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Do electrical boxes have to be flush to the finished surface? Can they recess any depth into the wall by as much as 1/8" or 1/4"?

Edit: I appreciate everyone offering alternative solutions to making a non-flush, already-installed box flush to the finish, but remember that I am looking for an objective answer regarding whether or not the box has to be flush to the wall. This is new work, so if I can get by with having it recess into the wall by 1/8" or 1/4" then I will do so. Otherwise, I will have to alter my plans.

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They make box extenders (an example is depicted below) that can be used to extend boxes to meet the finished surface.

a non-metallic box extender of the telescopic type

The 2014 NEC says...

ARTICLE 314

Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures

314.20 In Wall or Ceiling. In walls or ceilings with a surface of concrete, tile, gypsum, plaster, or other noncombustible material, boxes employing a flush-type cover or faceplate shall be installed so that the front edge of the box, plaster ring, extension ring, or listed extender will not be set back of the finished surface more than 6 mm (1⁄4 in.). In walls and ceilings constructed of wood or other combustible surface material, boxes, plaster rings, extension rings, or listed extenders shall be flush with the finished surface or project therefrom.

This might also be relevant.

406.4 Receptacle Mounting. Receptacles shall be mounted in boxes or assemblies designed for the purpose, and such boxes or assemblies shall be securely fastened in place unless otherwise permitted elsewhere in this Code.

(A) Boxes That Are Set Back. Receptacles mounted in boxes that are set back from the finished surface as permitted in 314.20 shall be installed such that the mounting yoke or strap of the receptacle is held rigidly at the finished surface.

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  • My issue is that I need to install new work boxes so that they extend 1 1/4" beyond the stud. This way, when my second layer of 5/8" drywall goes up, it will be flush. I don't have enough depth with the boxes I am using to go out 1 1/4", so I am wondering if I can extend it 1 1/8" instead. This means the box will be recessed into the wall by 1/8" and I am wondering if that is okay. I don't want to install a box extender for just 1/8". That would be more for old work installs, I'd think. – oscilatingcretin Jan 22 '12 at 18:27
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    @oscilatingcretin I'll look for NEC reference later, but my understanding is that the box must extend to the finish level. – Tester101 Jan 22 '12 at 18:29
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    I'm not certain on code; most of the boxes I've seen tend to be somewhere between flush and 1/4" recessed, just by the nature of construction. Boxes are flexible, positioning is imprecise, and wood can have a bit of warp. The problem I've found with boxes being too far back is getting screws to reach the mounting holes in order to install outlets, switches, faceplates... Box extenders help with this as well. – Scivitri Jan 22 '12 at 19:01
  • Scivitri - That's what I've noticed about pre-existing boxes in my house. Still, I'd rather know for sure rather than follow the previous guys' example in the event that they did it wrong. Tester, your help is appreciated. – oscilatingcretin Jan 23 '12 at 14:15
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    @oscilatingcretin Found the NEC article, see edit. – Tester101 Jan 23 '12 at 17:50
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Since you say new construction you can get adjustable boxes if not from a big DIY box store then you can get them from an electrical wholesaler.

Adjustable box

If you use the box extender make sure what you buy has a UL on it, or whatever country you live in stamp of approval.

Here's the spec sheet on the adjustable box. Here.

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  • I have a few of these from Carlon, but I like this design. These are more expensive than the $0.75 nail-in boxes I picked up, so I'd rather set the nail-in box at just the right position rather than install a more expensive box just so I can adjust it later. – oscilatingcretin Jan 23 '12 at 14:18
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    @oscilatingcretin - People that use these use them more in kitchens and bathrooms where they are not sure of the depth of the tile or things like that. – lqlarry Jan 25 '12 at 4:41
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    I wondered the same thing before I set out to build my office/media room in my basement. I too was going to install double DW and needed boxes that extended 1-1/4" out. I opted for the adjustable ones, since they are very secure and solid. They attached securely with 2-screws into the front of the stud and 2 into the side. They were more expensive, but proved to be the best solution and one I was happy with. They make these for class 2 wiring also, but alas, I can't find anyone but the supplier that stocks them. Not even on the net. And you can't buy direct from the manufacturer either. :( – user20509 Mar 17 '14 at 20:12
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    I find that the material cost of the adjustable boxes is significantly cheaper than the labor cost of getting the fixed boxes lined up correctly. – Tim Sparkles Aug 21 '18 at 19:47
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All you have to do is use a cheap plastic nail on box, cut the plastic off that holds the nail, and fasten it with 2 drywall screws from the inside of the box.

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    Are you allowed to have screws exposed inside the box? – BMitch♦ Jul 22 '12 at 13:25
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    That would be pure hackery, and is not allowed by code. – kreemoweet Oct 13 '12 at 3:24

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