Junction box questions


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Old 05-07-15, 07:00 PM
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Junction box questions

Hello! In my attic, I have a bunch of older NM cable that was spliced together not in junction boxes. I would like to tidy it up and put those junctions in boxes. Since it may be NM w/o ground, I wouldn't have an easy way to ground a metal junction box. Is it permissible by code to use a plastic junction box in the attic space?

I'm also wondering about using a 1-gang box to make a connection to extend some NM-B elsewhere. It currently runs to a poorly located outlet. I know j-boxes have to remain accessible so I can't use a traditional square box behind the wall there. I would like to use the existing 1-gang box, remove the receptacle, and just make the connection in there. Then, I could cover it up with a blank plate to leave the junction accessible. OK by code?

Thanks all!
 
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Old 05-07-15, 07:07 PM
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Is it permissible by code to use a plastic junction box in the attic space
Yes.
I'm also wondering about using a 1-gang box to make a connection to extend some NM-B elsewhere.
You previously wrote the NM has no ground. An ungrounded cable is grandfathered but any new cable must meet current code. Code requires a ground so if no ground the cable can't be extended.
 
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Old 05-07-15, 07:10 PM
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Sorry, I should have clarified. The NM-B that I would be extending is a different circuit than the older ungrounded NM in the attic. The one that I would extend is grounded.
 
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Old 05-07-15, 07:25 PM
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Then so long as the splice remains accessible and removing the receptacle doesn't violate the 6 foot rule* for receptacle spacing it should be okay.

* ...no point along the wall space is more than 6 feet, measured horizontally along the floor line, from a receptacle outlet
 
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Old 05-09-15, 04:38 PM
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And a follow-up question along the same lines. This pertains to yet another circuit elsewhere in the house. Someone previously did basically the same thing I was thinking of doing -- a plastic single gang box, nailed to the ceiling in the basement, as a junction box. My three questions on this box:

There are two different vintages of NM in the box. One is a black, fabric-sheathed NM, with no visible markings. Another is plastic-sheathed, and clearly marked NM-B. I opened up the box. Both have grounds. It looks legit to me, hots to hots, neutrals to neutrals, grounds to grounds. New NM-B from the panel goes in, connects to old, and old goes out to the rest of the house. Nothing fancy. Any problems with this?

On the same junction box, the box itself is plastic. However, a metal cover plate was installed on it. My gut says this is improper since the box is plastic and can't be grounded, but the cover could still potentially become energized. Does the cover plate need to be (or at least should it be) replaced with a plastic cover?

Also, the plastic box is cracked. Does it need to be replaced?

Thanks a bunch.
 
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Old 05-09-15, 05:23 PM
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There are two different vintages of NM in the box. One is a black, fabric-sheathed NM, with no visible markings. Another is plastic-sheathed, and clearly marked NM-B.... Both have grounds... hots to hots, neutrals to neutrals, grounds to grounds
That is okay.
Also, the plastic box is cracked.
I,d use a metal octagon and metal cover plate. Pigtail the grounds to the box.
he box itself is plastic. However, a metal cover plate was installed on it
If the box wasn't cracked I'd say replace with a plastic cover plate.

Opinion: Metal octagon or square boxes are better than switch boxes for junction boxes.
 
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Old 05-09-15, 05:26 PM
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The wiring of the box sounds fine. The metal cover should be change to plastic for the reasons you mentioned, this is a common error people do. If the box is just cracked, but still seams solid, I would leave it. If it appears the box's structural integrity has been compromised due to the crack, you might want to replace it.
 
 

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