LFNMC in a slab plumbing chase ?

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brantmacga

brantmacga

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Asked to wire a new house .... slab done, framing done.

Met with customer today, and they made no provisions for electrical to the kitchen island.

There is a 2” plumbing chase with the hot/cold PEX lines, and it appears to have long radius elbows.

I don’t see anything in article 356 that specifically prohibits me from installing LFNMC inside the chase. Securing rules don’t apply if it is “fished”; I would transition to PVC where the chase comes up into the wall. It looks like I can get 1/2” flex in there, which is all I need.

Am I overlooking something that would prohibit this install?


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Pulling Carflex into a 2" that already has two PEX lines in it? Well, my first thought is "good luck."

I'm in the UF camp. And pull lube maybe.

Is NM allowed, by any chance? That'd be even easier if so.
 
LFNMC in a slab plumbing chase ?

MAC702 said:
Is NM allowed, by any chance? That'd be even easier if so.
Click to expand...

I wouldn’t think the chase in the slab would be considered a dry location. Idk how well they glued that together. My concern was moisture in that pipe under the slab. Am I wrong thinking that?

I guess UF would solve that; my personal preference is to not have anything under the slab that I can’t pull out or add to if needed.



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Good point. I'd pull UF. Just pull harder. I still can't see Carflex being doable without a lot of swear words, if at all.

If adding is even remotely possible, pull in a 3-conductor UF and have at least a MWBC available later.
 
Yes. I'm a pessimist. I'm already thinking it's going to be harder than it looks. Just pulling in one seems like a PITA. 12/3 is 1/3 harder to pull. Two 12/2's is probably more than twice as hard. Then again, they might shoot right through. Doesn't hurt to try it first, so that's a good idea.
 
MAC702 said:
Pulling Carflex into a 2" that already has two PEX lines in it? Well, my first thought is "good luck."

I'm in the UF camp. And pull lube maybe.

Is NM allowed, by any chance? That'd be even easier if so.
Click to expand...

I wouldn't think it's an issue, but you might want to confirm that the lube is compatible with the PEX.
 
Our Union Hall sent a letter to every member about this, only just used the words phone calls; I had an apprentice tell me he was texting not on a phone call!
I on the other hand did make a phone call about him to the Hall; nothing happened, I guess we needed him to meet some x% on the job need.
 
gadfly56 said:
I wouldn't think it's an issue, but you might want to confirm that the lube is compatible with the PEX.
Click to expand...

I agree. Probably not an issue but that’s something that would cause me to at least think about it an extra minute.
 
At least the left a chase. We were wiring a new development and the first few houses were on slabs due to the water table. I asked the guy in charge of the development if they remembered to put a pipe in for the island outlets when they poured the slabs. Blank stare. They were sawcutting the slab after the fact. :slaphead::lol:
 
brantmacga said:
I wouldn’t think the chase in the slab would be considered a dry location. Idk how well they glued that together. My concern was moisture in that pipe under the slab. Am I wrong thinking that?

I guess UF would solve that; my personal preference is to not have anything under the slab that I can’t pull out or add to if needed.



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Click to expand...

IMO, In the slab would be a dry location, (after all, it is above the moisture barrier installed for that reason below the slab wouldn't.
 
Strathead said:
IMO, In the slab would be a dry location, (after all, it is above the moisture barrier installed for that reason below the slab wouldn't.
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The nec disagrees--- if the slab is on grade then the conductors in a raceway in the slab must be wet location rated.

Definitions

Location, Wet. Installations underground or in concrete slabs
or masonry in direct contact with the earth; in locations subject
to saturation with water or other liquids, such as vehicle washing
areas; and in unprotected locations exposed to weather.
Click to expand...
 
Dennis Alwon said:
The nec disagrees--- if the slab is on grade then the conductors in a raceway in the slab must be wet location rated.

Definitions
Click to expand...

Sorry Dennis, but your definition defies your statement. "in direct contact with the earth" is the key here. Above the moisture barrier is specifically NOT in contact with the earth.
 
Strathead said:
Sorry Dennis, but your definition defies your statement. "in direct contact with the earth" is the key here. Above the moisture barrier is specifically NOT in contact with the earth.
Click to expand...

In residential monolithic slabs, our electrical & plumbing conduits are always below the moisture barrier, as the concrete is poured directly on top of it. To be above it would be embedded in the slab.


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Strathead said:
Sorry Dennis, but your definition defies your statement. "in direct contact with the earth" is the key here. Above the moisture barrier is specifically NOT in contact with the earth.
Click to expand...

You left out the word "masonry", that is what they are saying is in direct contact with the earth. The masonry slab would be in direct contact with the earth and therefore a wet location.
 
brantmacga said:
In residential monolithic slabs, our electrical & plumbing conduits are always below the moisture barrier, as the concrete is poured directly on top of it. To be above it would be embedded in the slab.


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I understand, and in most of the construction I do, the slab on grade conduits are below the moisture barrier as well. However, this is usually done exclusively for scheduling purposes, they don't want to give us time to put conduits in above. In the rare residential that I have done, we usually put an island conduit in above the moisture barrier for the specific reason that romex can be run through it. What I don't quite get about your statement is what I may be misinterpreting as a problem with the conduits being embedded in the slab. Please elaborate.
 
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