EXISTING underground wiring from wall to kitchen island

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  #1  
Old 10-06-14, 05:11 PM
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EXISTING underground wiring from wall to kitchen island

House is concrete slab in South Florida.

After I opened up the kitchen wall to redo some of the wiring I noticed the previous owner did multiple wire splices inside the wall during his last kitchen remodel, these splices are not in any accessible junction boxes. I have since corrected all of those, either by replacing with a longer run or by adding junction boxes where needed.

However I have one spot I am unsure about.

There is a run of wire (12-2 NM-B) that runs down into the concrete slab, via a blue ENT conduit, this conduit runs below and comes back up about 10 feet or so away, under the kitchen island to supply the power to the dishwasher and garbage disposer. I am going to get rid of the garbage disposer, so it will be just for the dishwasher in the future.

First, is it OK to run this blue ENT conduit under the slab? I don't know if it's inside the slab all the way, or whether it went past the slab into the subsoil below. Second, is it OK to use this ENT conduit as a raceway for NM-B wires for an underground application like this? I would have preferred to use PVC but I don't want to break up the floor and walls and the island cabinets, so I am hoping this is OK.

Third, the NM-B wires is a bit short, it does reach the new junction box I put in but I have to sort of pull it pretty tight, tighter than I wanted. I can't move this junction box because if I move it closer, I am further away from another line that comes from the above.

One thought I have is to pull this NM-B wire out, and replace it with a longer run of wire. I disconnected one end and pulled on the other, and it's very tight. I didn't try too hard as I don't want to end up with a wire stuck half way. So I wanted to know is if I pull out this 12-2 NM-B wire, how much difficulty will there be to run another run of 12-2 NM-B wire through this same ENT conduit? I don't know if the ENT conduit was run straight or twisted and coiled.

Thanks in advance for any comment.
 
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Old 10-06-14, 05:14 PM
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What are you calling ENT ?
Do you mean EMT.... thin wall steel conduit or some kind of plastic conduit ?
 
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Old 10-06-14, 05:50 PM
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I meant ENT conduit, the blue colored plastic flex conduit was used to go from the bottom of the wall down to the slab and up the other end below the kitchen island. Then they passed a 12-2 NM-B wire through it.
 
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Old 10-06-14, 06:36 PM
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PJ this is commonly called Smurf tube. It is like a plastic Greenfield that comes in 100 foot coils. You can also buy 10 foot sticks at the big boxes.
 
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Old 10-06-14, 06:43 PM
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[ATTACH=CONFIG]39562[/ATTACH]

Is it OK to use this conduit underground?

What is the chance I can pull a 12-2 NM-B wire out of it and pass another one through it without knowing how it may be twisted or coiled underneath?

If I do decide to pull the existing NM-B wire out, is it better I pull in a new UF-B wire?
 
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Old 10-06-14, 06:57 PM
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ENT is not permitted to be direct burial in the Earth. It is allowed to be encased in concrete that is on, or below grade, with approved fittings. ENT can be placed on sand or "approved screenings" (NEC quote, not mine ) when encased in concrete.

If it was me, I would pull out the cables, pulling in a pull wire at the same time, extend the conduit and pull in new THHN/THWN wires.
 
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Old 10-07-14, 09:16 PM
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Tolyn, I thought about running THHN conductors through that blue tubing but the issue as you said, it is OK to be encased in concrete but not buried in dirt, and there is no way for me to know how it was done. Judging from how poorly the general wiring was done in this property I am not going to assume it was done properly. The kitchen island is not original and the smurf tube was added, may be he only chipped enough concrete to bury the tubing, or may be he punched all the way through and buried it deeper. So I am thinking the extra jacket of the NM-B serves as an additional layer of protection.
 

Last edited by MiamiCuse; 10-07-14 at 09:46 PM.
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Old 10-07-14, 09:27 PM
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By the way, when you connect this ENT conduit to one of those blue couplings, do you have to push it in real hard? I can't seem to get the tubing in past the "tabs" but I am guessing it is supposed to bottom beyond the tabs. I didn't try using the PVC cement, may be that would soften the materials enough for an easier joint? Couldn't find the recommended blue Carlon cement at the big box store, I wonder if I can use the PVC cement I have laying around for PVC plumbing pipes? I have blue lava glue, rain or shine cement, and heavy duty cement.
 
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Old 10-07-14, 09:37 PM
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No cement needed just push till it locks in place.

Pros, I was once told you could use schedule 40 PVC conduit fittings and cement instead of the snap lock firings. Is that true?
 
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Old 10-08-14, 08:15 AM
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Couldn't find the recommended blue Carlon cement at the big box store, I wonder if I can use the PVC cement I have laying around for PVC plumbing pipes?
From Carlon Codes/Standards:

WHY IS THERE A SPECIAL CEMENT FOR ENT?

CARLON ENT BLUE “QUICK-SET” CEMENT (Part # VC9993 or VC9992) must
be used with Carlon Flex-Plus® Blue® ENT (Electrical Nonmetallic Tubing) and
cemented fittings. First of all, you may notice that this is the only cement that is
blue. Common sense dictates the reason is to match the Blue® ENT. Secondly,
you may notice that this is the only cement that comes with a brush. All the
others come with a dauber. It is recommended that the light coat of cement is
brushed around the ENT, not in the longitudinal direction. All excess cement
should be brushed out of the ENT grooves. Essentially, the “grooviness” of the
ENT warrants the use of the brush as an applicator.
http://www.carlonsales.com/techinfo/...kSetCement.pdf


From Carlon Q&A:

On your ENT product do I need to glue the fittings on or do they just use the snap in feature?

Solvent cement is not required when using Carlon's snap on fittings.


Pros, I was once told you could use schedule 40 PVC conduit fittings and cement instead of the snap lock firings. Is that true?
From Carlon Q&A:

On your ENT product do I need to glue the fittings on or do they just use the snap in feature?

When using schedule 40 fitting ENT solvent cement is required. Solvent cement
is not required when using Carlon's snap on fittings.
http://www.carlonsales.com/techinfo/faqs/FAQ-ENT.pdf
 
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Old 10-08-14, 08:26 AM
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Thanks Joe.

.
 
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Old 10-08-14, 11:09 AM
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Thank you Joe.

So if the cement is not "required" but if you do decide to use cement it must be the special blue cement.

This lead me to conclude that for everyday use in wall cavity no cement is needed, but if you want to encase it in concrete to make it water tight that's when you use cement.
 
  #13  
Old 10-08-14, 07:04 PM
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No, you are after concrete tight, not water tight. No glue or cement is needed to be concrete tight.

What fittings may be used in applications that require concrete encasement?

• All the fittings mentioned in question 2.
• The A243 series terminators require a foam washer to be concrete tight.
• None of Carlon’s fittings are required to be wrapped in tape for concrete
encasement applications.
http://www.carlonsales.com/techinfo/faqs/FAQ-ENT.pdf


OR......use the blue cement with schedule 40 fittings.
 
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