PVC under slab = wet location?

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220/221

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We got called on this today for the first time ever.

Residential kitchen island. We install a PVC sleeve stubbed up in the wall and under the island cabinets and run the NM straight thru to the receps, cooktop or whatever.

Inspector wants UF and I assume because he's considering the PVC under slab as a wet location.

What's the call? I'm at my cabin and don't have my code book with me.
 
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Section 300.5(B) Listings. Cables and insulated conductors installed in enclosures or raceways in underground installations shall be listed for use in wet locations. Nm cable is not listed for a wet location 334.12 (B) (4)
 
Here is the definition of wet location:

"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."

You will notice that it specifically states that installations in concrete slabs in direct contact with the earth are wet locations.

Also the 2008 NEC has clarified that the wiring installed within raceways in wet locations must be rated for wet locations. Here is what the new section says:

"300.5(B) Wet Locations. The interior of enclosures or raceways installed underground shall be considered to be a wet location. Insulated conductors and cables installed in these enclosures or raceways in underground installations shall be listed for use in wet locations and shall comply with 310.8(C). Any connections or splices in an underground installation shall be approved for wet locations."

Chris
 
That's why I have never been called on it, because the 2008 code clarified it.

I guess I will have to throw some UF on the trucks.

Great, I HATE UF.


Wait....can I put the UF directly in the concrete?

Nevermind, that seems like a BAD idea. Some knuclehead will damage it installing the cabinets.
 
As you probably know we don't build homes on slabs here...but sometimes there might be a need to do that in a homeas you suggested and the preferred way would be with PVC and then use THWN, but UF seems a lot easier.

IIRC, the first time I saw homes built on slabs was in CA, and they were feeding the island circuits in PVC with UF cable.


Of course all of our commercial buildings are on slabs and the underground is usually spec'd PVC in the slab with an RMC 90 and short piece of RMC as it emerges from the slab.
 
220/221 said:
That's why I have never been called on it, because the 2008 code clarified it.
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The rule in 300.5(B) is not new or changed for the 2008 code. That was placed in the code for the 2005 edition, but was already required based on the definition of location, wet in Article 100. The change for 2008 was new section 300.9 that applies to above grade raceways in wet locations and says that the interior of such a raceway is a wet location requiring the use of conductors or cables listed for wet locations.
 
So if the slab is sitting on a layer of plastic sheeting, is it 'in direct contact with earth'?
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Good catch. This is poorly written IMO.

I does say "" Installations underground or in concrete slabs or masonry in direct contact with the earth""

Hmmmm....is ABC considered masonary or earth.

It's not earth. It is placed on top of the earth, usually a few inches deep.

I don't think it's masonary either.

Another fine example of short sighted authors.
 
I don't think so, it says, underground or ' in slabs ' is wet location.
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I thought that at first too Frank but when I re read it, it says in slabs--- in direct contact with earth meaning the slab has to be in direct contact with earth....which I contend its not.

IMSO if the PVC is on top of the plastic your install is okay.
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If the PVC is on plastic it doesn't affect the status of the slab. If the slab is on plastic, OK.
 
Every time I read this, I see it differently.

Installations underground or in concrete slabs or masonry in direct contact with the earth

Is it A:

1. underground in direct contact

2. in concrete with direct contact

3. in masonary in direct contact


Or is it B:

1. Underground

2. in concrete

3. in masonary with direct contact.



I read it as "A".....or "B".




Hmmmmmm......the rule is You can't put too much water in a nuclear reactor. It is approaching meltdown.

What do you do?

Put more water on it?




.
 
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wirebender said:
The plastic is there as a moisture barrier.

No moisture, no wet location.
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Wet Location:

1. underground

2. or in concrete slabs ** a concrete slab on the 3rd floor is a wet location

3. or masonary in direct contact with the earth.

masonary above direct contact with the earth is not a wet location.
 
Installations underground or in concrete slabs or masonry in direct contact with the earth


They used "or" between the 3 items and no comma after masonry so I suppose that makes them separate.


Every time I read it I change my mind. Now I am seeing underground as one thing and concrete slabs/masonry as another beacause they say in concrete slabs or masonry, not in concrete slabs or in masonry.

Gah!

I need an english major to help me out here.



a concrete slab on the 3rd floor is a wet location
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Really? I wouldn't have thought that. If that's the case, case closed.
 
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Let's try it again

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.
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If it is in concrete and in direct contact with the earth then it is wet location. 3rd floor concrete doesn't classify as wet location.

I do not see how a vapor barrier changes this definition esp. since the vapor barrier is usually above the stone and the pipe is in or under the stone. Even if the vapor barrier were lower I don't believe the definition will help out. IMO
 
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