Say you have a junction box whose face is recessed significantly into the wall. For instance, if the face of the junction box is actually at the back of the drywall or perhaps 1/2" too deep.

Is it required to use a box extension in a case like this? Mechanically it would be possible just to use longer screws to attach the device - but would that violate code or cause some other problem?


  • Going to add this because I didn't know about them for the longest time... for boxes that are not extremely recessed, you can get a caterpillar to fill in the gap between the outlet and the recessed box.
    – JPhi1618
    Sep 10, 2019 at 19:41

1 Answer 1



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.

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