I have a small section of a wall that has just like 1.5-2" of styrofoam insulation and then it will be drywall on top of it
This is because it is an old toilet drain that was put there close to the wall when there was no insulation

When they finished the basement the code did not allow the toilet to be too close to the wall so they did not put framing there (exterior wall, under grade)

I am installing a smart toilet there and I need a power plug behind it so I will have to put an outlet electrical box there (this is what I am thinking now). Is there a low profile outlet box that would fit in the 1.5-2"? If not what is the lowest profile I can get or what other solutions are available for such situations? (I do not want to make room for it in the cinder block)

  • 1
    Where do you live? Plug being where it is, you should have GFCI protection. You can buy toilets that sit back different amounts from the drain opening, although they can be expensive. You can likely also thicken the wall below the height of the tank. That said, 2" insulation + 1/2" drywall gives you boxes up to 2.5" deep, which shouldn't be hard to source.
    – K H
    May 8 at 15:57
  • 1
    A surface-mount box eliminates the problem of depth in the wall. GFCI protection is not a maybe, it's a must. Plenty of standard boxes at 1.5 inch depth. at least in steel.
    – Ecnerwal
    May 8 at 16:26
  • Yes that is what I wnded up ordering
    – MiniMe
    May 9 at 11:42

Easy as pie with metal boxes.

The problem is most people tend to go straight for plastic boxes (which kind of ignores the whole reason we have boxes; to ground out loose wires and contain arcing fires).

The standard 4x4 metal box is only 1-1/2" deep. They also make 1-gang boxes only 1-1/4" deep. These are the common cheap boxes, not a pricey specialty item.

A 4x4 box, you mount it flush to the studs and then use a "Mud Ring" the thickness of the drywall and the mud ring gives you a 1-gang or 2-gang opening. With a 1-gang box, you can mount it flush to the drywall, so you're going less than an inch into the insulation.


Carlon makes one that's 1.25" deep. Picture below is from HD -

enter image description here

I am not sure what the NEC or your local jurisdiction requires. A quick search indicates 1.5" may be the minimum depth. Someone with more knowledge of the code can probably provide better insight.

  • 1
    Note that you might need gfci protection, and that a gfci might not fit a really shallow box. If so, put a gfci upstream or at the breaker. May 8 at 15:59
  • 1
    That is already done thank you
    – MiniMe
    May 8 at 16:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.