mvannevel
Senior Member
- Location
- Hesperia, Michigan
Re: Type NM cable and Article 440
Raceways on the exterior of buildings are arranged to drain in case moisture is introduced into them. NM is allowed to be installed in normally dry locations. To me a raceway, above ground, is a normally dry location.
And, just out of curiosity, how much fall is required so that a raceway will drain? 1/8 in/ft like plumbing? So 12.5 inches in a 100 ft. run on the exterior of a building? Or maybe slope it 6.25 inches from each end toward the middle and put a drain hole in the conduit so that it doesn't drain into the equipment at either end.
[ August 07, 2005, 02:55 PM: Message edited by: mvannevel ]
THWN is used without a raceway where it exits the weatherhead on service risers is it not? Open Wiring on Insulators is another that comes to mind (although the uses permitted are quite narrow). I realize that iwire is playing devil's advocate here and, in a sense, that's what I was doing with my original question. If the conduit method or enclosure doesn't provide the location, then there are any number of installations that are non code compliant. Think of the installation of a weatherproof panel on the exterior of a structure wired with NM cable. This is certainly a wet location. The enclosure is 3R, but the NM cables which terminate within the enclosure and the breakers on which they terminate aren't listed for use in wet locations. Does this mean that THWN conductors would need to be run to the interior of the structure before the NM cable would be allowed to be run? The disconnect for the A/C unit in the original question is the same scenario. It's fine to run the NM into that enclosure (it's in a wet location as well) but not to continue on with it?
Raceways on the exterior of buildings are arranged to drain in case moisture is introduced into them. NM is allowed to be installed in normally dry locations. To me a raceway, above ground, is a normally dry location.
And, just out of curiosity, how much fall is required so that a raceway will drain? 1/8 in/ft like plumbing? So 12.5 inches in a 100 ft. run on the exterior of a building? Or maybe slope it 6.25 inches from each end toward the middle and put a drain hole in the conduit so that it doesn't drain into the equipment at either end.
[ August 07, 2005, 02:55 PM: Message edited by: mvannevel ]