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phareous 07-09-2013 03:27 PM

Can I run THWN inside an aluminum post?
I'd like to run THWN inside aluminum posts on my screen porch and put an outlet on the outside of the post. Is there anything that would prevent me from doing this as far as code? It seems like it isn't much different than doing conduit or wire molding (other than the fact that is load-bearing)

k_buz 07-09-2013 03:35 PM

Nope, not an approved wiring method.

phareous 07-09-2013 03:54 PM


Originally Posted by k_buz (Post 1213778)
Nope, not an approved wiring method.

Ok how about if I do UF inside the column?

Philly Master 07-09-2013 05:29 PM

Yes that would be fine...UF

bobelectric 07-09-2013 06:07 PM


Originally Posted by k_buz (Post 1213778)
Nope, not an approved wiring method.

That's how we wire roadway lights.

k_buz 07-09-2013 06:52 PM

Apples and oranges

mpoulton 07-10-2013 02:49 PM


Originally Posted by bobelectric (Post 1213852)
That's how we wire roadway lights.

The light pole is part of the UL listed fixture assembly, so it's intended to be used that way. The posts on this patio are not. UF cable is the easiest code-compliant solution I think.

kbsparky 07-10-2013 07:23 PM

Some aluminum porch manufacturers offer UL listed wireway channels as part of their support posts.

IF yours is one such listed post, then you can install THHN/THWN wiring without any further cabling or raceways.

phareous 07-10-2013 10:54 PM

So I need some advice. I was going to use metal receptacle boxes that have 1/2" threaded hole in the back. I can't find anything to secure the wire in the box. I need to have two 12-2 UF in there. The UF connector I found would only support one cable. I found a pvc male adapter that would fit but the outside is too big to go into the hole I drilled and it wouldn't really secure the cable anyway (only keep it from getting snagged on the drilled hole). I tried a plastic nm ring but it wouldn't fit. I think maybe I could use a threaded clamp of some sort if I could find one. Another issue with the boxes I have is they have metal ribs on the back (I assume to dig into wood)..but I may need to grind that off to sit flush with the pole.

What kind of boxes and clamps would you use if you did this?

phareous 07-10-2013 11:16 PM

I'm thinking maybe I could use rubber grommets in the hole I cut? I would still need to clamp the wire in the box per code right?

mm11 07-11-2013 06:24 AM

Use a NM connector, listed for 2 cables. You'll probably need to ream the hole already cut to accept the connector, but the box will definitely cover the larger hole.

J. V. 07-11-2013 11:14 AM

Personally, I would use a chase nipple instead of a connector. Not exactly compliant, but what i would do none the less.

phareous 07-13-2013 11:57 PM

So what I did was get the plastic bushing designed for metal studs. I put those in the holes in the posts to protect the wire. Then I screwed the boxes to the posts and put the nm connector on there backwards (with it coming into the box) and used needlenose pliars to screw down the connector screws. I could not do it the other way as the connector would not go through the post hole without making the holes twice as big. Inspector comes Monday...I guess I'll soon know if it was ok or not

mpoulton 07-14-2013 01:07 AM

That's definitely not a code compliant way of using the connectors, but an inspector might pass it. A snap-in plastic connector would probably fit the right way.

phareous 07-14-2013 07:37 AM

I can't find a plastic snap in connector that would fIt a 1/2 threaded hole

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