means is designed so that the

pole in the grounded conductor cannot be opened without which of the following

occurring?

a. Simultaneous disconnecting of all conductors of the circuit.

b. Simultaneous notification by alarm signal to the control circuit.

c. Simultaneous shut-down of the control circuit by electronic signal.

d. Simultaneous alert to a supervised system of the shut-down.

13. Where damage to a motor control circuit would create a hazard, then all

conductors of the control circuit that are outside the control device shall be

installed in accordance with which of the following?

I. In a raceway.

II. Protected from physical damage in other ways.

a. I only

b. II only

c. Either I or II

d. Neither I or II


14. For a portable motor rated at 1/3 horsepower or less, the controller for the motor

shall be permitted to be which of the following?

a. A detachable cord connector.

b. An attachment plug and receptacle.

c. A lockable plug and receptacle.

d. An SJO cord with locking attachment.

15. Find the feeder conductor ampacity for the three, single phase

(alternating current) motors listed below.

Two – 1 Hp, 230 volt, motors. One –

1 1/2 Hp, 230 volt, motor.

(Use Table 430-248)

16. Find the conductor ampacity for a 3/4 Hp, continuous duty, 120 volt, single

phase motor.

17. Complete the following requirements for a 15 Hp, 230 volt, 3-phase, induction

type, a-c motor with a service factor of 1.15, nameplate thermal protection at

125% of FLC and no code letter.

Full Load Current (Table-430-150)

Branch-Circuit Ampacity (430-22)

Disconnecting Means (430-110)

Overcurrent Protection (Table-430-152)

(Time delay fuse)

Heater Size (430-32)

(From Motor Nameplate)

(Not FLC of Motor/NEC)


MOTORS, CIRCUITS, AND CONTROLLERS

ARTICLE 430

LEVEL I

ANSWER KEY

1. b. 430.6(A)(1)

2. c. the motor control circuit 100

3. d. none of the above 430.14(B) Exception

4. c. Full-load current 430.24

5. d. 1,000 percent 430.28

6. a. 125 percent 430.22

7. d. an Interior Protective Device. 430.32(A)(1)(2)(3)

8. d. 125 percent 430.32(A)(1)

9. c. 140 percent 430.32 (A)(2)

10. c. Ungrounded conductor 430.36

11. a. In all three phase conductors Table 430.37

12. a. simultaneous opening of all conductors 430.105

13. c. Either I or II 430.73

14. b. an attachment plug and receptacle 430.81(B)

15. 28.5 [ 8 + 8 + ( 10 times 1.25 ) = 28.5 ] 430.24

16. 17.25 ( 13.8 times 1.25 = 17.25 ) 430.22(A)

17. (see following)

Full Load Current 42 amp (Table 430.250

Branch-Circuit Size 52.5 amp (430.22)

(42 times 125% = 52.5)

Disconnecting Means 48 amp [430.110(A)]

(42 times 115% = 48.3)

Overcurrent Protection 70 amp (Table 430.52)

(42 times 175% = 73.5 ; Go up to 80 ampere)

(Time delay fuse) 80 amp

Heater Size 52.5 amp (430.32)

(42 times 125% = 52.5)


AIR CONDITIONING AND REFRIGERATING EQUIPMENT

ARTICLE 440

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with requirements

regarding air conditioning and refrigeration equipment.

INTRODUCTION:

This Article will identify areas of concern regarding ampacity requirements for air

conditioning equipment, branch circuit selection current, location and ground fault

protection including room air conditioners.

Hermetic Refrigerant Motor Compressor: A combination consisting of a

compressor and motor, both of which are enclosed in the same housing, with no

external shaft or shaft seals, the motor operating in the refrigerant.

In discussing this lesson, you may need to refer back to other articles such as:

430, 422, and 424.


Section 440.4 covers the nameplate requirements and should be studied carefully.

Single phase, 115 volt motor compressors rated in excess of 9 amperes locked

rotor or 4.5 amperes at 230 volts and all polyphase systems shall have nameplates

giving load currents.

If a motor is thermally protected, or in a thermally protected system, it shall be so

marked. Branch circuit short circuit and ground fault protective devices shall be

calculated by Part III.

The inspector should be able to locate, read and properly apply the nameplate

information given by the manufacturer. In studying Section 440.7, it may be

helpful to review Sections 430.24 and 430.53 Review the single machine concept

in Section 440.8.

The disconnecting means of a hermetic refrigerant motor compressor shall be

selected in a number of ways. See Section 440.12(A) for details. Combination

loads are covered in 440.12(B). All switches in circuits must comply with 440.12.

A cord and plug is permitted as disconnect means for equipment such as room air

conditioners , refrigerators, freezers, etc.

The location of disconnecting means shall be located within sight from and


readily accessible from the air conditioning or refrigerating. (440.14)

Rating or settings for individual motor compressors are not to exceed 175% of

rated load current or branch circuit selector current whichever is greater. It may

be increased to 225% if necessary for starting current. [440.22(A)]

Protective devices must meet manufacturer’s values for overload. [440.22(C)]

Branch circuit conductor ampacity must be at least 125% of rated load current or

branch selection current whichever is greater. (440.32)

Feeder ampacity of multimotor installations must be the sum of all motor

ampacities plus 25% of the largest. See exceptions. (440.33)

For combinations loads see 440.34.

Motor compressors and branch circuit overload protection shall be according to

one of the following[440.52(A)]:

1. Overload relay 140% of load.

2. Integral thermal protection.

3. Fuse or inverse time circuit breaker 125% of load.

4. Protective system furnished for use with specific motor compressor.

Briefly review overload relays and motor compressors in Sections 440.53 and

440.54, respectively. Attachment plug ratings are not to exceed 20 amperes at

125 volts, or 15 amperes at 250 volts. [440.55(B)]

Room air conditioners rated not over 250 volts, single phase are covered under

part VII and over 250 volts or 3 phase shall be directly connected. (440.60)

Consider single motor unit when all four conditions are meet. See 440.62(A & B).

440.62(B) states that a plug-connected room air conditioner shall not exceed 80%

of the branch circuit.

Attachment plugs may be permitted as disconnecting means if meeting conditions

of Section 440.63. Briefly mention supply cords in Section 440.64.

APPLICATION:






ARTICLE 440

LEVEL I

WORKSHEET

1. A room air conditioner shall be permitted to be cord and plug connected

if not rated over which of the following?

a. 40 amperes and 250 volts, single phase.

b. 30 amperes and 240 volts, single phase.

c. 20 amperes and 230 volts, single phase

d. 15 amperes and 220 volts, single phase.

2. An attachment plug and receptacle shall be permitted to serve as the

disconnecting means for a single-phase room air conditioner rated 250 volts

or less if which of the following is applied?

I. The manual controls on the room air conditioner are readily

accessible and located within 1.8 m (6 ft) of the floor

II. An approved manually operable disconnecting means is installed in a

readily accessible location within sight from the room air conditioner.

a. I only

b. II only

c. Either I or II

d. Neither I or II

3. What is the maximum length flexible cord permitted for a nominal 240

volt room air conditioner?

a. 6 feet

b. 8 feet

c. 10 feet

d. 12 feet


4. Which of the following situations would require a nameplate on a 115

volt motor compressor?

a. When the locked-rotor current of each single-phase motor-compressor

has a rated-load current of more than 9 amperes at 115 volts.

b. When the locked-rotor current of each single-phase motor-compressor

has a rated-load current of less than 9 amperes at 115 volts.

c. When the locked-rotor current of each single phase motor-compressor

exceeds a rated load-current of 6 amperes or greater at 115 volts.

d. When the locked-rotor current of each single-phase motor-compressor

has a rated-load current of more than 10 amperes at any voltage.

5. For a wye-start, delta-run connected motor-compressor, the selection of

branch-circuit conductors between the controller and the motor-

compressor shall be permitted to be based on what percentage of either

the motor-compressor rated-load current or the branch-circuit selection

current, whichever is greater?

1. 125 percent

2. 75 percent

3. 72 percent

4. 80 percent

6. Rating or settings for individual motor compressors are not to exceed

175% of rated load current or branch circuit selector current

whichever is greater. It may be increased to which of the

following if necessary for starting current?

a. 150 percent

b. 250 percent

c. 300 percent

d. 225 percent

7. Motor compressors and branch circuit overload protection shall be

according to which of the following?

a. Overload relay 140% of load.

b. Integral thermal protection.

c. Fuse or inverse time circuit breaker 125% of load.

d. Protective system furnished for use with specific motor compressor.

E. Any of the above.


8. The motor-compressor branch-circuit short-circuit and ground-fault

protective device shall be capable of carrying which of the following?

a. The starting current of the motor.

b. The starting surge of the compressor.

c. The ampacity of the motor-controller center.

d. The total load of the compressor, fans and controls.

9. A controller shall be marked with data as may be needed to properly

Indicate the motor-compressor for which it is suitable to include


a. The manufacturer’s name, trademark, or symbol.

b. Identifying designation.

c. Voltage; phase; full-load and locked-rotor current (or horsepower)

rating;

d. All of the above

10. The provisions of Part III specify devices intended to protect the branch-

circuit conductors, control apparatus, and motors in circuits supplying hermetic

refrigerant motor-compressors against overcurrent due to short circuits and

grounds. They are in addition to or amendatory of the provisions of which of the

following?

a. Article 240.

b. Article 300.

c. Article 250.

d. Article 440.

11. Conductors supplying a motor-compressor load as a combination load

shall have an ampacity sufficient for the appliance load plus the

required ampacity for the additional lighting or appliance load as

calculated from which of the following?

a. Article 210 and other applicable articles.

b. Article 220 and other applicable articles.

c. Article 300 and other applicable articles.

d. Article 422 and other applicable articles.

12. The ampere rating of a disconnecting means for a Hermetic Refrigerant

Motor-Compressor shall be at least which of the following

percentages of the rated-load current or branch-circuit selection

current which ever is greater.

a. 250%

b. 150%

c. 125%


d. 115%

13. AC disconnecting means must be located within which of following

distances from the equipment. (Without Exceptions)

a. within 35 feet

b. within sight

c. within 40 feet

d. within 25 feet

14. A motor-compressor is protected by a separate overload relay protective

Device that is responsive to motor-compressor current. This type

protection is allowed if the device is set to trip at a percentage not to

exceed which of the following?

a. 140%

b. 175%

c. 125%

d. 225%

15. A motor-compressor is also allowed to be protected by a fuse or inverse

time circuit breaker responsive to motor current, which shall also be

permitted to serve as the branch-circuit short-circuit and ground-fault

protective device. This device shall be rated at not more than which of the

following?

a. 125% of the motor-compressor rated-load current.

b. 175% of the motor-compressor rated-load current

c. 225% of the motor-compressor rated-load current

d. 250% of the motor-compressor rated-load current

16. Branch circuit conductors supplying a single motor-compressor shall

have an ampacity of which of the following?

a. 125%

b. 150%

c. 115%

d. d. 175%


17. Overload relays and other devices for motor overload protection that are

not capable of opening short circuits shall be protected by which of the

following?

I. Fuses

II. Inverse time circuit breakers

a. I only

b. II only

c. Either I or II

d. Neither I or II

18. A room air conditioner that is rated as follows shall be directly

connected to wiring?

a. single phase and 250 volts

b. 3 phase and 250 volts

c. single phase and 120/240 volts

d. It is not required to be directly connected to wiring.

19. Where lighting units are also supplied along with a room air conditioner

the rating shall not exceed what percentage of the circuit.

a. 25%

b. 75%

c. 50%

d. 100%

20. Where no other loads are supplied, the total marked rating of a cord-and-

attachment-plug-connected room air conditioner shall not exceed which of the

following percentage of the rating of a branch circuit?

a . 50 %

b . 70 %

c . 80 %

d . 25 %



ARTICLE 440

LEVEL I

ANSWER KEY

1. a. 40 amperes and 250 volts single phase 440.62(A)


3. a, 6 feet 440.64

4. a. Locked rotor current in excess of 9 amperes. 440.4(A)

5. c. 72 percent 440.32

6. d. 225 percent 440.22

7. e, Any of the above. 440.52

8. a. The starting current of the motor 440.22(A)


10. a. Article 240 440.21

11. b. Article 220 and other applicable articles 440.34

12. d. 115% 440.12(A)(1)

13. b. within sight 440.14

14. a. 140% 440.52(A)(1)

15. a. 125% 440.52(A)(3)

16. a. 125% 440.32


18. b. 3 phase and 250 volts 440.60

19. c. 50% 440.62(C)

20. c. 80 % 440.62(B)


INTRINSICALLY SAFE SYSTEMS

ARTICLE 504

LEVEL I

OBJECTIVES:

After completing this lesson each student should be acquainted with the

requirements covering the installation of intrinsically safe apparatus and

wiring for class I, II, and III locations.

INTRODUCTION:

Wiring methods in hazardous locations can be extremely expensive. For

economical reasons, more I.S. wiring was being used which brought about

the need for specific regulations covering such installations.


1. Thoroughly cover the requirements included in scope, equipment

approval, and the definitions included within the Article.

2. Point out the importance of complying with installation

limitations that

may be in the instructions included with the equipment listing and/or

included with Section 504.10(A) as to location.

3. Cover the remaining material included in the article which proved

installation specifics.

r. Use manufacture’s literature, pictures, and samples to more thoroughly

illustrate the intended application and installation methods.

APPLICATION:

If time allows, let the class answer questions on the worksheet.





ARTICLE 504

LEVEL I

WORKSHEET

1. All of the following terms are included in the definitions in Section 504.2 except:

a. Control Drawing

b. Associated Apparatus b.

Intrinsically Safe System d.

Cold Arc Circuit

2. Conductors and cables of intrinsically safe circuits run in other than raceway

or cable tray systems shall be separated by at least which of the following

distances and secured from conductors and cables of any non-intrinsically safe

circuits?

a. 2 inches

b. 4 inches

c. 6 inches

d. 8 inches

3. The maximum spacing between labels used to identify “Intrinsic Safety Wiring”

is:

a. 6 inches

b. 24 inches

c. 6 feet

d. 25 feet

4. The clearance between two terminals for connection of field wiring of

different intrinsically safe circuits shall be at least what distances apart unless

this clearance is permitted to be reduced by the control drawing?

a. 1.25 inches

b. 1.00 inches

c. .75 inch

d. .25 inch



ARTICLE 504

LEVEL I

ANSWER KEY

1. D, Cold Arc Circuit 504.2

2. A, 2 inches 504.30(A)(3)

3. D, 25 feet 504.80(B)

4. A .25 (1/4 inch) 504.30(B)


MOTOR FUEL DISPENSING FACILITIES

ARTICLE 514

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with wiring

requirements of service stations and other gasoline dispensing establishments.

MATERIALS NEEDED:

Samples of explosion proof fittings and seal-offs.

INTRODUCTION:

Service stations include any place where volatile flammable liquid is transferred

to fuel tanks of self-propelled vehicles. Special care is taken in around these areas

because a spark could set off an explosion.


Look at the Table 514.3(B)(1) and go over the different areas as to their

classification.

All wiring in the class I location as determined in Table 514.3(B)(1) shall meet the

requirements set forth in Article 501. (514.4)

All wiring above the hazardous locations shall have the wiring meet the same

requirements as commercial garages described in 511.7. (514.7)

All conductors going to the gas pump including the neutral shall be disconnected at the

same time. (514.5)

Discuss emergency controls as outlined in 514.11(B & C).

Provisions for maintenance and service of dispensing equipment are outlined in

514.13.

Seal-off fittings shall be provided as the first fitting out of the ground at the dispenser

or cavity or enclosure also at the boundary of the hazardous location.

The sealing compound shall be approved for the application used. (514.9)

All metal parts of pumps, raceways, and any non-current carrying parts shall be

grounded per Article 250. (514.16)


Underground wiring shall be installed in rigid metal conduit, threaded steel

intermediate conduit. Any wiring below a Class I Division II location shall be

considered a Class I Division I location. Rigid non-metal conduit shall be

permitted were under 2 feet of cover and terminates in a trench with rigid or

intermediate conduit for the last 2 feet of the conduit and run. Where rigid non-

metallic is used care is to be taken in that the junction box at the pump must have

built in grounding terminals. (514.8)

APPLICATION:





MOTOR FUEL DISPENSING FACILITIES

ARTICLE 514

LEVEL I

WORKSHEET

1. An underground tank vent opening is classified as a class I division I

where it discharges upward for which of the following?.

a. 10 feet

b. 12 feet

c. 6 feet

d. 5 feet

2. A motor fuel dispenser shall have a class I division II location for a

distance of up to 18 inches above grade and horizontally for which of the

following?

a. 20 feet

b. 10 feet

c. 5 feet

d. 3 feet

3. A remote outdoor pump has a class I division I location underground for

a distance of how far from the pump.

a. 10 feet

b. 20 feet

c. 15 feet

d. 5 feet

4. Disconnecting means for the gas pumps must disconnect?

a. only one of the ungrounded conductor

b. both of the ungrounded conductors

c. both ungrounded conductors and the grounded

d. the ungrounded conductors and the grounding conductors

5. Seal-offs shall be provided at which of the following in Class I

locations?

a. only at the pump

b. at the first fitting emerging from the earth and at the boundary

c. at the location where the conduit leaves the hazardous location

d. in any accessible location in the run to the pump


6. Type PVC conduit can be used if buried below grade at a minimum depth of__?

a. 12 inches

b. 18 inches

c. 20 inches

d. 24 inches

7. Each dispensing device shall be provided with a means to remove all external voltage

sources, including feedback, during periods of maintenance and service of the

dispensing equipment. The location of this means shall be permitted to be other than

inside or adjacent to the dispensing device. The means to remove all voltage sources

shall also meet which of the following?

a. Shall be capable of being locked in the open position.

b. Shall be rated at least 100 amperes.

c. Shall be within sight of the grounding electrode.

d. Shall cut off all the power, internal and external to the building.

8. Underground wiring shall be installed in threaded rigid metal conduit or

threaded steel intermediate metal conduit. Any portion of electrical wiring

that is below the surface of a Class I, Division 1, or a Class I, Division 2,

location [as classified in Table 514.3(B)(1) and Table 514.3(B)(2)] shall be

sealed within what distance of the point of emergence above grade.

a. 2 feet

b. 4 feet

c. 6 feet

d. 10 feet


MOTOR FUEL DISPENSING FACILITIES ARTICLE

514

LEVEL I

ANSWER KEY

1. d, 5 feet Table 514.3(B)(1)

2. a, 20 feet Table 514.3(B)(1)

3. a, 10 feet Table 514.3(B)(1)

4. c, both ungrounded conductors and grounded conductors 514.11(A)

5. b, as first fitting at pump and at 514.9(A & B)

hazardous location boundary.

6. d, 24 inches 514.8 Ex. No. 2

7. a, shall be capable of being locked in the open 514.13

position. 8. d, 10 ft. 514.8


HEALTH CARE FACILITIES ARTICLE

517

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with electrical construction

and installation criteria for general health care facilities such as doctor’s offices, dental

offices and emergency medical facilities.

MATERIALS NEEDED:

Examples of approved wiring methods.

INTRODUCTION:

Part A:

517.1, Scope

517.2, Definitions

Part B:

517.10(A), Applicability

517.11, General Installation/Construction Criteria

517.12, Wiring Methods

517.13, Grounding of Receptacles and Fixed Electrical Equipment

517.14, Panelboard Bonding


Wiring in patient care areas shall be installed in metal raceways or cable assemblies

approved for that purpose. [517.13(B)]

APPLICATION:

Allow the class time to answer questions on the worksheet.


Correct the worksheets and discuss the results.


HEALTH CARE FACILITIES

ARTICLE 517

LEVEL I

WORKSHEET

1. 517.10 Part II does not apply to:

a. Exam Rooms

b. Surgical Suites

c. Waiting Rooms

d. All of the above

2. In an area used for patient care operating at over 100 volts the grounding

conductor shall be:

a. An insulated copper conductor

b. An insulated aluminum conductor

c. An uninsulated copper conductor

d. An uninsulated aluminum conductor

3. Following the energizing of the Emergency System all the following

equipment, with the exception of which of the following shall be arranged for

delayed automatic connection to the alternate power source:

a. Central suction systems serving medical and surgical functions,

including controls. Such suction systems shall be permitted on the critical

branch.

b. Sump pumps and other equipment required to operate for the safety of

major apparatus, including associated control systems and alarms.

c. Closed circuit TV systems used for educational purposes.

d. Smoke control and stair pressurization systems, or both.

4. A system of circuits and equipment intended to supply alternate power to a limited

number of prescribed functions vital to the protection of life and safety is a(n);

a. life safety branch

b. essential electrical system

c. isolated power system

d. emergency system


HEALTH CARE FACILITIES

ARTICLE 517

LEVEL I

ANSWER KEY

1. c., Waiting Rooms 517.10 (B)(1)

2. a., An insulated copper conductor 517.13(B)

3. c. closed circuit TV systems used for educational purposes 517.34(A).

4. d. emergency system 517.2 Def.


PLACES OF ASSEMBLY

ARTICLE 518

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar special wiring

requirements in places of assembly as provided in Article 518.

MATERIALS NEEDED:

Handout of sections of the North Carolina State Building Code pertaining to places

of assembly.

INTRODUCTION:

A place of assembly is a building or portion of a building intended for the assembly

of 100 or more persons. If a room or space for assembly purposes is designed or

intended to be occupied by less than 100 persons it shall not be classified as a place of

assembly. For determining the area required per person consult the North Carolina

State Building Code.


Discuss wiring methods as covered in 518.4 for non-rated construction, rated

construction, and spaces with finish rating.

If any part of the place of assembly is classified as a hazardous area the wiring within

the hazardous location shall comply with the provisions of Article 500.

With the exception that approved flexible cables and cords shall be permitted to be laid

on floors where protected from contact by the general public, temporary wiring in

exhibition halls used for display booths, as in trade shows shall be installed in

accordance with Article 590.

The control of emergency systems shall comply with Article 700. Give the class some

time to review Article 590.

APPLICATION:





PLACES OF ASSEMBLY

ARTICLE 518

LEVEL I

WORKSHEET

1. Article 518 covers all building or portions of buildings or structures

designed or intended for the assembly of which of the following

number of persons?

a. 50 or more

b. 100 or more

c. 75 or more

d. 300 or more

2. Occupancy of any room or space for assembly purposes by less than 100

persons in a building of other occupancy, and incidental to such other

occupancy, shall be classified as which of the following?

a. Assembly occupancy.

b. Part of the other occupancy.

c. Coincidental Occupancy.

d. Non-incidental Occupancy.

3. Occupancy of any room for assembly purposes by 100 persons or more,

that contains a portable stage platform for the presentation of a musical

production shall comply with the applicable provisions of which of the

following?

a. Article 590

b. Article 518

c. Article 520

d. Article 511

4. Hazardous areas located in any assembly occupancy shall be installed in

accordance with which of the following?

a. Article 500

b. Article 590

c. Article 520

d. Article 518


5. Which of the following statements about temporary wiring in exhibition

halls used for display booths, as in trade shows is correct?

I. It shall be installed in accordance with Article 590.

II. Approved flexible cords shall be permitted to be laid on

floors where protected from contact by the general public.

a. I only

b. II only

c. Both I and II

d. Neither I or II

6. Which of the stipulations listed below must be met to permit electrical

nonmetallic tubing and rigid nonmetallic conduit to be installed in

club rooms, conference and meeting rooms in hotels or motels, courtrooms,

dining facilities, restaurants, mortuary chapels, museums,

libraries, and places of religious worship where the following

apply:

I. The electrical nonmetallic tubing or rigid nonmetallic

conduit is installed concealed within walls, floors, and

ceilings where the walls, floors, and ceilings provide a

thermal barrier of material that has at least a 15-minute

finish rating as identified in listings of fire-rated

assemblies.

II. The electrical nonmetallic tubing or rigid nonmetallic

conduit is installed above suspended ceilings where the

suspended ceilings provide a thermal barrier of material

that has at least a 15-minute finish rating as identified in

listings of fire-rated assemblies.

a. I only

b. II only

c. Neither I or II

d. Both I and II


PLACES OF ASSEMBLY

ARTICLE 518

LEVEL I

ANSWER KEY

1. b. 100 518.1

2. b. Incidental to whatever the occupancy is 518.2(B)

3. c. Article 520 518.2(C)

4. a. Article 500 518.3(A)

5. c. Both I and II 518.3(B)

6. d. Both 1 and 2 518.4(C)(1)(2)


MANUFACTURED BUILDINGS

ARTICLE 545

LEVEL I

OBJECTIVE:

After this lesson each student should be familiar with procedures for inspecting

concealed wiring installed at the factory.

MATERIALS NEEDED:

Pictures, slides, and plans for typical applications likely to be encountered.

INTRODUCTION:

Discuss the difference between manufactured buildings and manufactured homes

(mobile homes) – Article 550.

PRESENTING THE LESSON

1. When presenting the requirements included in this Article, be sure the students

have a clear understanding of the scope, Section 545.1 and the definitions included in

Section 545.2. *NOTE: North Carolina recognizes a third party testing agency label

which exempts the unit from local inspection. Regulations are available from NC

Department of Insurance Manufactured Building Division.

2. As a general rule requirements found in other Articles will be applicable

unless there is a different requirement included in Article 545 on the same

subject. When there is a difference, Article 545 will apply.

3. The requirements covered in Sections 545.4 through 545.9 are for the most part

the same as included in other code sections governing same subject, such as wiring

methods as recognized in Chapter 3, service entrance conductor and service

equipment as in Article 230, and boxes as included in Article 370.

NOTE: The requirements for the securing of cables and box dimensions permitted

in Section 545.4(B) and 545.9(A) differ slightly and these exceptions should be

pointed out.

4. Bonding and grounding requirements covered in Section 545.11 and 545.12

should be covered by making reference to Article 250.

5. The subject of component inter-connection is important and emphasis should be

placed on this subject both in the classroom and in the field. (545.13).

APPLICATION:





MANUFACTURED BUILDING

ARTICLE 545

LEVEL I

WORKSHEET

1. A Manufactured Building is a building that is of closed construction and is

made or assembled in manufacturing facilities on or off the building site

for installation, or for assembly and installation on the building site, other than


a. manufactured homes or recreational vehicles

b. mobile homes or park trailers

c. I only

d. Both I and II

2. In closed construction, cables shall be permitted to be secured only at

cabinets, boxes, or fittings where which of the following size conductors are

used and protection against physical damage is provided?

a. # 12 AWG and smaller

b. # 10 AWG and larger

c. # 12 AWG and larger

d. # 10 AWG and smaller

3. Pre-wired panels and building components shall provide for the bonding, or

bonding and grounding, of all exposed metals likely to become energized,

a. to the frame of the building and the ground rod.

b. in accordance with article 250, parts V, VI, and VII.

c. to the first means of disconnect.

d. to the grounding electrode.


MANUFACTURED BUILDING

ARTICLE 545

LEVEL I

ANSWER KEY

1. d. see definition of manufactured building 545.2

2. d. # 10 AWG and smaller 545.4(B)

3. b. in accordance with article 250, parts V, VI, and VII. (545.11)


AGRICULTURAL BUILDINGS

ARTICLE 547

LEVEL I

OBJECTIVE:

After this lesson each student should be familiar with special applications and

provisions of agricultural buildings as related to the Code.

MATERIALS NEEDED:

Pictures or slides of fixtures and enclosures suitable for dust, water, and corrosive

atmospheres and an equipotential plane being installed.

INTRODUCTION:

Agricultural buildings are places where excessive dust and water may accumulate such

as poultry or livestock confinements and grain elevators or storage barns. Many of these

areas may have a corrosive atmosphere due to different kinds of vapors emitted. Also,

some of these buildings are washed and sanitized with water and cleansing agents. These

conditions present a potentially dangerous environment for the use of electricity, so

precautions must be taken.


Section 547.3 clearly indicates that there are agricultural buildings or farm buildings not

of the types covered in Section 547.1(A & B) and they are intended to be wired

according to other applicable articles in the Code.

Sections 547.5 and 547.6 cover wiring methods, flexible connections and enclosures for

devices, relays, overcurrent devices and similar equipment required for agricultural

buildings governed by this Article.

Electrical motors and lighting fixtures should be designed for protection against

moisture, dust, etc. Guards should be used on lights to protect them from physical

damage and in some cases watertight guards should be used.

Section 547.9(B)(3) covers the important grounding requirements for agriculture

buildings. These requirements, and the equipotential plane requirements in 547.10 are

necessary as livestock within such facilities are generally highly vulnerable when

exposed to different voltage potentials. See Section 547.2 for the definition and an

explanation of an equipotential plane.


APPLICATION:






ARTICLE 547

LEVEL I

WORKSHEET

1. The provisions of this article shall apply to the following agricultural buildings or

that part of a building or adjacent areas of similar or like nature where excessive

dust and dust with water may accumulate, including all areas of which of the

following except?

a. Poultry buildings.

b. Livestock buildings

c. Fish confinement systems.

d. Pet shops.

2. Which of the following wiring methods is not allowed in agricultural

buildings?

a. UF cable

b. NMC cable

c. SE (copper)

d. NM cable

3. What is the minimum size of the bonding conductor required to connect the wire mesh

in a concrete floor of an animal confinement room to the building grounding

electrode system?

a . # 6 b . # 4

c . # 8

d . # 10

4. All 125-volt, single-phase, 15- and 20-ampere general-purpose receptacles installed

in the following locations, with the exception of which of the following, shall have

ground-fault circuit-interrupter protection for personnel?

a. Areas having an equipotential plane and a receptacle

b. Outdoor receptacles with weatherproof covers

c. A receptacle in an adjacent office area

d. Dirt confinement areas for livestock



ARTICLE 547

LEVEL I

ANSWER KEY

1. d. Pet shops 547.1 (A)

2. d, NM cable 547.5 (A)

3. c. # 8 547.10(B)

4. c. 547.5(G)


MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME

PARKS

ARTICLE 550

LEVEL I

OBJECTIVE:

After this lesson each student should be familiar with the requirements regarding

electrical installations within or on a mobile home or manufactured home and the wiring

in a mobile home park.

INTRODUCTION:

Discuss the definitions in Section 550.2 with emphasis on “Mobile Home”,

“Manufactured Home”, “Mobile Home Lot” and “Mobile Home Park”.

Discuss the requirements pertaining to the location of “Service Equipment for mobile

or manufactured homes. Refer to Part III.


Cover sample calculation for computing load for service and/or feeder assembly size.

[550.18]

Electrical distribution systems within the mobile home park must be 120/240 V, single

phase, 3 wire. The feeder to the mobile home park is calculated based on a lot demand of

the larger of (1) 16,000 VA or (2) the calculated load of the largest mobile home the lot

will accept. Load diversity among the lots can be accommodated by the application of

demand factors given in Table 550.31.

The students should review Article 550 with particular emphasis to exterior wiring systems

(i.e. feeders within the mobile home park, to the mobile home lot, and to the mobile home;

mobile home service equipment). New mobile homes, including the internal electrical

distribution systems, are inspected by a third party agent at the point of manufacture and

are not subject to local inspection. After the students have reviewed this Article to

familiarize themselves with the organization and information contained in this Article, the

instructor should review the Section in its entirety. Insure they understand how to do

calculations for MH for sizing feeder assemblies. Discuss example D11 in Annex D.

APPLICATION:





MOBILE HOMES AND MOBILE HOME PARKS

ARTICLE 550

LEVEL I

WORKSHEET

1. The power supply to a mobile home shall be a feeder assembly of:

a. Not less than 250-amp listed mobile home cords

b. A permanently installed feeder with 3 insulated conductors

c. a or b

d. Neither a nor b

2. When supplied with a feeder assembly consisting of a cord and cap:

a. The cap shall be listed for damp locations

b. The cord shall not be more than 21 feet long

c. The cord and cap shall have a minimum rating of 60A

d. The point of entrance may be in the roof

3. The mobile home disconnecting means shall:

a. Contain not more than 6 disconnects

b. Be located in the mobile home

c. Have provisions to accommodate accessory buildings

d. Not be mounted closer than 4 feet above finish grade or platform

4. Grounding of electrical and non-electrical metal parts shall be by means of:

a. Grounding the neutral bus in the distribution panel to made

electrodes: as per 250.83

b. Bonding the neutral bus to the ground bus and grounding either bus in

the distribution panel to "made electrodes: as per 250.83

c. Either a or b

d. Neither a nor b

5. Where a laundry area is provided, a branch circuit of what ampere rating shall be

provided?

a. 15 ampere

b. 20 ampere

c. 30 ampere

d. not required


6. In other than mobile home parks, secondary electrical distribution to the mobile

home lots may be:

a.120/208 V, 3 wire, derived from a 120/208, 34, 4 wire service

b. 120/240V, 34-4 wire taped from an auto transformer of 600 volts or less

c. 120/240/ 1 Phase, 3 wire

d. b or c

7. Mobile home service equipment may be located:

a. On the mobile home not more than 18 inches above grade

b. Up to 30 feet from the mobile home in a conspicuous location

c. Adjacent to and within 30 feet of the mobile home in a non-conspicuous

location

d. At the point of entrance of the feeder cable to the mobile home

8. Where outdoor or under-chassis line-voltage (120 volts, nominal, or higher)

wiring is exposed to moisture or physical damage, it shall be protected by any

of the following with the exception of which of the following?

a. rigid metal conduit.

b. intermediate metal conduit.

c. type MI cable, electrical metallic tubing, or rigid nonmetallic conduit

shall be permitted where closely routed against frames and equipment

enclosures.

d. EMT raceways.


MOBILE HOMES AND MOBILE HOME PARKS

ARTICLE 550

LEVEL I

ANSWER KEY

1. d, Neither a nor b 550.10(A)

2. d, The point of entrance may be in the roof 550.10(F)

3. b, Be located in the mobile home 550.11(A)

4. d, Neither a nor b 550.16

5. b, 20 ampere 550.12(C)

6. c, 120/240/ 1 Phase, 3W 550.4(B)

7. b, 550.32(A) 8. d, EMT raceways 550.15(H)

ARTICLE 550 EXAMPLE

A mobile home floor is 70 feet x 10 feet and has two small appliance circuits, a 100-

volt-ampere, 240-volt heater, 120-volt exhaust fan, 120-volt dishwasher, and a 7000-

volt-ampere electric range.

LIGHTING AND SMALL APPLIANCE LOAD

Lighting 70 x 10 x 3 x VA/sq. ft. = 2100 volt-amperes

Small appliance 1500 x 2 = 3000 volt-amperes

Laundry 1500 x 1 = 1500 volt-amperes

6600 volt-amperes

1st 3000 volt-amperes at 100% = 3000 volt-amperes

Remainder (6600-3000) at 35% = 1260 volt-amperes

4260 volt-amperes

4260 volt-amperes = 17.75 amperes per leg

240 volts

AMPERES PER LEG

A B

Lighting and Appliances 17.75 17.75

Heater, 100 VA/240 Volt = 4.2 4.2

Fan, 200 VA x 125%/120 Volt = 2.08

Dishwasher, 400 VA/120 Volt = 3.3

Range, 7,000 VA x .8/240 Volts = 23.3 23.3

Totals: 47.33 48.55

Based on the higher circuit calculated for either leg, a minimum 50-ampere supply cord is

required.


RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

ARTICLE 551

LEVEL I

OBJECTIVE:

After this lesson each student should be familiar with the requirements of the

wiring and equipment used in recreational vehicle parks.

MATERIALS NEEDED:

Information from dealers

INTRODUCTION:

Recreational vehicles are those used for temporary living for things such as

camping. These include motor homes, travel trailers, and truck campers. To get a

better idea of certain definitions in this Section, have students spend a few minutes

looking over the definitions in 551.2.


RV's are factory wired and due to their mobile nature are not available for

inspecting by AHJ therefore much of the material in part A need not be covered

in detail.

Have student look over definitions for recreational vehicle parks. (551.2)(A) All

125-volt, single-phase, 15- and 20-ampere receptacles shall have listed ground-fault

circuit-interrupter protection for personnel. A minimum of 70% of the sites shall be

equipped with a 30 amp 125 volt outlet with configuration per 550.15(C). All 125-

volt, single-phase, 15- and 20-ampere receptacles shall have listed ground-fault

circuit-interrupter protection for personnel. (551.71)

Calculations per site shall be based on the following:

Sites with both 20 and 30 amp supply, 3600 volts amps per site.

Sites with only 20 amps supply, 2400 volt amps per site.

The demand factors in Table 551.73 shall be applied for figuring the service and

feeders. Where park services exceed 240 volts the secondary panelboards shall be

treated as services. Site feeders shall be large enough for the load but not less

than 30 amps. [551.73(d)]

Where provided on back-in sites, the recreational vehicle site electrical supply


equipment shall be located on the left (road) side of the parked vehicle, on a line

that is 1.5 m to 2.1 m (5 ft to 7 ft) from the left edge (driver’s side of the parked

RV) of the stand and shall be located at any point on this line from the rear of the

stand to 4.5 m (15 ft) forward of the rear of the stand. [551.77(A)]

Equipment grounding shall be based on Table 250.122. Neutral shall not be used

for grounding on a recreational vehicle or vehicle site. (551.54)

Overhead open conductors shall have overhead vertical clearance of 18 feet and

horizontal clearance of 3 feet to all areas subject to recreational vehicle movement

(551.79). Underground conductors shall be protected from 18 inches below grade

up to termination . (551.80)

APPLICATION:





RECREATIONAL VEHICLES AND RECREATIONAL PARKS

ARTICLE 551

LEVEL I

WORKSHEET

1. The demand factor on 50 recreational vehicle sites to be applied to the

total load is which of the following?

a . 47%

b . 45%

c . 40%

d . 41%

2. In an RV Park, what percentage of all sites with electric supply must be

equipped with 30 ampere, 125 V receptacles?

a . 25% b . 50%

c . 70%

d . 100%

3. All 125-volt, single phase, 15 and 20 ampere receptacles provided for the

RV site are required to have which of the following?

a. GFCI protection for personnel.

b. Arc-fault circuit protection for personnel.

c. Arc-flash protection for personnel.

d. Grounding switches for personnel.

4. Where outdoor or under-chassis wiring is 120 volts, nominal, or over

and is exposed to moisture or physical damage, the wiring shall be

protected by rigid metal conduit, by intermediate metal conduit, or by

electrical metallic tubing, rigid nonmetallic conduit, - OR which of

the following type of cable, that is closely routed against frames and

equipment enclosures or other raceway or cable identified for the

application?

a. Type MI

b. Type NM

c. Type UF

d. Type NMC


RECREATIONAL VEHICLES AND RECREATIONAL PARKS

ARTICLE 551

LEVEL I

ANSWER KEY

1. d, Table 551.73

2. c, - 551.71

3. a, - 551.71

4. a, - 551.47 (G)


PARK TRAILERS

ARTICLE 552

LEVEL I

OBJECTIVE:

After this lesson the students should be familiar with the requirement of park

trailers.

INTRODUCTION:

Cover general rules for installations in article 552.


Discuss the scope and definitions in sections 552.1 and 552.2.

Cover requirements for power supply and feeders in sections 552.43 and 552.44(A).

APPLICATION:





PARK TRAILERS

ARTICLE 552

LEVEL I

WORKSHEET

1. The cord-exposed usable length shall be measured from the point of entrance to

the park trailer or the face of the flanged surface inlet (motor-base attachment

plug) to the face of the attachment plug at the supply end. What is the maximum

length of the power supply cord?

a. 23 feet

b. 28 feet

c. 40 feet

d. 36.5 feet

2. Dual-Voltage fixtures including luminaires or appliances having both 120-volt

and low-voltage connections shall be listed for dual voltage. Which of the

following shall not be used to supply the voltage?

I. Autotransformer

II. Voltage Converter

a. I only

b. II only

c. Both I and II

d. Neither I or II

3. Feeder supply cords shall have a minimum ampere rating of which of the

following?

a. 50 amperes

b. 100 amperes

c. 60 amperes

d. 30 amperes

4. Each 125-volt, single-phase, 15- or 20-ampere receptacle shall have ground-

fault circuit-interrupter protection for personnel in which of the following

locations?

a. Where the receptacles are installed to serve kitchen countertop

surfaces

b. Receptacles installed within 5 ft. of a metal water pipe.

c. Receptacles serving dining room circuits

d. Receptacles for interior holiday lighting.


PARK TRAILERS

ARTICLE 552

LEVEL I

ANSWER KEY

1. d. 36.5 feet 552.44(B)

2. a. I only 552.20 (E)

3. d. 30 amp. 552.43 (A)

4. a. 552.41 (C)(1)


FLOATING BUILDINGS

ARTICLE 553

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with the

requirements of floating buildings.

INTRODUCTION:

The general rules and requirements for installations are covered by Article 553.


Cover scope and definition of section 553.1 and 553.2.

Discuss the location of service equipment in section 553.4.

Discuss the installation of services and feeders in section 553.7.

APPLICATION:





FLOATING BUILDINGS

ARTICLE 553

LEVEL I

WORKSHEET

1. The service to a floating building shall be located?

a. on the floating building

b. adjacent to but not in or on the floating building or structure.

c. both a and b

d. neither a nor b

2. Which of the following wiring methods shall not be used as a feeder when

flexibility is required?

a. liquidtight flexible metal conduit

b. liquidtight flexible nonmetal conduit

c. liquidtight nonmetallic conduit

d. extra-hard usage portable power cable


FLOATING BUILDINGS

ARTICLE 553

LEVEL I

ANSWER KEY

1. b, -. 553.4

2. c, - 553.7(A & B)


MARINAS AND BOATYARDS

ARTICLE 555

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with the general

requirements of electrical installation in Marinas and Boatyards.

INTRODUCTION:

The number of installations covered by Article 555 is increasing rapidly and the

importance of proper understanding and application of these safety regulations cannot

be over emphasized. There have been a number of electrocutions on such installations

in North Carolina that could have been avoided provided applicable safety requirements

had been incorporated in the original installation. Maintenance of these installations is

also a very important part of the "safety package."

Many of the recreational facilities covered in the scope of Article 555 will be found

in locations where corrosion is a very difficult problem. Samples of outdoor

equipment which has been designed and listed for such use will be helpful when

evaluating proper application of the necessary components.


The scope and application of other Articles in Section 555.1 and 555.2 need to be

reviewed with the students.

The requirements in Section 555.19 cover receptacles which are divided into two classes

of use; (1) Those which provide shore power to the boats and (2) Those which are for use

in maintenance and other purposes. The safety requirements for each are different and

consequently must be thoroughly understood.

Permitted wiring methods are given in Section 555.13 and should be thoroughly

discussed.

A great deal of emphasis should be placed on covering the grounding requirements

included in Section 555.15. Applicable requirements in Article 250 should also be

reviewed.

Wiring over and under navigable water is subject to the approval of governmental

agencies, such as the Coast Guard and Army Corps of Engineers.


The requirements included in Sections 555.21 pertain to Gasoline Dispensing and should

be reviewed carefully.

APPLICATION:






ARTICLE 555

LEVEL I

WORKSHEET

1. Shore power for boats shall be provided by single receptacles rated not less

than which of the following?

a. 15 amperes

b. 30 amperes

c. 40 amperes

d. 50 amperes

2. Disconnecting means shall be provided to isolate each boat from its supply

connection(s). The disconnecting means shall be readily accessible and mounted

not more than which of the following from the receptacle it controls?

a. Not greater than 6’7” above the deck surface

b. 24 inches

c. Not less than 12 inches above the deck surface

d. 30 inches

3. Twenty shore power receptacles rated 20 amperes and 120 volts will be supplied

from one panel. The minimum ampacity for the 120/240 volt feeder is which of

the following?

a. 70 amperes

b. 140 amperes

c. 200 amperes

d. 280 amperes

4. When grounding metal boxes and cabinets at a marina which of the following is the

minimum size and type of equipment grounding conductor permitted?

a. #12 insulated copper

b. # 12 insulated aluminum

c. # 12 insulated conductor

d. # 12 bare copper


5. All electrical connections shall be located at least 12 inches above the deck of

a floating pier. All electrical connections shall be located above the electrical

datum plane and at least what height above the deck of a fixed pier?

a. 30 inches

b. 24 inches

c. 36 inches

d. 12 inches

6. Electrical wiring and equipment located at facilities for the repair of marine

craft containing flammable or combustible liquids or gases shall comply with

which of the following in addition to the requirements of this article?

a. Article 511

b. NFPA 110

c. The Local fuel distributor’s regulations.

d. NFPA 101



ARTICLES 555

LEVEL I

ANSWER KEY

1. b. 30 ampere 555.19(A)(4)

2. d. 30 inches 555.17(B)

3. a. 140 amps;

20 x 20 = 400 x 70% = 280 amps

280 amps x 120 volts = 33,600 VA

33,600 VA / 240 volt = 140 amps 555.12 and Table 555.12

4. c. #12 insulated conductor 555.15(C)

5. d. 12 inches 555.9

6. a. Article 511 555.22


TEMPORARY INSTALLATIONS

ARTICLE 590

LEVEL I

OBJECTIVE:

After completing this lesson, each student should understand the purpose of

temporary wiring, when and where it is permitted, and the difference between

temporary and permanent wiring.

INTRODUCTION:

The contents of this lesson will deal with temporary electrical power and lighting wiring

methods which may be of a class less than would be required for a permanent

installation.


Time periods in which temporary wiring may be used include: (1) during the period of

construction, (2) 90 days for certain temporary wiring, (3) emergencies and tests, and (4)

during the removal of temporary wiring.

Discuss Section 590.3 in detail.

Highlight the prohibition within Section 590.4 against installing directly on the

floor or ground those cable assemblies and flexible cords used as temporary

branch circuits or feeders; note the exception for extension cords.

Discuss Section 590.6 concerning ground-fault protection for personnel.

APPLICATION:






ARTICLE 590

LEVEL I

WORKSHEET

1. Temporary electrical power and lighting installations shall be permitted for a

period not to exceed which of the following for holiday decorative lighting and

similar purposes?

a. Whatever is set by the AHJ.

b. 120 days

c. 30 days

d. 90 days

2. Conductors shall be permitted within cable assemblies or within multiconductor

cords or cables used in temporary installations shall be of a type identified for


a. Hard usage or extra-hard usage.

b. Junior hard usage.

c. RHSJO

d. USE

3. Receptacles on construction sites shall not be on branch circuits which supply


a. Temporary branch circuits.

b. Temporary heat or ventilation.

c. Temporary battery charging units.

d. Temporary lighting.

4. Under which of the following conditions can vegetation be used for support

of branch circuit conductors or cables for holiday lighting?

I. The use of proper strain-relief devices.

II. The use of tension take-up devices.

a. I only

b. II only

c. Both I and II

d. Neither I or II



ARTICLE 590

LEVEL I

ANSWER KEY

1. d. 90 days 590.3(B)

2. a. hard usage or extra hard usage 590.4(C)

3. d. temporary lighting 590.4(D)

4. c. both I and II 590.4(J) Exception


ELECTRIC SIGNS AND OUTLINE LIGHTING

ARTICLE 600

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with the special

wiring requirements of electric signs and outline lighting.

MATERIALS NEEDED:

Pictures of electric signs.

INTRODUCTION:

Cover appropriate definitions from article 100.

(1) Electric sign: a fixed, stationary, or portable self-contained, electrically

illuminated utilization equipment with words or symbols designed to convey

information or attract attention.

(2) Electric-discharge Lighting: systems of illumination utilizing fluorescent

lamps, high-intensity discharge (HID) lamps, or neon tubing.

(3) Outline lighting: an arrangement of incandescent lamps, electric discharge

tubing or other electrically powered light sources to outline or call attention to

certain features such as the shape of a building or the decoration of a window.

This lesson covers special wiring needed for special types of equipment.

Remember that Chapter 6 supplements or modify the general rules. Chapters 1

through 4 apply except as amended by Chapter 6 for the particular conditions.

This lesson is concerned with 1000 volts and less.


Article 600 covers the installation of conductors and equipment for electrical signs

and outline lighting.

Discuss definitions of; neon-tubing; section sign; sign body; skeleton tubing

(600.2).

Signs, unless approved by special permission, must be listed, provided with

installation instructions and installed according to that listing (600.3).


Each commercial building and each commercial occupancy accessible to pedestrians

shall be provided at an accessible location outside the entrance to each occupancy with

at least one outlet for sign or outline lighting use. This outlet shall be supplied by a

branch circuit which supplies no other loads.

The branch circuit must be rated at least 20 amperes. Circuits that supply neon tubing

shall not be rated in excess 30 amps. Circuits that supply all other signs and outline

lighting shall not exceed 20 amps. (600.5)

Wiring methods used to supply signs and outline lighting shall terminate within a sign or

system enclosure. Signs and transformer enclosures shall be permitted as pull or junction

boxes to supply adjacent signs or outline lighting system. Metal poles used to support

signs shall be permitted to enclose conductors provided poles and conductors are

installed per 410.30(B).

Each outline lighting installation and each sign shall be controlled by an externally

operable switch or circuit breaker that will open all ungrounded conductors. Emphasize

that this disconnecting means shall be located at the point where the feeder circuit or

branch circuit(s) supplying a sign or outline lighting enters a sign enclosure or pole and

must disconnect all wiring. (600.6)

Switches, flashers, and similar devices controlling transformers shall either be rated for

controlling inductive loads or have an ampere rating not less than twice the ampere

rating of the transformer. AC general use snap switches shall be permitted to be used on

AC circuits to control inductive loads not exceeding the ampere and voltage rating of

the switch. [600.6(B)] (See 404.14)

Metal equipment of signs, outline lighting, and skeleton tubing must be grounded. Listed

flexible metal conduit or listed liquidtight flexible metal conduit that encloses secondary

conductors of a transformer or power supply for use with neon tubing shall be permitted

as the bonding means if the total length does not exceed 100 feet. Where flexible

nonmetallic conduit or tubing is used a bonding conductor is required and shall meet the

following: (1) be spaced at least 1-1/2 inches from the conduit when the circuit is

operated at < 100 Hz or 1-3/4 inches if > 100 Hz (2) installed separate from the flexible

non-metallic conduit (3) Copper not smaller than #14 and protected from physical

damage if installed external to sign or raceway. (600.7)

Enclosures shall have ample strength and rigidity made of metal or be listed. The

minimum thickness for sheet copper or aluminum shall be 0.020 inches and 0.016 inches

for sheet steel. Metal parts must be protected against corrosion. (600.8)

A sign or outline lighting system shall be located at least 14’ above areas accessible to

vehicles unless protected from physical damage. Neon tubing readily accessible to

pedestrians shall be protected from physical damage. Adjacent combustible materials

shall not be subject to temperatures in excess of 90 degrees Celsius. The spacing between

wood and other combustible material in incandescent or HID lamp or lamp holder shall

not be less than 2”. [600.9]


Sign and outline lighting systems in wet location shall be weather proof and have a drain

hole in the low point or isolated section no larger than 1/2 “ or smaller than 1/4” and be

positioned so there can be no external obstructions. [600.9(D)]

Portable or mobile signs shall be adequately supported and readily removable without

tools. Attachment plugs shall be provided for each sign. In wet or damp locations cords

shall be for hard service or hard service types and have an equipment grounding

conductor. The cord shall be one designated in table 400-4. The cord shall not exceed

15’. [600.10(D)]

Ballasts, transformers, electronic power supplies and Class 2 power sources shall be

securely fastened in place as near to the lamps or neon tubing as practicable. If in a wet

location then they must be weather proof or be listed for outdoor use. A work space of

3’ high 3’ wide and 3’ deep shall be provided at each ballast, transformer, electronic

power supply and Class 2 power source where not installed in a sign. Ballasts,

transformers, electronic power supplies and Class 2 power sources shall be permitted in

attic spaces where there is an access door and passageway to the ballast of at least 3’ X

2’ and a 12” suitable permanent walkway extending from the point of entry. Ballasts,

transformers, electronic power supplies and Class 2 power sources in suspended ceiling

are not to be supported by ceiling grid and are not connected to the branch circuit by

flexible cord. (600.21)

Ballast shall be listed for use. Transformers and electronic power supplies shall have

secondary ground-fault protection except for (1) transformers with isolated ungrounded

secondaries and maximum open circuit voltage < 7500 volts (2) transformers with

integral porcelain or glass secondary housing for neon tubing requiring no field wiring.

Secondary voltage shall not exceed 15,000 volts and the voltage to ground of any output

terminal shall not exceed 7500 volts. The secondary current rating shall have a

secondary current rating of not more than 300 milliamperes. Secondary circuits shall not

be connected in paralleled or in series. (600.23)

Neon secondary circuit conductors, 1000 volts or less shall use wiring in chapter

3. Conductors shall be insulated not smaller than # 18. The number of conductors in

a raceway shall be in accordance with Table 1 of Chapter 9. (600.31)

Neon secondary conductors over 1000 volts must be installed per 600.32(A). Conductors

shall be separated from each other and from other objects by spacing not less than 1 1/2”.

The insulation on all conductors shall extend beyond the conduit not less than 2 1/2”.


Terminals of electrodes shall not be accessible to unqualified persons. The neon tubing

shall be supported not more than 6” from the electrode connection.

APPLICATION:






ARTICLE 600

LEVEL I

WORKSHEET

1. Which of the following statements about sign disconnects is correct?

I. Without exception each outline lighting installation and each sign shall

be controlled by a switch that is in sight of the sign.

II. If not rated for controlling inductive load(s) flashers controlling

transformers shall have an ampere rating not less than twice the ampere

rating of the transformer.

a. I only

b. Both I and II

c. II only

d. Neither I or II

2. All of the following are true of wiring methods for outdoor electric signs

EXCEPT for which of the following?

a. The wiring method shall terminate within the sign or in a suitable

enclosure.

b. Signs shall not be permitted to be used as pull or junction boxes when

they contain both branch and secondary circuit conductors, which

supply the light.

c. Metal poles that support the sign may be permitted to enclose supply

conductors.

d. Wiring methods for electric signs and outline lighting must comply

with 600.5 (C) 1, (C) 2, and (C) 3 and Article 410.30(B).

3. Which of the following statement is correct regarding outdoor signs?

I. Each commercial building shall be provided at an accessible location outside

the occupancy with at least one outlet for sign and or outlet lighting use.

II. The required sign outlet for commercial buildings and commercial occupancy

shall be supplied by a 20 ampere branch circuit, which supplies no other load.

a. Both I and II

b. I only

c. II only

d. Neither I or II


4. Which of the following statements about branch circuits for signs or outline

lighting is correct?

I. Circuits which supply other than neon tubing installations shall be rated

not to exceed 20 amperes.

II.Circuits supplying neon tubing installations shall not be rated in excess

of 30 amperes.

a . I

b . Both I and II

c . II only

d . Neither I or II

5. Signs and outline lighting systems shall be marked with the manufacturer’s

name, trademark, or other means of identification as well as which of the

following?

a. Input voltage and current rating.

b. Ampacity and Hertz.

c. Resistance and Cycles per Second.

d. Point of purchase.

6. A section sign is a sign or outline lighting system is which of the following?

a. A sign that is engineered in the field.

b. A sign that is assembled by sheet metal craftsmen in the field.

c. A sign that operates at 50 volts or less.

d. A sign that is shipped as sub-assemblies and requires field installed

wiring between the sub-assemblies to complete the overall sign.

7. Which of the following statements about sign enclosures is correct?

I. Minimum thickness for sheet copper shall be NO. 26 MSG if ribbed,

corrugated, or embossed.

II. Minimum thickness for sheet steel is .028 inch.

a. I only

b. II only

c. Both I and II

d. Neither I or II


8. Signs and outline lighting system equipment for wet location use, other than

listed watertight type, shall be weatherproof and have drain holes, as

necessary, in accordance with the following EXCEPT?

a. Drain holes shall not be larger than 1⁄2 inch or smaller than 1⁄4 inch.

b. Every low point or isolated section of the equipment shall have at least

one drain hole.

c. Drain holes shall be positioned such that there will be no external

obstructions.

d. Drain holes shall be placed no more than 6” apart.

9. Portable or mobile signs shall have a factory installed ground-fault interrupter

as an integral part of the attachment plug, or shall be located in the power-supply

cord within what distance of the attachment plug.

a. 5 inches

b. 5 feet

c. 12 feet

d. 12 inches

10. Secondary circuit conductors 1000 volts or less shall be listed, insulated, and not

smaller than.

a. 18 AWG

b. 16 AWG

c. 14 AWG

d. 12 AWG



ARTICLE 600

LEVEL I

ANSWER KEY

1. c. II only 600.6(B)

2. b. 600.5(C)(2)

3. c. II only 600.5(A)

4. b. Both I and II 600.5(B)(1 & 2)

5. a. Input voltage and current rating 600.4a

6. d 600.2

7. d. 600.8(C)

8. d. 600.9(D)

9. c, 12 inches 600.10(C)(2)

10. a. 18 AWG 600.31(B)


OFFICE FURNISHINGS

ARTICLE 605

LEVEL I

OBJECTIVE:

After completing this lesson each student should be familiar with the

requirements related to office furnishings including lighting accessories and wired

partitions.

MATERIALS NEEDED:

Handouts or pictures showing office partitions and of wiring methods used in

connecting partitions.


It is important that the scope included in Section 605.1 be understood. Sections

605.2 through 605.4 covers general wiring methods, conductor and permitted

materials for the wiring system and their interconnection.

Section 605.2 has a new definition: Office furnishings. Emphasis needs to be given for

the new definition. Section 605.5 covers the types of Office furnishing interconnections

and the use of flexible cords. Section 605.6 covers the lighting equipment permitted for

the partition and requires such to be listed. Note that receptacles in fixtures are not

permitted.

Sections 605.7 through 605.8 covers the different types of partitions and the

permitted methods of providing power to the same.

APPLICATION:





OFFICE FURNISHINGS

ARTICLE 605

LEVEL I

WORKSHEET

1. Under which of the following circumstances does the N.C. Electrical

Code allow relocatable wired partitions to extend from floor to

ceiling?

a. Where permitted by the manufacturer of the panels.

b. Where permitted by the appropriate referenced standard.

c. Where permitted by express request in writing.

d. Where permitted by the authority having jurisdiction

(AHJ).

2. Which of the following is not allowed in lighting equipment

accessories for cord and plug connected wired partitions?

I. Convenience receptacles.

II. 18 AWG wiring.

a. I only

b. II only

c. Both I and II

d. Neither I nor II

3. Individual office furnishings of the freestanding type, or groups of office furnishings that are electrically connected, are mechanically

contiguous, and do not exceed 30 feet when assembled, shall be permitted

to be connected to the building electrical system by which of the

following?

a. A single flexible cord and plug.

b. A multi-wire branch circuit.

c. A non-metallic sheathed cable assembly.

d. A flexible cord with # 14 AWG conductors.


4. Which of the following is not correct of partition

interconnections for office furnishings?

a. The cord is extra-hard usage type 14 AWG or larger

conductors, with an insulated grounding conductor.

b. The partitions are mechanically contiguous.

c. The cord is not longer than necessary for maximum

positioning of the partitions but is in no case to exceed

2 feet.

d. The cord is terminated at an attachment plug and cord

connector with strain relief.

5. Multiwire branch circuits supplying power to permanently connected

freestanding partitions shall be provided with a means to disconnect

simultaneously all ungrounded conductors at which of the following

locations?

a. Shall not contain multiwire circuits.

b. The panelboard where the branch circuit originates.

c. The main distribution panelboard.

d. The first means of disconnect for the sub-fed panel.


OFFICE FURNISHINGS

ARTICLE 605

LEVEL I

ANSWER KEY

1. d. 605.2 Exception 605.2

2. a. I only 605.5(C)

3. a. a single flexible cord and plug 605.8 605.9

4. a 605.4 605.5

5. a. Not permitted 605.9 (D)


SWIMMING POOLS, FOUNTAINS, AND SIMILAR INSTALLATIONS

ARTICLE 680

LEVEL I

OBJECTIVES:

After completing this lesson each student should be familiar with:

1. the requirements that apply to the construction and installation of electric

wiring for various types of pools and fountains.

2. the specific wiring requirements for auxiliary equipment such as pumps

and filters.

INTRODUCTION:

In this Article, the term "pool" includes: swimming, wading, and permanently installed

therapeutic pools. "Fountains" refer to fountains, ornamental pools, reflection pools, and

display pools. Those sections covered in this lesson plan are the most important for a

level one class.


Review definitions in Section 680.2. Make sure the students have a good idea of the

terms in this Section.

Discuss section 680.5 on ground – fault circuit – interrupters.

Review the requirement on grounding in section 680.6.

Many restrictions exist on the location of overhead conductors. Note these

requirements and their exceptions. See Section 680.8 for underground wiring

locations.

Study carefully the requirements for underwater lighting fixtures installed below the

normal water level of the pool. Explain the wiring methods and materials for Wet-Niche,

Dry-Niche, and No-Niche fixtures. (680.23)

Review the requirements for junction boxes and enclosures for transformers or

ground fault circuit interrupters in Section 680.24.

Explain the bonding requirements for all pool associated equipment. Also cover the

minimum size and type of bonding conductors required in Section 680.26.

Briefly discuss storable pools. (680.30)


Cover Section IV in detail because indoor installations of spas and hot tubs are

very popular areas of wiring.

Briefly discuss the rest of this Article and have the class read it. The use of

handouts and materials may be very helpful in this Article.

APPLICATION:






ARTICLE 680

LEVEL I

WORKSHEET

1. A permanently installed bathtub equipped with a re-circulating piping system,

pump, and associated equipment. It is designed so it can accept, circulate, and

discharge water upon each use is which of the following?

a. A fountain.

b. A packaged spa.

c. A therapeutic tub.

d. A hydromassage tub.

2. A permanently installed swimming pool shall no fewer than one 125 volt, 15-or

20-ampere receptacle on a general-purpose branch circuit shall be located at

what distance from the inside wall of the pool?

a. not less than 5 feet, not more than 20 feet

b. not less than 5 feet, not more than 10 feet

c. not less than 6 feet, not more than 20 feet

d. not less than 6 feet, not more than 10 feet

3. Lighting fixtures are permitted to be installed no less than which of the following

above the maximum water level of an outdoor pool?

a. 5 feet

b. 10 feet

c. 15 feet

d. 12 feet

4. Underground wiring is to be used to supply a lighting standard located 20 feet

from a swimming pool. What is the minimum horizontal clearance required

from the inside wall of the pool for this direct burial cable?

a. 5 feet

b. 10 feet

c. 15 feet

d. 20 feet


5. Unless listed and identified otherwise, an underwater lighting fixture installed in a

side wall of a pool shall be located a minimum of which of the following below

the normal water line?

a. 2 feet

b. 2 feet 6 inches

c. 1 foot 6 inches

d. 3 feet

6. A conductor used to connect two pieces of metal pool equipment is required to be

sized a minimum of # 8. This conductor is which of the following?

a. An equipment grounding conductor

b. A bonding conductor

c. A grounding electrode conductor.

d. A grounding conductor.

7. The minimum size of an equipment grounding conductor permitted to ground a wet

niche lighting fixture is:

a. # 12 insulated copper conductor

b. # 12 bare copper conductor

c. # 14 insulated copper conductor

d. # 14 insulated copper conductor

8. A panelboard at a swimming pool not part of the service equipment shall have an

equipment grounding conductor installed between its grounding terminal and the

grounding terminal of the service equipment, sized according to Table 250-95, but

not smaller than which of the following?

a. # 6 copper conductor

b. # 8 copper conductor

c. # 10 copper conductor

d. # 12 copper conductor

9. Receptacles located indoors where a spa or hot tub is installed shall be at least

which of the following distance from the inside walls of the spa or hot tub?

a. 20 feet

b. 15 feet

c. 6 feet

d. 10 feet


10. Lighting fixtures or lighting outlets that are located near a spa or hot tub located

inside and within five feet from the inside walls of the spa or hot tub and

protected by a ground-fault circuit-interrupter shall be what minimum height

above the maximum water level?

a. 8 feet

b. 7 feet 6 inches

c. 10 feet

d. not allowed

11. Each maintenance disconnecting means for pool equipment shall be


a. readily accessible

b. located at least 5 ft from wall of pool unless separated by barrier

c. either a or b

d. both a and b

12. Any wiring method for a pool associated pump motor shall include an

equipment grounding conductor which is?

a. insulated

b. not smaller than a # 14

c. uninsulated

d. directly connected to a grounding electrode

13. Where reinforcing steel of the pool shell is encapsulated with a nonconductive

compound, which of the following statements describes the required grid?

a. a minimum #8 solid copper conductor following the contour of the

pool

b. be arranged in 12 in. by 12 in. grid pattern

c. be secured within or under the pool no more than 6 in. from the pool

shell

d. all of the above

14. All 15- or 20-ampere, single-phase 125-volt through 250-volt receptacles located

within which of the following distances of a fountain edge shall be provided with GFCI protection.

a. 2 feet

b. 4 feet

c. 10 feet

d. 20 feet


15. Which of the following statements is true concerning outlets supplying pool pump

motors?

a. cord and plug connected motors shall be GFCI protected

b. direct connected motor shall not require GFCI protection

c. both cord and plug as well as direct connected motors shall have GFCI

protection

d. GFCI protection is not required for residential pools



ARTICLE 680

LEVEL I

ANSWER KEY

1. d. hydromassage tubs 680.2

2. c. not less than 6 feet, not more than 20 feet 680.22(A)(1)

3. d. 12 feet 680.22(B)(1)

4. a. 5 feet 680.10

5. c. (18 inches) 1 foot 6 inches 680.23(A)(5)

6. b, a bonding conductor 680.26(B)

7. a. #12 insulated copper conductor 680.23(F)(2)

8. d. # 12 copper conductor 680.25(B)(1)

9. c. 6 feet 680.43(A)(1)

10. b. 7 feet and 6 inches 680.43(B)(1)(b)

11. d. both a and b 680.12

12. a. insulated 680.21

13. d. all of the above 680.26(B) (1)(a)

14. d. 20 680.58

15. c. both cord and plug as well as direct connected 680.22(A)(2)(3)


SOLAR PHOTOVOLTAIC SYSTEMS

ARTICLE 690

LEVEL I

OBJECTIVE:

At the conclusion of this lesson each student should know about alternate sources of

power to power companies and some of the rules in installing these types of systems.

MATERIALS NEEDED:

Pictures from a local source of certain types of solar systems. Wiring

schematics showing how this system generates power.

INTRODUCTION:

When talking about photovoltaic systems let us first look at what it means. The definition

is: The total components and subsystems which in combination convert solar energy into

electrical energy suitable for connection to a utilization load. This means this is electrical

power for a load or loads in either conjunction with a local utility or totally on its own. In

this Article we will cover regulations we need to be looking for in these types of

installations.


Have the students read the definitions then go over certain key definitions such as:

Panel, Module, Power Source, Source Circuit, and Solar Cell (690.2). Where other

articles differ from this Article, Article 690 shall apply. (690.3).

Explain 690.1.

Photovoltaic system conductors shall be kept separate from all other raceways, cable

trays, cables, boxes, and anything similar containing branch circuits of other systems. The

grounded conductor shall be so installed at the panel or module so as to assure that the

removal would not interrupt the circuit. [690.31(B)]

In DC circuits the voltage considered shall be the rated open-circuit voltage. Source and

output circuits which do not included lampholders, fixtures, or receptacles shall be

permitted up to 600 volts. If over 150 volts to ground at a single family or two family

dwelling the output and source circuits shall be inaccessible to other than qualified

persons while energized. [690.7 (A, C, & D)]

Ampacity of conductors and overcurrent devices shall be based on 125% of the

current ratings of source circuits, output circuits and conditioning unit output

circuits. [690.8(B)(1)]


Circuits and equipment shall be protected according to Article 240. Power

transformers shall be protected according to Article 450. Overcurrent devices

shall be accessible but not required to be readily accessible. (690.9)

(D)Disconnecting shall means be provided to disconnect all conductors.

(690.13)

All equipment shall have disconnecting means. If equipment is energized from

more than one source all disconnects shall be grouped. (690.15)

Where fuses are separate from the disconnecting means a disconnect shall be

provided to disconnect the fuse, if energized from both directions and accessible

to other than qualified persons. Source circuit fuses shall be disconnected

separately from other circuit fuses. (690.16)

A switch or circuit breaker used as a disconnecting means shall:

1. Be located readily accessible

2. Be externally operable without exposing operator to live parts

3. Be indicating whether open or closed

4. Have ratings not less than the load served

When the DC circuit switch is designed so it cannot be opened under load the

disconnect can be lower than the load rating. (690.17) Means shall be provided to

disable an array or portions of an array. (690.18)

Connectors intended to be concealed shall be listed and meet the following:

(690.33)

a. Must be polarized and not interchangeable with receptacles of other circuits b

Guarded against accidental contact

c. Be latching or locking type

d. Grounding contact must be the first to make contact and the last to break

contact

e. Must be capable of interrupting circuit without hazard to operator

For a photovoltaic power source, one conductor of a 2-wire system rated over 50

volts and a neutral conductor of a 3-wire system shall be solidly grounded.

(690.41) The DC circuit shall be grounded at any point on the output circuit.

(690.42)

Where the power source short-circuit current is less than twice the current rating of

the overcurrent device or where overcurrent devices are not required according to

690.9(A) the grounding conductor shall be no smaller than the circuit conductors.

All others to be sized according to 250.134. (690.43)


All metal parts of equipment and conductor enclosures shall be bonded to the DC

circuit grounding electrode. Where more than one electrode is installed and they

are all bonded together it shall meet this requirement. (690.47)

Modules shall be marked with (1) open-circuit voltage, (2) operative voltage, (3)

maximum voltage, (4) operating current, (5) short circuit current, and (6)

maximum power. (690.51)

Power source must be marked with (1) operating current, (2) operating voltage,

(3) open-circuit voltage, (4) short-circuit current. (690.53)

If a power-conditioning unit is interactive with other systems it shall

automatically disconnect the ungrounded conductors in such other systems upon

loss of voltage and shall not be reconnected until voltage is restored. (690.61)

The maximum load connected between the neutral and any one ungrounded

conductor of single-phase or 3 phase circuits shall not exceed the ampacity of the

neutral conductor. (690.63)

Output of single-phase power conditioning units must not be derived from a delta-

connected transformer. Three phase power conditioning units shall automatically

disconnect all conductors when any one is lost. [605.64]

Output power productive source shall be permitted to be connected as follows:

(705.12)

1. On the supply side of service disconnecting means

2. On the load side of service disconnecting means if the following conditions are

met:

a. Each source interconnection shall be made as a dedicated circuit

b. Ampere rating of overcurrent devices shall not exceed rating of busbar.

(Can go up to 120% in a dwelling.)

c. Line side of GFI

d. Equipment containing overcurrent devices supplying power to busbars

shall be marked to indicate the presence of all sources.

Storage batteries must meet requirements of Article 480. If used in dwelling units

must operate at less than 50 volts, and be insulated to guard against accidental

contact. [690.71(B)(1)(2)]

APPLICATION:






ARTICLE 690

LEVEL I

WORKSHEET

1. Live parts of DC output circuits connected at a single family

dwelling rated at which of the following shall be accessible

only to qualified persons?

a. Under 150 volts ground

b. Over 150 volts ground

c. Over 150 volts line to line

d. Under 150 volts line to line

2. A switch or circuit breaker used as a disconnect shall:

a. Be located readily accessible

b. Accessible to qualified persons

c. Not required to be accessible

d. Located as to owner specifications

3. Wiring systems shall be permitted to be:

a. Rigid metal conduit

b. NM cable

c. AC cable

d. Any of the above

4. Lead-acid storage batteries for dwellings shall have no more than which of the following number of 2-volt cells connected in series

(48-volts nominal).

a. 12

b. 16

c. 20

d. 24


5. Where the removal of equipment disconnects between the

bonding connection between the grounding electrode conductor

and exposed conducting surfaces in the photovoltaic source or

output circuit equipment which of the following is required?

a. A bonding jumper shall be installed while the equipment is removed.

b. The area must be roped off in a manner that no one may enter.

c. The power company must be notified.

d. A sign must be placed in this area specifying exactly what has been

done and how long the jumper will not be in place.



ARTICLE 690

LEVEL I

ANSWER KEY

1. b, Over 150 volts ground 690.7(D)

2. a, Be located readily accessible 690.13 (A)

3. d, Any of the above 690.31

4. d, 24 690.71(B)(1)

5. a, a bonding jumper shall be installed. 690.48


ARTICLE 702

OPTIONAL STANDBY SYSTEMS

ARTICLE 702

LEVEL I

OBJECTIVE:

To inform the student that the provisions of this article apply to the installation

and operation of optional standby systems.

The systems covered by this article consist of those that are permanently installed

in their entirety, including prime movers, and those that are arranged for a

connection to a premises wiring system from a portable alternate power supply.

MATERIALS NEEDED:

Provide an example of an Optional Standby Generator (Photo, slide or overhead if

available)

INTRODUCTION:

Inform the student that this system is intended to supply power to public or

private facilities or property where life safety does not depend on the performance

of the system. Optional standby systems are intended to supply on-site generated

power to selected loads either automatically or manually. This system is often

used when situations occur that make it necessary for owners to perform

equipment maintenance or when breakdowns occur or when there is an extended

power outage. In such instances, a portable generator can be brought to a facility

and connected to the existing distribution system. The supervision by qualified

personnel is critical to ensuring that a dangerous backfeed condition is not created

by connecting the generator to the system without the benefit of transfer

equipment.


Explain that optional standby systems are typically installed to provide an

alternate source of electric power for such facilities as industrial and commercial

buildings, farms, and residences and to serve loads such as heating and

refrigeration systems, data processing and communications systems, and

industrial processes that, when stopped during any power outage, could cause

discomfort, serious interruption of the process, damage to the product or process,

or the like.


APPLICATION:






ARTICLE 702

WORKSHEET

LEVEL I

1. Where manual transfer equipment is used with adequate capacity and rating for

all of the equipment to be operated at one time, the user of the optional standby

system shall be permitted to do which of the following?

a. Select the load connected to the system.

b. Select the connection point to the system.

c. Select the grounded conductor location.

d. Select the optional fusing connection.

2. Audible and visual signal devices shall be provided, where practicable, for which

of the following purposes?

I. To indicate that the optional standby system is carrying load.

II. To indicate the derangement of the optional standby source.

a . I only

b. II only

c. Neither I or II

d . Both I and II

3. Where a portable optional standby source is used as a nonseparately derived

system, the equipment grounding conductor shall be bonded to which of the

following?

a. A grounded conductor

b. The grounding electrode conductor

c. The earth

d. The system grounding electrode



ARTICLE 702

LEVEL I

ANSWER KEY

1. a, Select the load connected to the system 702.4(B) (1)

2. d, Both I and II 702.6 (1) and (2)

3. d, The system grounding electrode 702.11(B)


INTERCONNECTED ELECTRIC POWER PRODUCTION SOURCES

ARTICLE 705

LEVEL I

OBJECTIVE:

Each student should be acquainted with the requirements for interconnected electric power

production sources and their installation(s).

INTRODUCTION:

This article applies to interconnected electric power production sources. This article covers

the installation of one or more electric power production sources operating in parallel.


Cover the definitions outlined in 705.2. Explain in detail that other articles; such as 445

Generators, 690 Solar Photovoltaic (PV) Systems, and 692 Fuel Cell Systems, apply to the

use of this article.

Cover in detail 705.12 Point of connection, inverters and overcurrent.

705.20 through 705.22 for disconnecting means of sources and equipment and their

prospective locations.

705.30 Overcurrent protection of solar photovoltaic systems, transformers, fuel cell

systems, utility-interactive inverters, and generators.

APPLICATION:



If time will allow, correct the worksheets and discuss the results. Ensure the students

understand Article 705.


INTERCONNECTED ELECTRIC POWER PRODUCTION SOURCES

ARTICLE 705

LEVEL I

WORK SHEET

1. The output of a generator or other electric power production source operating in

parallel with an electrical supply system shall be compatible with the;

a. voltage b. wave shape

c. frequency d. all the above


INTERCONNECTED ELECTRIC POWER PRODUCTION

SOURCES

ARTICLE 705

LEVEL I

ANSWER SHEET

1. d, all the above 705.14


COMMUNICATION CIRCUITS

ARTICLE 800

LEVEL I

OBJECTIVE:

This article covers voice, audio, video, data, interactive services, telephone, telegraph

(except radio), outside wiring for fire alarm and burglar alarm, and similar central station

systems; and telephone systems not connected to a central station system but using similar

types of equipment, methods of installation, and maintenance. Cover Article 810 for

Radio and Television Equipment, Article 820 for Community Antenna Television and

Radio Distribution Systems, and Article 830 for Network-Powered Broadband

Communications Systems.

MATERIALS NEEDED:

Provide examples of communications cables, (CATV, telephone wire, RG-8, etc.),

pictures and or plans of towers, and communications wiring diagrams.

INTRODUCTION:

When talking about communications systems, let us first look at what it means. The

definition is: The electronic equipment that performs the telecommunications operations

for the transmission of audio, video, and data, and includes power equipment (e.g., dc

converters, inverters and batteries) and technical support equipment (e.g., computers).


Have the students read the definitions then go over certain key definitions such as:

Abandoned Communications Cable, Cable, Point of Entrance, Premises, and Wire. Cover

articles 800.100, 800.154 (including the tables), and additional Sections in

communications such as article 810, article 820, and article 830. Be sure to cover in detail

the bonding and grounding of communication systems.

APPLICATION:





COMMUNICATIONS CIRCUITS

ARTICLE 800

LEVEL I

WORKSHEETS

1. Communication circuit cables installed in ducts, plenums and other spaces

used for environmental air can be which of the following?

a. CMP

b. C MR

c. CMG

d. CMX

2. A bonding jumper not smaller than which of the following (or equivalent) shall

be connected between the communications grounding electrode and power

grounding electrode system at the building or structure served where separate

electrodes are used?

a. # 4 AWG

b. # 3 AWG

c. # 8 AWG

d. # 6 AWG

3. Where practicable, a separation of at least which of the following shall be

maintained between communications wires and cables on buildings and

lightning conductors?

a. 10 feet

b. 8 feet

c. 5 feet

d. 6 feet

4. Cable and primary protector grounding conductors shall be insulated

and shall be listed as suitable for the purpose. The grounding conductor shall

be copper or other corrosion-resistant conductive material, stranded or solid

and the grounding conductor shall not be smaller than which of the

following?

a. # 14 AWG.

b. # 6 AWG.

c. # 4 AWG

d. # 8 AWG


5. Communications wires and cables from the protector to the equipment or,

where no protector is required, communications wires and cables attached

to the outside or inside of the building shall be permitted in the same raceway or

enclosure with cables of any of the following except?

a. Class 2 and Class 3 remote-control, signaling, and power-limited

circuits.

b. Power-limited fire alarm systems.

c. Nonconductive and conductive optical fiber cables.

d. High-power network-powered broadband communications circuits.


COMMUNICATIONS CIRCUITS

ARTICLE 800

LEVEL I

ANSWER SHEET

1. a, CMP 800.154 (a)

2. d, # 6 AWG 800.100(D)

3. d, 6 feet 800.53

4. a, # 14 AWG 800.100(A)(3)

5. d, High-power network is not listed 800.133(A)(1)(a)(b)

2014 ELECTRICAL INSPECTOR INSTRUCTORS' MANUAL LEVEL I

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Transcript of 2014 ELECTRICAL INSPECTOR INSTRUCTORS' MANUAL LEVEL I