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Old 09-29-2008, 11:24 AM   #1
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Use of unsheathed Romex NM-B wires in conduit?


Quick question:

I need to drop three circuits down a concrete basement wall to two adjacent 4 x 4 receptacle boxes I'll be mounting on the wall. I want to protect the wires along the wall within one run of 3/4" EMT. Can I just bring the NM-B cables into a junction box mounted near the ceiling and strip off 4-5 feet of sheathing from these cables and drop the individual wires through the conduit to the boxes?

Fill restrictions prevent me from running the whole NM cables within the conduit. Basically, I want to know if I can avoid having to splice in actual THHN/THWN wire at the junction box for the drop through the conduit (the wires within the Romex cable are not marked as to their specifications). I'll use a separate insulated green ground wire through the conduit, so I can splice all the grounds together in the junction box and just run one ground wire to the boxes.

Thanks for your help.

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Old 09-29-2008, 11:52 AM   #2
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Use of unsheathed Romex NM-B wires in conduit?


Idividual wires in NM-B are not rated for conduit use.

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Old 09-29-2008, 12:00 PM   #3
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Use of unsheathed Romex NM-B wires in conduit?


Agreed. No can do.
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Old 09-29-2008, 12:10 PM   #4
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Use of unsheathed Romex NM-B wires in conduit?


Thanks. I'll be buying some THHN/THWN wires for the drop.
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Old 09-29-2008, 12:23 PM   #5
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Use of unsheathed Romex NM-B wires in conduit?


Conduit fill requirements do not apply to short lengths of conduit that are not emerging from grade and the conduit is only being used for physical protection. See note 2 chapter nine.
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Old 09-29-2008, 01:54 PM   #6
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Use of unsheathed Romex NM-B wires in conduit?


Thanks Stubbie. I guess I forgot about that note when I first read it a while back. So this means I can put a suitable cable clamp at the top of the conduit and run the 3 NM cables directly down to the outlet boxes. This will be so much easier. Thanks again.
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Old 09-29-2008, 02:09 PM   #7
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Use of unsheathed Romex NM-B wires in conduit?


Yep. alot of guys just put on a emt box connector and then thread on a plastic bushing to handle any abrasion issue where the cables enter emt. I actually think it is a code requirement to do so.


Two types I use


and
with this....
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Old 09-29-2008, 04:17 PM   #8
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Use of unsheathed Romex NM-B wires in conduit?


Quote:
Originally Posted by Stubbie View Post
Yep. alot of guys just put on a emt box connector and then thread on a plastic bushing to handle any abrasion issue where the cables enter emt. I actually think it is a code requirement to do so.


Two types I use


and
with this....
A bushing is a code requirement for protection of the wire. I use the cheapo plastic ones.

Sorry, I failed to thoroughly read the original post that said that this was a very short length of conduit indoors...My bad. Glad Stubbie got to you before you bought the THHN.
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Old 09-29-2008, 06:21 PM   #9
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Use of unsheathed Romex NM-B wires in conduit?


Quote:
Originally Posted by thekctermite View Post

Sorry, I failed to thoroughly read the original post that said that this was a very short length of conduit indoors...

Who cares if its a short run, you can still use NM in conduit as long as the fill requirement is met.


Never mind, I agree with Stubbie.

Last edited by chris75; 09-29-2008 at 06:56 PM.
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Old 09-29-2008, 06:47 PM   #10
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Use of unsheathed Romex NM-B wires in conduit?


I don't think you will fit 3 NM cables into a 3/4 conduit.
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Old 09-29-2008, 06:57 PM   #11
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Use of unsheathed Romex NM-B wires in conduit?


Quote:
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I don't think you will fit 3 NM cables into a 3/4 conduit.
Sure you will, 3/4 is huge.

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