While I know that this subject has been discussed before and many times people have not recommended putting romax in conduit; is it against code? When I ran power to my workshop from the meter box on the house the electrician had me put the 6/3 cable into a gray flex conduit for the entire run of 90 feet. If that was ok and the inspector never said a thing about it. Then why not put 12/2 or 14/2 in rigid conduit for short runs so it is not exposed to the elements.
Edited 6/29/2008 9:29 am ET by PD
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It can be done but the sizing and possible derating issues are considerations best left to some serious reading of code/guide books and even better a professional. Romex, is a brand of NM cable. The name has become the household equivalent like in ancient times Kelvinator and Fridge.
You can put NM in conduit to protect it from physical damage. This is detailed in section 334.15(B) of the NEC.
First ... I"m not an electrician ... but have done a bunch of wiring. I don't believe NM wire in conduit is a code issue ... but the guy did mention derating the capacity of the conduit.
Any wire 'exposed' must always be protected or suitable for exposure or direct burial, I believe.
I just strip off the jacket and paper after the clamp using it for drops.
Cable in conduit does not have to be derated just because it is cable in conduit.
Wiring does have to be derated is there are the equivalent of 4 or more equivalent current carrying conductors bunbled togehter for more than 24". That bundling canbe cables that are bundled together and/or conduit which keeps the wires together whether they are invidiudal wires and/or cables.
Non-metalic cable (NM aka Romex) can be run exposed, if it is run tight against the surface, except where exposed to PHYISCAL DAMAGE. Sch 80 PVC or metal conduit can be used for the protect.
You can use sch 40 PVC and the flex PVC can be WHERE IT IS NOT SUBJECT TO PHYISCAL DAMAGE.
What is subject to phyuisical damaged is undefined.
NM is only allowed to be installed in dry locals. That would exclude exterior applications.
I am not sure installing it in conducit on the exterior makes that a dry location or not. I know that underground conduit is treated as a wet area because of condensation.
For simple sleaving of a straight run, such as down a basement wall, the NM can be slipped inside the conduit.
But for general purpose use the conduit needs to be sized for pulling the cable it it. That requires treating the NM as a large single wire and upsizing a size or two.
It is not legal to strip the insulation from the NM and using just the wires. Although the wires have the same construction as THNN it is test or approved as such.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.