For installing an electrical outlet on a block wall in an unfinished basement, is it acceptable to run romex along the mudsill from the panel and then have it drop into emt where the mudsill meets the block wall?
I will be paying a sparky to make the connections, but I am capable of fastening emt and a box to a block wall and stapling cable to a mudsill if that is an acceptable practice.
I am asking because I have heard some say that it is okay to run romex through conduit, but others mention that the romex would have to be derated due to heat issues (I would assume).
Thanks.
Replies
Yes, you can do that.
You need the right type of fitting at the top so that the romex does not chafe on the sharp edge. Can't remember the name of it.
" but others mention that the romex would have to be derated due to heat issues (I would assume)."
NO! Now wire or cable have to be derated if there are more than 3 equivalent current carrying conductors bundled (or in a conduit) together for 2 ft or more.
If you have 2 2-conductor cables then you will be in the derating range.
However, for #14 on 15 amp circuits, or #12 on 20 amp there is enough "over capacity" that they can still handle the full current upto 6 current carrying conductors.
Thanks for the response. Is an anti-short bushing what you are talking about to protect the romex?
Also glad to hear that derating will not be a factor here. When you do a search here for "romex in conduit" you get an a**load of hits. Almost too many to read. <g>
Anti-short bushings are for BX (armoured flexible cable). I don't know if they make them in the size you'd need for EMT.
For your application you might be okay putting a standard union collar on the end your NMD will be running into, but my recommendation would be to make the transition through a 4" octo using the appropriate box fittings for each side.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
you need to as this question to 4lorn. around here romex is not allowed in EMT. Each district have their own rules. My inspector stop me from doing this.
around here romex is not allowed in EMT. Each district have their own rules. My inspector stop me from doing this.
That's definitely an exception to the NEC. Article 336-6(b) specifically listed EMT as an acceptable method to protect romex in suitations where it is subject to physical damage. Of course each local jurisdiction is free to make up their own rules; e.g., romex is verboten in Chicago.
One thing to keep in mind as that you could just fasten to the romex to the wall, provided it is in a location where it won't be exposed to damage. Putting it in some type of raceway is mostly a cosmetic thing.
"Anti-short bushings are for BX (armoured flexible cable). I don't know if they make them in the size you'd need for EMT."Got Home Depot up there across the Niagra Ditch? They've got'em by the bushel....
Yeah, we've been 'invaded' by HD in the last few years. They're still fighting an uphill war with the provincial 'monopolies' known as RONA and BMR to the public and 'United Merchants' inside the trade....
I still think I'd prefer to make a transition of this sort through a box. Just diving into a piece o' pipe like that, anti-short or no, doesn't seem sufficient. No strain-relief, for one thing....
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Nah, works fine....after all, we staple wires inside the wall & then push 'em into plastic boxes....better, faster, & quicker to run the wire on the sill plate, stapled to code, & then drop it into a pipe....& how often can we get better, faster, & quicker-usually, it's "pick two"!
Thanks to all for the help. If I don't end up running it through a box like Dino suggested, I'll at least swing by HD and pick up an emt to female threaded adaptor and one of those fittings to protect the romex.
I like Dino's idea of using a box there. It gives you the option to extend things from that point in the future.
-- J.S.
That, admittedly, is part of my reasoning. And when I do some kind of transition like this inside a box, I generally leave a 12" loop of the NMD inside the box in case I do wanna tap into it 10 years on down the road. Sure beats trying to yank slack outta closed walls when there isn't any to start with....
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
"You need the right type of fitting at the top so that the romex does not chafe on the sharp edge. "
I don't remember the name of it either, but HD has them. At least for flat romex to threaded and for round cable to threaded. In several different diameter ranges for round cable. So you'd also need a thinwall to female thread adaptor.David Thomas Overlooking Cook Inlet in Kenai, Alaska
The building inspector in the last town I lived in was very adamant against romex, even romex in conduit. Might want to verify romex is OK where you live.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Romex is already "derated". Conductors with 90 degree C insulation are used, but the rated ampacity is based on a 60 degree rating.
Remember there is no prohibition against using Romex in insulation filled exterior walls. Heat dissipation inside a piece of EMT would be no worse.
One can also use Wiremold-type raceways for this application, which look a little better.
Thanks to all for the help. As you can tell, I have very little electrical knowledge and do not understand the whole derating issue. I just saw the phrase pop up a few times when I was searching old threads about running romex in conduit.
By the way, thanks for suggesting the wiremold raceways. I had not even given any thought to something like that. I guess I've never been looking, but I can't remember ever seeing that stuff in a store.