outdoor receptacle and back clamp

[terpom]

Hi,

I have a question about a surface mount outdoor receptacle box. This is an AL box, with a threaded hole in the back, top and bottom. A 1/2" NM-B clamp can screw into these holes.

Is it acceptable to put a hole in the outside wall of the house and run NM-B in the wall into that clamp on the back of this box? It seems to me, that the clamp is not weatherproof. I guess the clamp is inside the house wall but just barely; the box is clearly outside. I've seen many "how to" web sites show just this type of installation, does it meet code?

Thanks

 

[bphgravity]

Re: outdoor receptacle and back clamp

This is one of those transition areas where two different locations are involved with one installation. From a code point of view, 314.15(A) is clear that all fittings used in damp or wet locations be listed for the location. The cable clamp you describe is certainly not. However, if the clamp is placed to the back of the box, the box is mounted flush to the wall, and the box is sealed around its edge, moisture shouldn't find its way in.

I guess bottom line is to consult your AHJ, if they allow it than do waht you can to ensure no moisture can enter through that point. A better fitting would probably be a bettert choice such as a weatherproof cable connectors, like those generally assoicated with tray cable. They aren't exactly listed for use with NM cable, but they seem to work well for this application.