So are you saying to cut the concrete, run 12/3 romex, and then pour new concrete right over the romex? I thought that was what I needed conduit for, and the romex went inside the conduit. No???
Romex (type NM cable) is not allowed in wet locations or embedded in concrete [see NEC article 334]. Buried is considered a wet location, whether in conduit or not [NEC 300.5(D)(5)]. So you can't use Romex, even within conduit.
You could use type UF, which is rated for direct burial, but it is not rated for embeddment in concrete. So you would need to sleeve the UF in conduit where it would be passing through the concrete [see also NEC 300.5(D)(1), perhaps].
Cheers, Wayne
You'd have to use UF, not Romex (NM) if you were to direct bury it. Conduit is cheap and allows for pulling new or additional conductors in the future. You generally don't run Romex in conduit either, you usually pull individual THHN conductors. Moisture in the PVC conduit will certainly happen, but rarely bothers the conductors in it.
They are correct. Us the UF, not romex. I wouldn't run conduit in any place that has a chance of flooding even by a power outage to the sump. Lou
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If he does trench the concrete., Smurf tube is probably the best way to get the wire in it. That is listed for burial in concrete so he could just backfill the trench with concrete and be done.
Smurf tube being ENT, the flexible blue sutff
I like your smurf tube name.
ENT seems pretty fragile. Seen significant problems?
Smurf is really pretty tough. It can be used anywhere you can use Romex plus embedded in concrete.
As an "unelectrical" anecdotal study, I am also using a piece of 3/4" smurf to sleeve the steering cable on my boat. 12 years later the Florida sun, salt water and heat have not hurt it a bit. It didn't get hard and crack as I suspected it might. Carlon must have some U/V protection in it. I personally think the listing may be somewhat conservative.
A word of warning for Smurf tube. Pulling the wire can be harder. I wouldn't use 1/2" unless it is really short run. Don't bend it unless you have to. You can't put more than 360 Deg bends between junction boxes. I would pull the wire before I covered everything up.
Carlon would disagree with you on that. I was in a meeting with a number of building officials and the carlon rep. He presented data that suggested you could "push" wire through 720 degrees of bend and said they were trying to get the rule changed. What he did say is you have to support the ENT at both ends of every bend and pull the straight parts straight. If it is loose it will "belly" and bind the conductors. I would agree the extra buck for 3/4 is probably worth doing though. Once that raceway is in the concrete, you don't want to be chipping it out again because your plans changed. It would also allow you to exploit a loophole in the low voltage rules. If you pulled a "cable" like Romex, UF or better MC through there you could also pull in a CAT5 since cable jackets are "separation".
In article , snipped-for-privacy@aol.com writes: | On Thu, 13 Dec 2007 18:53:53 -0500, Terry | wrote: | | >A word of warning for Smurf tube. Pulling the wire can be harder. I | >wouldn't use 1/2" unless it is really short run. Don't bend it unless | >you have to. You can't put more than 360 Deg bends between junction | >boxes. I would pull the wire before I covered everything up. | | Carlon would disagree with you on that. I was in a meeting with a | number of building officials and the carlon rep. He presented data | that suggested you could "push" wire through 720 degrees of bend and | said they were trying to get the rule changed. What he did say is you | have to support the ENT at both ends of every bend and pull the | straight parts straight. If it is loose it will "belly" and bind the | conductors. | I would agree the extra buck for 3/4 is probably worth doing though. | Once that raceway is in the concrete, you don't want to be chipping it | out again because your plans changed. | It would also allow you to exploit a loophole in the low voltage | rules. If you pulled a "cable" like Romex, UF or better MC through | there you could also pull in a CAT5 since cable jackets are | "separation".
Just to be clear: you aren't saying that this "loophole" is unique to ENT, are you?
Dan Lanciani ddl@danlan.*com
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