nm cable

[don_resqcapt19]

Are ALL raceways installed outside considered to be in a wet or damp location? What would be the code reference?

Look at 300.9 in the 2008 code. The section doesn't use the word outside. It says that the interior of raceways that are installed in wet locations is also a wet location.

 

[buck33k]

Look at 300.9 in the 2008 code. The section doesn't use the word outside. It says that the interior of raceways that are installed in wet locations is also a wet location.

Your right. When I see the words "above grade" I assume it is outside but not necessarily.

A conduit could be in a wet or dry location outside or inside. As in an indoor carwash or well protected under an eve of a building. Concerning the OP, the NM in the wp bellbox and the conduit feeding it could be in a dry location outside.

 

[LawnGuyLandSparky]

There isn't one, thats the point. If a raceway outside is a wet location, shouldn't a box be too since just as likely to accumulate moisture?

If the box is mounted to the outside of the house, I'd say yes. But a box recessed in the wall is actually inside the house.

 

[infinity]

I just got back from a 2008 code update class sponsored by the Idaho chapter of the IAEI. This issue was discussed there. As it stands now, technically NM could not be run to an outside fixture.

I still disagree. Until a code specifies that the inside of a box is a damp or wet location when installed in either, I don't see how this is a violation. Does the wording of the NEC address the inside of boxes like it does raceways?

 

[iwire]

Because in 334.12 (B) of the 2008 they added to uses not permitted "In wet or damp locations" So, theoretically any location outdoors whether in a box, conduit, is considered to be wet or damp location.

If the code was to say the inside of an enclosure is a wet location that would be the end of switches, receptacles, fuses and breakers in outdoor locations as none of those items are intended for wet locations.

 

[Brent Peterson]

I can understand making the inside of counduit run a wet location if the water can enter it because depending on the way the pipe is run water could collect keeping the conductors wet.

I don't do much resdential work, and the light fixture that has been given to me to install on the outside of a building would not guarantee that water could not get in the box. Most boxs that are installed in a out door location will show evidence of water collection in them unless they are made to drain even bell boxs.

So if collecting water is the reason for a interior of a given pipe run to be called a wet location I can understand the interior of a boxs being called a wet area, unless it is made to drain or water can freely through the bottom.
But from what I read and was told on the 2008 code update the outside of a building would be a wet area the light fixture would be installed in the wet location and some how the wires are going to have get there and NM will not be allowed in a damp or wet location.

 

[stickboy1375]

I don't do much resdential work, and the light fixture that has been given to me to install on the outside of a building would not guarantee that water could not get in the box. Most boxs that are installed in a out door location will show evidence of water collection in them unless they are made to drain even bell boxs.

If you read the directions, your suppose to run a bead of silicon around the fixture backplate....

 

[Brent Peterson]

You can put silicon or a gasket on a box eventually water will get in the box directly or by condensation. Most bell boxes that have been installed for several years will have the bottom twist of when open due to corrosion. Most boxes that don?t' even attempt to keep the water out will not have a problem

 

[Brent Peterson]

sorry will have bottom screws twist off 10-20 years

 

[stickboy1375]

You can put silicon or a gasket on a box eventually water will get in the box directly or by condensation. Most bell boxes that have been installed for several years will have the bottom twist of when open due to corrosion. Most boxes that don?t' even attempt to keep the water out will not have a problem

Thats funny because I never have a problem, Bell boxes need to be used with a thread sealer on all threaded entries... which I never see except for the boxes I install...

 

[Brent Peterson]

Thats funny to becuase I am not talking about boxs I have installed either I am talking about why does the nec consider the inside of a race way a wet area which assuming everbody knows you would use thread sealer on the threads how does the water get there threw boxs? does this make the box a wet area there for I can not run nm cable. Bell Boxes not all but alot of them get water in them in time or aleast in area where we have freezing and thawing adding to the problem.

 

[don_resqcapt19]

I am talking about why does the nec consider the inside of a race way a wet area which assuming everbody knows you would use thread sealer on the threads how does the water get there threw boxs?

I am not aware of any thread sealer that can be used on conduit threads. That product would have to be listed for the purpose and the problem would be the grounding path. Threaded conduit couplings have straight threads and do not make a water tight seal.

 

[mdshunk]

The old man I apprenticed under used a thread sealing product on RMC fittings underground called "Red Lead". It was red in color, and had fibers mixed in it. He claimed it was conductive, and I suspect that it probably was. Very much like Kopr-Shield that T&B makes. They market that as being able to improve the conductivity of raceway connections.

 

[Minuteman]

Sounds like another "wet romex" question to me. All I know is, what you described would be allowed here.

 

[stickboy1375]

EC&M or nec digest had a big article on this subject, I will try and find it...

 

[don_resqcapt19]

Marc,
Both red and white lead were used as pipe sealers in the past. I don't see where the T&B product provides any sealing. It is intended to protect the threads from corrosion and provide a better fault return path.

 

[tom baker]

why does the nec consider the inside of a race way a wet area .

Condensation for one.
Electrical fittings are not water tight. Plumbing couplings have a taper, electrical do not.