I have to install several electrical boxes for outlets, switches, and fixtures before installing some drywall. The boxes I have look like this:

enter image description here

The distance between the front of the mounting flange and the front of the box is about 7/16", but of course I'm going to use 1/2" drywall. So two questions:

  1. The box will end up sunken into the wall by 1/16" or so...will that matter?

  2. The flange itself is about 1/16" thick...will this make a bump or other problem under the drywall?

The place where these boxes are going is just wide enough for a 2-gang box to fit (I need to use some 2-gang boxes too, have ones like in the pic with the same mounting flange), so this kind of box is going to make things a lot easier than using the kind with the two nails since there's no way I could get a hammer in there to drive the nails. I could drive screws through the sides of the boxes into the studs, but I always find it hard to keep the boxes at the proper depth when I do that.

  • 1
    This question might be useful. As a side note, according to NEC 2008 314.43 you can not have exposed screw/nail heads inside a non-metallic box. This means you can not "drive screws through the sides of the boxes into the studs", if you are using non-metallic boxes.
    – Tester101
    Commented Oct 15, 2012 at 12:37

2 Answers 2


The 1/16" difference is not a problem. You are allowed up to 1/4" difference. The slight recess is much preferable to the box edge standing proud. Since nothing ever lines up precisely at this level of construction, better to err a little low than a little high.

The flange thickness is also not a problem. It will push the wallboard outwards a bit, but the resulting bulge will occur over a substantial distance, so it will not be discernible to the naked eye. It's similar to the slight bulge when the ends of wallboards are butted on ceilings and then taped over. There is an obvious bulge if you place a straight edge on it. But once everything is finished, an unaided eye cannot see it except with unusually oblique lighting.

These sort of boxes are a great solution to tight installations.


Personally I hate the blue plastic electrical boxes. I always use metal boxes because with a plain sided box it is very easy to drill some extra holes in the side of the box to secure it to the stud with some decent pan head sheet metal screws.

You really do want the electrical box to NOT extend out beyond the front surface of the drywall. A small recess allows for the thickness of the mounting ears of the switch or outlet. It also allows the cover plate to snug down against the wall surface instead of riding up on the receptacle/switch and leaving a gap between the cover and the wall surface.

  • 2
    I believe per code that the box is supposed to be within 1/4" of being flush with the drywall - so if you are using 1/2" drywall, and the box was flush with the rear of the drywall, it would not be compliant. Flush or 1/4" back is OK though. I think @Tester101 referenced this in a previous post, need to dig it up...
    – Steven
    Commented Oct 15, 2012 at 17:03

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