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Electrical Wiring FAQ (Part 2 of 2)
Section - Should I use plastic or metal boxes?

( Part1 - Part2 - Single Page )
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Top Document: Electrical Wiring FAQ (Part 2 of 2)
Previous Document: What is Romex/NM/NMD? What is BX? When should I use each?
Next Document: Junction box positioning?
See reader questions & answers on this topic! - Help others by sharing your knowledge

	The NEC permits use of plastic boxes with non-metallic cable
	only.  The reasoning is simple -- with armored cable, the box
	itself provides ground conductor continuity.  U.S. plastic
	boxes don't use metal cable clamps.

	The CEC is slightly different.  The CEC never permits cable
	armor as a grounding conductor.  However, you must still
	provide ground continuity for metallic sheath.  The CEC also
	requires grounding of any metal cable clamps on plastic boxes.

	The advantage of plastic boxes is comparatively minor even for
	non-metallic sheathed cable -- you can avoid making one ground
	connection and they sometimes cost a little less.  On the other
	hand, plastic boxes are more vulnerable to impacts.  For
	exposed or shop wiring, metal boxes are probably better.

	Metal receptacle covers must be grounded, even on plastic
	boxes.  This may be achieved by use of a switch with ground
	connection.

User Contributions:

1
Dev
In a fire protection circuit, circuts are shown witha no example 6,8,4etc. what it mean?these circuits are connected between smode detector,junction box etc
2
kevin
My daughter dropped a small necklace behind her dresser. The necklace crossed a plug terminal and shorted the receptacle.
I bought a new receptacle and installed the same. I still have no power I suspect there could be a bigger problem,this is aluminum wiring.
I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit.
3
dennis
Regarding new construction wiring and running 12/2 and 14/3 wire in the same box.

I have multiple switches to lights. Ran 12/2 and 14/3 into switch box and inspector wrote correction needed.

What should I have done instead?

thank you
dennis
4
Robert
Does a grounding electrode facilitate the operation of a OCPD, to clear a ground fault ?
5
@dennis
Assuming you are installing two switches in a two switch box, you probably should have used 14/2 and 14/3 instead of replacing 14/2 with 12/2. If you are only installing one switch in a one switch box, you should only have one cable in the box.
6
P k
I prefer to use nothing smaller than12 awg /the smallest sized wire on a circuit determines the allowable ampacity
Ex: 15 amp-14awg. 12awg-20amp only rule for thumb other factors such as continuous load,heating and others if you do not know the safe NEC rules then please call a qualified journeyman Electrician better be safe

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Top Document: Electrical Wiring FAQ (Part 2 of 2)
Previous Document: What is Romex/NM/NMD? What is BX? When should I use each?
Next Document: Junction box positioning?

Part1 - Part2 - Single Page

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Last Update March 27 2014 @ 02:11 PM