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#194265 05/19/10 07:30 AM
Joined: Feb 2002
Posts: 2,233
H
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In section 300.9 the NEC states that you have to use wire suitable for wet/damp locations when used in a raceway or enclosure above grade.
OK in one of the latest trade magazines, the author of a column stated that you can't use NM to feed an outside light or outside weatherproof receptacle.

I guess my question would be, is that really the intent of the code? I mean is the inside of an old work box inside the wall cavity really a damp/wet location?

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harold endean #194266 05/19/10 08:34 AM
Joined: Apr 2002
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Harold:

Greg & you can debate this till you know what freezes over.

IMHO, no issues with NMC to the box for an exterior outlet/device.



John
HotLine1 #194267 05/19/10 09:19 AM
Joined: Aug 2001
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J
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Harold, I addressed this with CT, and he is going to publish a clarification.

Jim M #194268 05/19/10 12:31 PM
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Posts: 2,233
H
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John,


The EC who questioned me with this one, called Suzanne and she feels the way that I do. If you see wires hanging outside and getting wet, then you can fail for NM getting wet. However if they keep the NM inside of the building and only installing it in the box, then I don't believe the area would be considered damp/wet location.

harold endean #194303 05/22/10 08:53 AM
Joined: Jan 2005
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One of the thingd I 'love' about new code editions is all the little surprises that seem to get implemented without anyone being aware of them .... until the new code comes out, and the 'seminar riders' suddenly start off on a new crusade.

In the 08 cycle, this ban on NM in 'damp' locations was one such surprise. Romex in the crawl space? Violation! Romex through the wall into the back of an outdoor weather-tight box? Violation.

Hell, I had one clown assert that ordinary switches, place conventionally in a bathroom, were a violation, as was NM in the walls, because condensation made the area 'damp.'

I'm just as sore at the NM makers. There is absolutely no reason for conventional NM to not be rated / listed / approved for the wettest applications - even under water. Just my opinion - but I suspect that they either haven't even tried, or that there was a management decision to avoid the application.

renosteinke #194319 05/23/10 02:25 PM
Joined: Jul 2004
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G
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They could fix the water problem with NM by removing the kraft paper but I assume there is a business reason not to. It certainly isn't a technical reason. My bet ... UF costs about the same to manufacture but they can sell it for more.


Greg Fretwell
gfretwell #194331 05/24/10 08:30 AM
Joined: Feb 2002
Posts: 2,233
H
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Greg,

Actually I think I found out one reason where 300.9 might apply, where the EC runs NM out of the house and sleeves the NM in a flex tubing then into a HVAC disconnect.

harold endean #194335 05/24/10 09:48 AM
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Yes, Harold; what you describe above technically does not fly!


John
HotLine1 #194340 05/24/10 01:58 PM
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G
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When I had this conversation at Fl IAEI the consensus was if the exterior box was inside the wall it was OK to use the NM, it got a little more questionable if it was a surface mounted pancake but if there was any raceway involved NM was a tag.
The real gray area was a surface mounted bell box served from the back, but again the answer was usually no. It got into questions about if the back of the box was caulked into the wall and how the box was served.


Greg Fretwell
gfretwell #194347 05/24/10 06:30 PM
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Greg:
Thanks! That's the debate I remember.


John
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