I need to install an outlet in an existing 2x3 wall but can't figure out how to get enough box volume in this skinny wall. The studs are 2 5/8" with 7/8" of gypsum lath and plaster. I need 20.25 in3 of box volume to handle the 12/3 in and out and the device.
4x4 box with mud ring would give the volume, but how to set in as old work box with a single gang outlet? Using old work wings would bring the box flush with wall, but then faceplate won't cover if only trying to install one device.
Ganging together two single-gang old work boxes has the same problem of having a double gang exposed when I only need one.
The only thing I've come up with so far was to gang together two old work boxes, setting them behind the plaster, one covered with a faceplate, and the other with a box extender to bring it through the plaster.