Exterior wall box options

Electromatic

Member
Location
Virginia
I need to rough-in boxes for exterior lights, receptacles, door access systems, etc. From the outside edge of the metal studs to the finished exterior is about 3". Any advice on box/mud-ring mounting options?
I've considered a 2-1/8" deep 4-square with about a 3/4" mud ring mounted to the outside of the stud, but then I'd have to offset the conduit from the box back into the wall through the insulation, etc. To avoid that, I could mount the boxes in the wall then use a deep extension ring and a mud ring, but that seems like it would get pretty flimsy.
Ideas?
thanks in advance ext wall.jpg
 

kwired

Electron manager
Location
NE Nebraska
2.5 inch deep masonry type box with about 1/4 - 3/8 spacer of some sort behind it?

4x4 x 2.125 box with 3/4 mud rings? 7/8 mud ring probably little too much, but you can be recessed up to 1/4 inch in non combustible finish.
 

Electromatic

Member
Location
Virginia
2-1/8 box with 3/4 ring gets me close to the finished wall, but I'll have to offset my conduit back into the stud bay. Some will require 1" pipe. In addition to our having to offset, others will have to notch the foam insulation and inner sheathing around our pipe.
 

kwired

Electron manager
Location
NE Nebraska
What is depth of stud bay? What size raceway?

With 1/2 EMT you are likely able to fit a 90 degree bend behind the box if you only go with 1.5 inch deep box and find a way to space it, 3/4 EMT is a maybe if studs are at least 2x6 dimensions.
 

RAKocher

Member
Location
SE Pennsylvania
A 2-1/8" deep box w/ a 1-1/2" extension and a 3/8" or 1/2" plaster ring at least puts the KO's in the bay and is a little friendlier to whoever has to get back in there.
Am I the only one who's ever wondered about 314.29 and plaster rings?
 

RAKocher

Member
Location
SE Pennsylvania
I never did, what's your thinking?
I lost that argument many years ago, but the first time that I tried to fish another cable into a 4" box w/ a s/g plaster ring I can remember thinking, "How is this legal?" And the looks of that 3-1/2" deep plaster ring brought that memory back. Plaster rings can be nice for new work but not so much for old work.
 

oldsparky52

Senior Member
I lost that argument many years ago, but the first time that I tried to fish another cable into a 4" box w/ a s/g plaster ring I can remember thinking, "How is this legal?" And the looks of that 3-1/2" deep plaster ring brought that memory back. Plaster rings can be nice for new work but not so much for old work.
Is this an old work job?

I don't know how you would install a plaster ring in an old work job w/out cutting up some wall surface.
 

RAKocher

Member
Location
SE Pennsylvania
Is this an old work job?

I don't know how you would install a plaster ring in an old work job w/out cutting up some wall surface.
I'm not referring to any work I'm doing at the moment, I'm just expressing my opinion that because plaster rings block some access to the top, bottom and sides of 4" boxes that 314.29 may apply.
And, especially, if that 3-1/2" deep plaster ring or similar was used how would someone work in that device box years later? My fingers aren't even 3-1/2" long.
 

oldsparky52

Senior Member
I'm not referring to any work I'm doing at the moment, I'm just expressing my opinion that because plaster rings block some access to the top, bottom and sides of 4" boxes that 314.29 may apply.
And, especially, if that 3-1/2" deep plaster ring or similar was used how would someone work in that device box years later? My fingers aren't even 3-1/2" long.
IMO, 314.29 does not apply to plaster rings unless covered by a wall. (but ... I've been wrong before, many times)

Because of the difficulty in reaching in that box, I surely would not want to feed through that box, I'd want it to be a dead end.
 

kwired

Electron manager
Location
NE Nebraska
I lost that argument many years ago, but the first time that I tried to fish another cable into a 4" box w/ a s/g plaster ring I can remember thinking, "How is this legal?" And the looks of that 3-1/2" deep plaster ring brought that memory back. Plaster rings can be nice for new work but not so much for old work.
Can be a challenge, but nothing prohibits it. Any conductors with free ends in that box must be able to extend at least 4 inches past the opening, conductors that pass through may be nearly impossible to access in some cases but are still legal.
 

Electromatic

Member
Location
Virginia
I ended up using a bracket and a deep 4"square in the stud bay with the box flush to the outside of the stud, then a 2-1/8" deep extension ring with a 1/2" mud ring. They changed the insulation down from 1-1/4" to 1". It seemed reasonably sturdy. I wouldn't have wanted to deal with a 3" mud ring either, and I've got pretty nimble fingers.
Thanks for the thoughts.
 
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