UF, THHN, or is NM ok?

[tmelo49]

After busting my rear in the hot sun yesterday pulling 12/2 NM romex from my attic to an outdoor 1/2" PVC conduit. I've come to learn that NM can never be run outside. I hope someone can help me out with this one. Can I leave it as is? Should I rerun UF (which may be too tight in the 1/2" conduit), and connect it to the NM in the attic via a junction box. OR should I run THHN through the 1/2" conduit and connect that to the NM in the attic via a junction box?

HELP!

[Rewired]

Don't quote me on this but (at least here anyways) regular NM cable can be run outside as long as its in a conduit, and the conduit is not buried in the ground at any point. What you have there I would leave as long as anywhere outside you do NOT have the NM cable exposed at any point.

A.D

[kactuskid]

NM should not be installed in any conduit, you should run the THHN in the conduit and go with a junction box inside to make the splice between NM and it. Outside you need to bury the pvc conduit at minimum 18 inches.

[Rewired]

Damn! I wish the code was STANDARD and didn't vary between U.S.A and Canada!!!

[HayZee518]

PVC should be buried a minimum of 18 inches in the ground and surrounded by sand below and above it. Wires for the inside should be THHN, THWN as both are sunlight and water resistant. UF can be run inside the conduit but just to afford exposed mechanical protection - the rest of it can be buried. DO NOT run NM inside the conduit, there's no way the heat generated in the conductors can escape and they might melt together.

[Rewired]

THHN / THWN is "Sunlight resistant"????????
Wow, like I have mentioned before it would be nice if code was standardized EVERYWHERE, because up here in Canada, THHN / THWN (we call it T-90 or TWN-75), it can NOT be exposed to sunlight no where no how!!! Apparently it will "break down".. Its too bad though, it would be nice to be able to use THHN / THWN for overhead services,(out the top of the mast) instead of the good old TW-75 and RW-90 we have to use What a pain it is to work with!

[HayZee518]

In the NEC there's a section that describes all the abbreviations of wires. THHN, THWN are listed together it is 90 degrees C, nylon covered thermoplastic, stranded. Overhead service cable is also a thermoplastic that goes by the designator of THW, with a bare messenger cable or ground - also called tri-plex, type ACSR. Steel Re-inforced aluminum. (Tom)