NM in Liquidtite

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Re: NM in Liquidtite

Confused :confused: all thats between my shower and the romex going to the shower can is 1/2 inch of drywall.Is drywall a moisture barrior ? Guess it's better than pvc.What about all the other stuff in the bathroom ? And we all know the mirror fogs up and the lights over it dry it up :confused:
 
Re: NM in Liquidtite

Jim you have made a good point and just about had me swayed until I thought about something.
The area in question (bathroom) is part of conditioned space. The LTNMC on the outside is not.
The area in question (bathroom) is not subjected to saturation of rain. The LTNMC on the outside is.
And last but not least, the area in question (bathroom) is inside the house. The LTNMC on the outside is not.
:)
 
Re: NM in Liquidtite

Actually most newer construction uses "moisture resistant" drywall in high humidity areas, granted this doesn't mean moisture proof.

I wouldn't be as worried about the affects of this bath room moisture on concealed NM as I would about the toxic (possibly lethal) molds that can grow behind these walls.


Roger
 
Re: NM in Liquidtite

Originally posted by apauling:
it's still quite simple, the inside of above ground pvc is by code not "WET".
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It's even simpler: if the conduit is installed outdoors, so are the conductors within. Even a proven-completely-watertight conduit run must contain conductors rated for the location. The environment within a conduit is not separate from that without.
 
Re: NM in Liquidtite

wires inside a conduit are seperate from the outside of the conduit for several conditions, including weather.

maybe we should put this topic up there with afci safety, proven-unsafe-wiring-methods-without-any-statistics that need to be remedied. all those failed heat pumps from nm, count em up. wow,... 0.

if this were such a real problem, there should be evidence of failure where ever nm enters outside metallic raceways and equipment. my expereience with remodels included the old nm in outside enclosures, wet by the opinion of many here, and the only damage i could find was from heat, chemicals, animals, physical contact and other events such as electrical shorts and fires, but not dampness. dampness with even the newer nm, seems to do in the other environments first, but i also never used old nicked wire, and nicked wire is the same whether thhn or thwn, or whatever.

although i disagreed with fema's local administrators about this issue, i will post that they considered a meger test of the wiring in a house to be adequate to prove it safe, even with long term inundation. however, this may not be the current operating philosophy.

paul

bob, it warms my heart and soul to know that we agree as much as we do. :D

paul :cool:
 
Re: NM in Liquidtite

Originally posted by electricmanscott:
Originally posted by jwelectric:
I was sitting in the truck talking with my helper when this call came. The windows were getting foggy and hard to see out of so I would presume that I was in a damp place.
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Looks like someone has gone from writing code arguments to romance novels. :D
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LOL

That's awesome, Scott, well done. :D
 
Re: NM in Liquidtite

FYI,

Rectorseal PVC conduit cement 633,grey electrical,instructions state " first use Primer" then quickly while still wet apply cement.
 
Re: NM in Liquidtite

Well thank you Frank.So to follow manufacturers instructions correctly and to have a code compliant install we do in fact need a primer.
 
Re: NM in Liquidtite

Frank,
Is that a UL listed product for PVC conduit? I dn't find that company name in the UL directory for PVC conduit cement.
Don

[ October 26, 2005, 07:18 AM: Message edited by: don_resqcapt19 ]
 
Re: NM in Liquidtite

The 2005 handbook comentary says " that it is intended that the inside of a raceway in a wet location or installed underground be considered a wet location. Therefore the conductors contained therewithin would be required to be suitable for wet locations."

This, though not part of the N.E.C. language certainly supports the language contained within the N.E.C. , and the opinion expressed is an informed one.
 
Re: NM in Liquidtite

then, logically, panels mounted on exterior walls are wet and breakers and other devices for installation in those panels must be listed for installation in "wet" environments. Can you show me the listings for the currently installed breakers? Or is this more of the we're-only-worried-about-the-conduit argument, not the obvious and logical extension of that argument.

I can't see implying one is wet without the other.

paul
 
Re: NM in Liquidtite

Originally posted by apauling:
then, logically, panels mounted on exterior walls are wet and breakers and other devices for installation in those panels must be listed for installation in "wet" environments. Can you show me the listings for the currently installed breakers? Or is this more of the we're-only-worried-about-the-conduit argument, not the obvious and logical extension of that argument.
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Paul, that would be a manufacturers concern. If we are using a brand x weather proof panel or load center, then brand x breakers would be listed for use in that panel.

Roger
 
Re: NM in Liquidtite

they would still need to be listed as wet. if we want to nit pick over nm, not seeing a wet listing for the breakers is illogical. NM is perfectly legal as is by code, and arguing that beakers are also is meritless, as the argument is about extending the "wet" area to areas now considered damp by many.

If NM needs to be TW to be okay in above ground exterior conduit applications, then breakers need to be listed for "wet" applications. If the inside of a short run of pvc or lt is wet, then the insides of gutters, panels, and exterior opening outlets are also wet. If NM is not okay in one of those, it should not be okay in the others. And thus, if NM is not okay in short runs of lt and pvc (above ground), it implies that terminating NM in exterior opening boxes should also be a problem. a very big can of worms.

paul :cool:
 
Re: NM in Liquidtite

Paul RNMC,LFNC or any method that is listed for a wet exterior location and installed above ground then there is no requirement for a wet location rated conductor to be installed .Now put them under ground and there`s you can of worms.
As far as an exterior wet location panel that has all branch circuits that do not go in a slab or underground where is the requirement for wet location conductors in the NEC?You wont find it because it is not there.The exterior of the conduit might be in a wet location but as long as above grade alls good ,the interior of the wireway is not wet nor damp so there is 1 thing left DRY and NM is acceptable.
 
Re: NM in Liquidtite

Part III of 240 gives permission to install a panel and breakers in a wet location.
240.32 Damp or Wet Locations.
Enclosures for overcurrent devices in damp or wet locations shall comply with 312.2(A).
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Part II of 334 forbids the installation of NM cable in a wet location. These people who wrote this book knew what they were doing.
 
Re: NM in Liquidtite

allen: please read the other posts, of course it is as you say. the argument is that it still is a wet condition.

jw; if a panel is a wet location nm shouldn't be there either according to the logic being argued here.

paul
 
Re: NM in Liquidtite

Originally posted by apauling:
allen: please read the other posts, of course it is as you say. the argument is that it still is a wet condition.

jw; if a panel is a wet location nm shouldn't be there either according to the logic being argued here.

paul
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Why?
 
Re: NM in Liquidtite

May be installed in damp or moist locations.
NM-B NO
NMC-B Yes
NMS-b NO

Has corrosion, & fungus resistant outer covering.
NM-B NO
NMC-B YES
NMS-B NO

May be installed where exposed to excessive moisture.

MN-B NO
NMC-B YES
NMS-B NO

does this help?
 
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