How do I place electrical outlets in a non bearing wall with 2x4 sideways

Question

I am splitting a very large bedroom into two small ones. The minimum bedroom width is 7 feet. To accomplish that I have to build the dividing wall orienting the 2x4 studs so that the wide surface faces outward. This thin wall should have two electrical outlets. I was thinking to cut/remove the electric box bottom and make a hole on one of the sides and use a knockout non-metallic push-in connector to compensate for the electric box missing bottom.

Is there a better way to pass the electrical inspection?

Answer 1

Never modify plastic boxes, they are not designed to survive modification.

I use steel boxes, and this here is the most commonly used box. Note how it is 1-1/2" deep. Also available with flanges for mounting on 2x4's etc. So-called 3/8" cable clamps go in the smaller knockouts to hold Romex. They also make box variations with built in Romex clamps and fewer or no knockouts.

On top of that goes this "mud ring" to bring a 1-gang opening through 1/2" drywall. Giving about 26 total cubic inches. The mud ring is also available in 2-gang, though GFCI/AFCI will be a tight fit in the 2-gang version.

Note that with steel boxes, you are required to bring cable ground wires to the steel box FIRST. NEC 250.148. The box must remain grounded even if the switch or receptacle is totally removed.

How do you get grounds to the switch, then? Magically. The switch picks up ground via its mounting screws, and that's it. NEC 404.9(B). How about receptacles? If the receptacle is identified as "Self-Grounding" NEC 250.146(B), and the $3 "spec grade" receptacles are so identified, then it does the same trick. That's a real time-saver, since you now have 1 less wire to wrestle.

Your wires will be within 2" of the finished wall surface at all times, so you will need nail plates in a lot more places. Consider using EMT metal conduit to fully enclose the wires, as this provides nail plate protection inherently. Then use THHN individual wires.

Answer 2

Cutting apart a box is not going to go well. You have a couple of options.

• Regular Boxes

There are metal boxes that are nominally 1.5" deep, which matches the depth of a sideways 2x4 (1.5" x 3.5"). And actually, you have up to 2" to work with because you have the 1/2" drywall thickness as well. So there are boxes you can get which will fit just fine. The second part of this is, of course, the receptacles. I have one in front of me which is just about 1" thick, so a 1.5" box will do just fine. Not all receptacles will fit, and particularly GFCI, USB and other specialty receptacles need more space. But there are good quality standard duplex receptacles that will work just fine.

• Surface Mount Boxes

You can also use surface mount boxes. These are typically metal boxes designed for use with conduit on the outside of the wall, but they can also be fed with cable from inside the wall. More of an industrial look, but sometimes that is a necessary evil. And if you want to get a little fancier, you can use something like this Legrand Wiremold box from Home Depot:

which functions like any other metal box but has a more finished look.