DIY Home Improvement Forum banner

Can type nm-b wire be used outside in conduit?

1 reading
50K views 25 replies 12 participants last post by  RWolff  
#1 ·
Can type nm-b (14-3) romex wire be used outdoors if placed in conduit to add additional receptacles to the back of a house/
 
#4 ·
Conduit which is not subject to any weather would be OK, but very few outdoor locations fit that description. The bottom line is this: if you could use NM there without conduit, then you could sleeve it in conduit. If you can't use NM there without conduit due to weather exposure, then adding conduit doesn't get you anything. The inside of a conduit in a wet location is a wet location.
 
#8 ·
One thing over here it will be the same rules no NM cable on outdoor location as well only UF cable or THHN/THWN or SWA ( steel wire armoured cable ) is one of few most common allowed items we can use on outdoor useage over here in France.

Merci,
Marc
 
  • Like
Reactions: Kyle_in_rure
#17 ·
Most of the stuff posted on here, is thrown out with nothing written anywhere to back it up. Majority is from most of us doing this stuff over the years, and finding the best way to get the job done, so that it not only meets codes, but also so that when the next person comes along to do something with what you did, they are still able to complete the job, or fix the problem if one occurs, due to a bad outlet or switch.

Guessing you like bobelectric have not learned how to do this, when working on stuff. At times, you have to think outside the box as I stated before, to get the job done, while staying within the rules. But then again, guessing by your questioning my remark, along with bobelectrics, you both have never learned how to do stuff out of the box to get the job done, while following the rules.
 
#18 ·
:rolleyes:

Anyway...the fact is, you can run NM outside as long as it's a dry location (under a porch roof, for instance). Being outside does NOT automatically make it a wet location, being buried does, but not being outside. So, as long as it's a dry location, you can run NM cable for as long as you want...there is NO 8" limit.
 
#19 ·
What did I state about coming out of the boxes, and did you even read what I posted about the fact that it was just a statement, not a rule.

But I guess you are going to slam that like the fact, that most take this stuff way too serious, when we even state that you need to follow your local rules as to what they require when performing any type of work, whether it is electrical, hvac, plumbing, and that anything posted on these forums, is not code nor the rule of the land.
 
#21 ·
No you cannot run NM outside as far as you want to. It can only go as far as the box on the side of the house, and from there if you want to extend the outlet to say a lighting fixture out in the front yard, or a stub for a outlet, to connect lights on bushes, you either have to use conduit with THHN/THWN or UF from the junction box on the side of the house.

For what the OP asked about, was if it was okay to use NM inside conduit. They did not state how far they were going to run it inside the conduit, or how it was going to be used.

The part they asked, was if they could use NM to run outlets on the back of their house. Go back and re-read my original post, at post #2.

These threads as usual become nothing more than a bicker fest, because you end up arguing pointless stuff, that goes round and round, and never stays on topic, after the fifth posting.
 
#23 ·
Care to cite those cases, due to the only time you would be able to have NM outside, is at a junction box to attach a light, coming into an attached junction box on the outside of the structure, that the NM enters in from inside the structure.

Even under porches, the only time you can run NM, is inside the "attic" space of the porch roof. Otherwise if it is exposed underneath with no sheathing, it is UF or conduit with THHN/THWN inside, to the junction box. You can transition from NM to the UF or THHN/THWN at the junction box at the wall, and that is only how far it can go when out in the elements.

Now if the space is an "All Season Porch", it is again dependent on your area, what they allow for use in that area, and how they classify the space for use in electrical wiring practices.

My area, you cannot use NM in an All Season porch even. It has to be conduit or UF, because it is considered an area that is not a part of the inner area of the structure.

Again, rules vary area from area, and each area can enforce them as heavy or lightly as they want.
 
#25 ·
Well Greg, I spent a little time looking for the code section I *thought* my responses were based on...and as I'm sure you all already know, it's not there.

So I apologize for being so stubborn lol...and more-so to the OP for giving false information.

I just read another thread regarding what boxes to use outside vs. inside, and a very well code-versed and respected member answered that the person could use "the same boxes as inside since it was protected from weather" (more or less paraphrased).

Maybe that's what I had in my head when I was so adamant about spouting off incorrect info....who knows. At any rate, I was wrong...you were right.

:notworthy::notworthy: