DAY 4 CHAPTER 3 CONDUCTOR SIZES,TYPES, ETC.. Continuous Load. A load where the maximum current is...
-
Upload
edwin-walters -
Category
Documents
-
view
214 -
download
0
Transcript of DAY 4 CHAPTER 3 CONDUCTOR SIZES,TYPES, ETC.. Continuous Load. A load where the maximum current is...
DAY 4 CHAPTER 3 CONDUCTOR SIZES,TYPES, ETC.
Continuous Load. A load where the maximum current is expected to continue for 3 hours or more. Continuous loads shall not exceed 80% of the rating of the Branch circuit
CIRCUIT BREAKERS ARE THE FINAL OVERCURRENT PROTECTION DEVICE
Branch Circuit. The circuit conductors between the finalovercurrent device protecting the circuit and the outlet(s).BRANCH CIRCUIT HAS 3 PARTS 1. CIRCUIT BREAKER 2. CONDUCTOR 3. DEVICES
THERE ARE 4 TYPES OF BRANCH CIRCUITS.1. SMALL APPLIANCE. 2. INDIVIDUAL 3. GENERAL PURPOSE 4. MULI-WIRE.
Branch Circuit, Individual. A branch circuit that supplies only one utilization equipment.
Branch Circuit, Appliance. A branch circuit that supplies energy to one or more outlets to which appliances are to be connected
Branch Circuit, General-Purpose. A branch circuit that supplies two or more receptacles or outlets for lighting and appliances.
Branch Circuit, Multiwire. A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.
TYPE NM CABLE MUST HAVE A BENDING RADIUS AT LEAST 5 TIMES THE DIAMETER OF THE CABLE.334.24
CONDUCTOR SIZE COLOR 14 AWG WHITE 12 AWG YELLOW 10 AWG ORANGE 8 AWG BLACK
COLOR CODE FOR NM-B CABLE 6-32: FIXING RECEPTELES TO DEVICE BOXES AND FACE PLATES ALSO FOR PLASTIC BOXES.
8-32: ATTACHING MUD RINGS TO BOXES
10-32: CEILING FAN BOXES,GROUND SCREWS
MAXIMUM OVERCURRENT FOR14AGW = 15AMPS12AGW = 20AMPS10AWG = 30AMPS
INDIVIDUAL BRANCH CIRCUIT HAS 1 HOT,1 NETURALMULTI-WIRE CIRCUITS HAVE 2 HOTS, 1 NETURAL
COLOR CODEWHITE IS RESERVED FOR NEUTRAL(GROUNDED CONDUCTOR)GREEN IS RESERVED FOR (GROUNDING CONDUCTOR), CAN ALSO BE BARE.BLACK, RED, ETC ARE HOT.(UNGROUNDED CONDUCTOR)
3 METALS ARE ALLOWED FOR CONDUCTORS 1.COPPER 2.ALUMINUM 3 COPPER CLAD ALUMINUM
FOR A 15A CIRCUIT.
FOR A 20A CIRCUIT.
Branch Circuit. The circuit conductors between the finalovercurrent device protecting the circuit and the outlet(s).
BRANCH CIRCUIT HAS 3 PARTS 1. CIRCUIT BREAKER 2. CONDUCTOR 3. DEVICES
Feeder. All circuit conductors between the service equipment,the source of a separately derived system, or otherpower supply source and the final branch-circuit overcurrentdevice.
Continuous Load. A load where the maximum current is expected to continue for 3 hours or more. Continuous loads shall not exceed 80% of the rating of theBranch circuit
Some loads in homes are continuous, such as electric water heaters, central electricheating, A/C. For these loads branch circuit rating, conductors, and the overcurrentdevices can’t be less then125% of the load.
Example: A/C with a name plate rating of 40amps, requires conductors and acircuit breaker with a rating of
ampsampsof
assametheisthis
ampsamps
4050%80
5025.140
CIRCUIT BREAKERS ARE THE FINAL OVERCURRENT PROTECTION DEVICE
THERE ARE 4 TYPES OF BRANCH CIRCUITS.
1. SMALL APPLIANCE.2. INDIVIDUAL3. GENERAL PURPOSE4. MULI-WIRE.
Branch Circuit, Appliance. A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance.
Branch Circuit, Individual. A branch circuit that suppliesonly one utilization equipment.
Branch Circuit, General-Purpose. A branch circuit thatsupplies two or more receptacles or outlets for lighting andappliances.
SUPPLIES ONLY ONE PIECE OF EQUIPMENT
Branch Circuit, Multiwire. A branch circuit that consistsof two or more ungrounded conductors that have a voltagebetween them, and a grounded conductor that has equalvoltage between it and each ungrounded conductor of thecircuit and that is connected to the neutral or groundedconductor of the system.
MAXIMUM OVERCURRENT FOR14AGW = 15AMPS12AGW = 20AMPS10AWG = 30AMPS
INDIVIDUAL BRANCH CIRCUIT HAS 1 HOT,1 NETURAL
MULTI-WIRE CIRCUITS HAVE 2 HOTS, 1 NETURAL
COLOR CODEWHITE IS RESERVED FOR NEUTRAL(GROUNDED CONDUCTOR)GREEN IS RESERVED FOR (GROUNDING CONDUCTOR), CAN ALSO BE BARE.BLACK, RED, ETC ARE HOT.(UNGROUNDED CONDUCTOR)
3 METALS ARE ALLOWED FOR CONDUCTORS 1.COPPER 2.ALUMINUM 3 COPPER CLAD ALUMINUM
200.7grounded circuit conductor, (A)(1) A conductor with continuous white or gray covering(2) A conductor with three continuous white stripes onother than green insulation(3) A marking of white or gray color at the termination
250.119 Identification of Equipment Grounding Conductors. (B)shall be permitted to be bare, covered, or insulated. Individually covered or insulated equipment grounding conductors shall have a continuous outer finish that is either green or green with one or moreyellow stripes
Ungrounded conductor (hot) can be any colorOther than white, gray, green, or green withYellow strips. (C)
AMPACITY: CURRENT CARRYING CAPACITY OF A CONDUCTOR.
THE ALLOWED AMPACITY OF CONDUCTORS IN RESIDENCES IS FOUND IN TABLE 310.16. THESE AMPACITIES ARE SUBJECT TO CORRECTIONFACTORS FOR HIGH AMBIENT TEMPERATURES. THESE ARE FOUND ATTHE BOTTOM OF T 310.16. p70-148
T310.16 IS FOR THREE OR LESS CONDUCTORS IN A RACEWAY OR CABLE.
EXAMPLE: A 12AWG THHN COPPER CONDUCTOR AT 90°CIS RATED AT 30AMPS. IF THE AMBIENT TEMP. IS 56°C THECORRECTION FACTOR IS 0.71. USING THIS GIVES;
30AMPSX0.71=21.3AMPS, THIS IS THE DERATED USABLE AMPERAGE FOR THIS 12AWG CONDUCTOR.
IF THERE ARE MORE THEN 3 CONDUCTORS PRESENT A ADDITIONALCORRECTION FACTOR MUST BE APPILED AND IS FOUND IN TABLE310.15(B)(2)(a) p70-146
(2)
GIVEN THE SAME WIRE GAUGE SIZE, THE HIGHER ITS INSULATOR TEMPERATURE RATING IS, THE GREATER ITS AMPACITY WILL BE.
EXAMPLE: WHAT IS THE NUMBER OF RECEPTACLES ALLOWED FOR 15A AND 20A BRANCH CIRCUITS
HOW MUCH POWER CAN BE USED BY A 15A CIRCUIT?USING THE POWER EQUATION;
WP
VAP
IVP
1800
12015
APPLYING THE 80% AMPACITY CORRECTION FACTOR GIVES;
WW 144080.1800 WE ARE ALLOWED 180VA PER RECEPTACLE FROM 220.14(I) p70-59USING DAVID’S RULE OF THUMB TO FIND # OF RECEPTACLES PER BRANCH CIRCUIT;
SRECEPTACLENUMBER VAW
SRECEPTACLE 81801440
FOR A 15A CIRCUIT.
HOW MUCH POWER CAN BE USED BY A 20A CIRCUIT?USING THE POWER EQUATION;
WP
VAP
IVP
2400
12020
USING 80% AMPACITY CORRECTION FACTOR GIVES;
WW 192080.2400 GIVEN THAT 180VA PER RECEPTACLE FROM 220.14USING DAVID’S RULE OF THUMB TO FIND # OF RECEPTACLES PER BRANCH CIRCUIT;
SRECEPTACLENUMBER VAW
SRECEPTACLE 101801920
FOR A 20A CIRCUIT.
MAX. DISTANCE AROUND WALL CORNERS=12FT.
Fixed panels are counted as wall space Sliding panels are not wall space
One family Duplex
FISH TAPE(WIRE PULLERS) FOR PULLING WIRES THRU CONDUIT: COME IN LENGTHS FROM 25 TO100 FEET
VARIOUS LOOPS AVAILABLE AS FISH TAPE ENDS
WIRE LOOP AT END OF FISH TAPE
A NITROGEN POWERED GUN FOR PULLINGGUIDE ROPES THRU CONDUIT UP TO 100’
http://www.wikihow.com/Fish-Wires-Through-a-Conduit-or-PipeHow to Fish Wires Through a Conduit or Pipe