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#191397 - 12/27/09 12:29 AM wet location  
leland  Offline
Joined: Aug 2007
Posts: 853
Lowell area, Ma. USA
Brain block and too lazy to look right now (sorry).
Now I know NM is not rated for 'WET' location,but ok for Damp.
I also understand anything in conduit under ground is 'wet'.

So to the point: IF I run NM across an open ceiling (not allowed above a drop ceiling),poke thru the out side wall with PVC,LB down into a bell box with a WR GFCI and an 'in use' cover.

Is that cool? Commercial application.

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#191398 - 12/27/09 12:43 AM Re: wet location [Re: leland]  
Jim M  Offline
Joined: Aug 2001
Posts: 457
Chestertown, MD, USA
Most seem to consider NM into the back of a disco or box ok. Running it thru a LB is not ok. You would need to switch wiring methods at the plane of the wall.

#191399 - 12/27/09 12:45 AM Re: wet location [Re: Jim M]  
leland  Offline
Joined: Aug 2007
Posts: 853
Lowell area, Ma. USA
So if I install a change over connector,is that good?

#191400 - 12/27/09 01:11 AM Re: wet location [Re: leland]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,140
Why not just use UF?

Greg Fretwell

#191402 - 12/27/09 02:03 AM Re: wet location [Re: gfretwell]  
leland  Offline
Joined: Aug 2007
Posts: 853
Lowell area, Ma. USA
mechanical protection Greg.

Straight from panel to outside wall location.With NM, all interior.
Now I drill a 1" hole from out side in,sleeve a piece of 1/2 pvc,inside out/mount an LB and drop down to the WP box.
The NM just slides in the conduit,thru the LB and terminates on the WR GFCI rec.

IMO,the conduit is a sleeve. BUT... Is it a wet location?

#191404 - 12/27/09 03:01 AM Re: wet location [Re: leland]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,140
It is certainly a wet location but UF will go anywhere NM will go plus being OK "wet". (run in in your RNC sleeve) If PP is important, pipe it all the way and use THWN.

Greg Fretwell

#191429 - 12/29/09 01:36 AM Re: wet location [Re: leland]  
Niko  Offline
Joined: Aug 2006
Posts: 356
Campbell, CA
334.10(A)(1) states that the NM cable can be installed in NORMALLY DRY location. woudn't you agree that the interior of LB is NORMALLY DRY location? depending on the location, i can't think of any immediate time that i have opened a LB cover and it was wet inside.

Besides i think sometimes it is O.K. to not follow the code verbatim, and make some exception, because I know from experience that it will be a safe installation. just like leland's installation.
Of course it all depends on the AHJ.

Be kind to your neighbor, he knows where you live

#191432 - 12/29/09 03:33 AM Re: wet location [Re: Niko]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,140
I suppose the AHJ makes the rules but article 100 says wet locations are "... unprotected locations exposed to weather".
In 2008 they also removed the confusion about above grade wet location raceways
300.9 Raceways in Wet Locations Above Grade.
Where raceways are installed in wet locations above grade, the interior of these raceways shall be considered to be a wet location. Insulated conductors and cables installed in raceways in wet locations above grade shall comply with 310.8(C).

Greg Fretwell

#191436 - 12/29/09 09:28 AM Re: wet location [Re: gfretwell]  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,878
Brick, NJ USA
Your proposed install would get another 'nay' from me.


#191437 - 12/29/09 10:59 AM Re: wet location [Re: HotLine1]  
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Please note that the latest code edition goes so far as to ban the use of ordinary NM in even damp locations. On another forum, home inspectors are even being urged to call out crawl space NM runs as being contrary to the NEC.

I don't say I agree with this - but that's the way the code reads. First they tell you that NM allowed in damp locations ... then a few paragraphs later tell you that NM-B, the stuff we actually use, can't go into even damp areas.

The law has a principle of not entertaining petty claims. It frowns upon $1 lawsuits and 1mph speeding tickets, for example. There's even a fancy latin name for this principle.
What I'm getting at is that I would not fault an installation that had a transition to a 'proper' wiring method as soon as possible, after entering a different environment.

NM ("Romex") is an amazing material. First they expand its' use, pointing to 70+ years of use as proof that it is safe. Then they tell us we can't put it in the one place where most of it goes (crawl spaces) and require us to use AFCI's to protect it. They tell manufacturers they have to use 'wet location' conductors (Thhn/Thwn) then tell us it can't even be in damp locations.

I can't speak for anyone else, but I'm confused!

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