Chapter 10 – Electric Box Installation CHAPTER 6 BOXES.

Chapter 10 – Electric Box Installation

CHAPTER 6

BOXES


2

Selecting the Appropriate Electric Box Type

• Considerations when selecting an electrical device– Single-gang– Two-gang– Three-gang or more

• Information found on electrical plan


3

Selecting the Appropriate Electric Box Type

• Consider whether it will be used in new or old work.


4

USES PERMITTED

• Minimum depth 1/2 inch in depth• Used for luminaries must be rated for that

purpose• Luminaries that weigh more then 50 pounds

must be supported independently• Ceiling fans shall be installed with boxes rated

for that purpose• Must be accessible


5

BOX MOUNTING

• In non-combustibles materials boxes shall be mounted not more then 1/4 in from surface

• In combustible materials boxes must be mounted flush with wall surface

• Article 314.20• Gaps larger then 1/8 in around a box must be

repaired.


6

Installing Nonmetallic Device Boxes

• Most common method– nail them directly to a

wood framing member.


7

Installing ‘Old Work’ Boxes in Existing Walls and Ceilings

– Metal straps that spread open and do not allow the box to come back out of the hole.


8


• To install ‘old work’ boxes, cut a hole into the wall or ceiling at the location where you wish to mount the box.

• The plaster ears keep the boxes from going too far into the hole, but there has to be some other device that will keep the box from coming back out of the hole.


9


– Sheetrock grips that are tightened to hold the box firmly in the wall or ceiling.

– Madison Hold-Its (also known as Madison Straps or Madison Hangers), thin metal straps installed on each side of an ‘old work’ box to provide a secure attachment.


10

BOX PARTS

• knock outs

• fittings

• connector

• conduit bodies

• ground clip

• bushing

• box extension


11

BOX FILL• Article 314-16

• all conductors count toward fill allotment

• only fittings and clamps that are on the inside of box count toward fill allotment

• devices that have a mounting strap or A yoke count as two conductors

• all ground wires count as one conductor

• pig tails do not count


12

CONDUCTOR SIZE• No. 14............................... 2. cubic inches

• No. 12............................... 2.25 cubic inches

• No. 10............................... 2.5 cubic inches

• No. 8............................... 3. cubic inches

• No. 6............................... 5. cubic inches

Chapter 10 – Electric Box Installation CHAPTER 6 BOXES.

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Transcript of Chapter 10 – Electric Box Installation CHAPTER 6 BOXES.