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#182611 12/04/08 04:19 PM
Joined: Jul 2004
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G
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This came up in another "homey" forum.

Is the inside of a free standing block wall a "wet location"?

How about the inside of the exterior block wall of a building?

What is the difference?

I have no real opinion. I can make a case either way.


Greg Fretwell
2017 / 2014 NEC & Related Books and Study Guides
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Greg- I think reading the definitions of "wet" and "damp" locations says it pretty well.
There isn't any mention of block wall(s) as being either wet or damp. So I guess they are dry?
My opinion is that a block wall is not a wet location.


George Little
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Greg:
Is the free standing block wall capped?

Seriously, I have to go along with George. That's twice in two threads!



John
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I do not believe a 'block wall' is always a wet location.

Code does say that a masonry or concrete wall, in contact with the earth - such as a basement wall - is a wet location.

A freestanding wall, such as one that might be built to fence off a patio, would be a wet location IMO.

Last edited by renosteinke; 12/05/08 01:51 AM.
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Additional thought:
Interior side of an outside block wall IMHO is dry, under normal conditions.

Any wiring 'within'/'inside' basement walls in direct contact with earth, by definition is a wet location. Wiring methods on the interior surface should comply with dry locations; or in some instances possibly 'damp locations' due to condensation moisture.

As to a 'free standing' masonry wall, that's a 'judgement' call. George said block is not mentioned in the NEC. Reading ('08) wet locations, I now have to differ with him. 'Block' is IMHO opinion understood to be made of masonry/concrete.

Sorry George, I now only agree with you in one thread.




John
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L
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My opinion (not that you care)

Free standing block wall seperating 2 patios (or the like) outside.Exposed to weather.
Either inside or outside the blocks,capped or not, Wet Location.

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G
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I knew this was going to be a split decision. I have also never got a good answer as to why an exterior wall of a house is dry, right up to and including the canopy of a jelly jar luminaire.
I know there is supposed to be a seal between the luminaire and the wall but the bugs I see in them seems to tell me this is far from perfect.
We can't even keep water out of a Bell box.


Greg Fretwell
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G
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First of all, I've concluded that Greg is a trouble maker.:) And most of us inspectors are trouble makers.
Hotline1, (John) I looked in the '08 and the wording is the same as the '05 for definitions of "wet" and "damp" locations. I am wrestling with the fact that you claim a slab of concrete and a poured wall are the same thing as a concrete block or a cinder block wall. I have seen block walls that were wet/damp but that's a building issue. I guess like it says in "damp locations", some basements could be considered damp but they are basing that on a concrete poured wall. I look at the hollow core of a block and the fact that the code does not mention block walls and that's why I stake my claim.

Maybe we can disagree on this one:)



George Little
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Let's open up the question a little.

Can Romex be run inside a block wall at all? Even when the wall is in a 'dry' location?

Article 334 has some interesting twists to this question. First of all, it differentiates between different types of masonry construction. It lumps 'wet' and 'damp' locations together. Perhaps, most importantly, it differentiates between "NMC" and the other typs (NM and NMS).

Mind you, "UF" is none of these, and has its' own section. (A side note: UF can be run in masonry, but not in poured concrete).

What are the differences between NM, NMC, and NMS? I was given to understand that the first is the old cloth-covered stuff, and thet the last has yet to be produced. Is this correct? How can you tell them apart in the field?

Joined: Mar 2005
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S
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334.19(B) specifically allows NM to be installed in the cavities of block walls in normally dry locations.

Basement block walls, freestanding unfinished walls, etc, are not dry. But if the block wall is above ground, covered by a roof, and protected from the weather by siding or brick (etc), then it's a dry area. Why wouldn't romex be allowed in it?

(FYI, 334.2 defines NM, NMC and NMS :))

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