Exterior sconce box and feed cable requirements

Ptron

I want to add an exterior sconce to my house in a method similar to the one shown here: http://www.thisoldhouse.com/toh/skil...193225,00.html

It would be in an exposed, i.e. wet, location. In all the information I can find, I see no mention of requirements for the box or the cable, only that the wire be THWN (which I understand most THHN wire is anyway) Can I use a standard box and MC cable if it's to be sealed like that?

secutanudu

I don't think that's considered a wet location unless you actually leave the house with the wiring, which you are not.

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Andrew

Ptron

Wow, that was fast. Thanks. I have a book that says anything on the exterior not protected by an overhang (45deg line from the overhang to the wall) is considered in a wet location. Does this not apply if the feed is not being routed externally?

secutanudu

I'll let one of the more experienced guys chime in, but I don't think it's considered wet.

When you caulk around the box, leave the bottom un-caulked so water has a place to drip out it it makes its way in. Just do the top and sides.

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Andrew

teamo

Are you mounting it on siding as shown in the link? Try one of these. No separate box needed. The siding block is the box with knockouts for the cable.

http://www.arlcatalog.com/Siding/Sid...t-in%20Box.htm

Proby

I agree with teamo.

I always wire these up with romex. I've seen debates on whether this would be considered wet or not, but I find no issue with this installation.

Ptron, why are you using MC?

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secutanudu

I've used those Arlington boxes before - I recommend them too. They sell them at home depot.

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Andrew

Ptron

That's what I have left over from another project but more importantly, to protect it from errant screws and nails. On the inside it will get fed down through the 3/4" space between the drywall and the concrete block wall. It will be virtually pinned up against the drywall next to the furring strip/stud. I have no way to add nailing plates or anything to protect romex unless I tear out the drywall. This would be a pretty short run though and I have had to cut some drywall holes elsewhere so I guess what's one more?

Also, I didn't do a very good job of explaining the situation in the OP. I want to add a sconce but this is in addition an existing one already mounted on a box (I think. It's mostly covered by siding. The bracket could just be screwed into the concrete. Probably is now that I think about it.) and it's fed by old wires from the orginal K&T wiring. I wanted to fix this too. Looks like I could probably put one of those mounting blocks over the existing box.

Proby

MC offers little to no protection from screws or nails. MC is also hard to make bends so when it's running down your 3/4" wall it won't make a 90degree bend outside without a sweep, or else you might break the sheath or damage the conductors.

There's a good chance that the old fixture doesn't have a box behind it. Either way, you can put that siding block right over it, as you mentioned.

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Ptron

Good point.

So is it ok to fish down romex without any additional protection?

Proby

Yes, in many cases this is your only option.

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Anything fun is either illegal, immoral, or fattening.