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Electrical box depth and codes

I'm in the middle of tiling my backsplash and realize I'll need take some action to account for the additional depth of the electrical outlets and light switches. Apparently, when my house was built (mid 80s), the electrical boxes were installed flush with the wall studs and not protruding out 1/2" to account for the depth of the drywall. So the boxes are already recessed the depth of drywall and will have an additional 3/8" with the addition of the tile. So quite a gap from the box to the tile surface. I've seen the box extensions that are available, but the guy at the box store said they only fit inside of the "old work" style boxes and not boxes that were nailed in, which is what I have. Has anyone heard this before or had issues using the extensions on "new work" nailed boxes?
Another alternative I've seen is the accordian style exenders (not sure the name) that you put between the switch/outlet and the original box, to sort of shim the outlet firmly to the box. I'm just curious if these satisfy the electical code. Is the requirement for box extensions to fill the gap around the outlet or to ensure the outlet is securely mounted? If the latter, then seems the shims would be a good option.

Re: Electrical box depth and codes

The "spirit" of the code is that no flammable surfaces would be "visible" to the interior of the box. This is to protect from fire should there be arcing inside the electrical box. Gypsum is considered non-flammable; not sure how the paper facing is treated by the code.

I believe the code does allow for some variation in the box not being flush with the surface, but I don't remember how much it is. I would think the extensions should be fine, since the nail-on boxes tend to be larger than old-work boxes. It seems like I've seen plastic extensions sized for nail-on boxes in the local Home Despot, but I haven't really paid attention since I haven't ever needed one.

Re: Electrical box depth and codes

I have successfully used extensions on boxes that were not "old work" boxes a while back. If I remember correctly, in some cases I trimmed the depth of the extension to match the gap I needed to make up. I have also used the plastic washers when the gap was not large enough to necessitate the box extensions.

Re: Electrical box depth and codes

If the box is mounted with nails trough the side of the box, you can pull the nails and slid the box out flush and renail.

Blue RidgeParkway
Re: Electrical box depth and codes

How about a deeper "mud ring" Get one to make up the difference of the surfacing material your applying and the face of the box. Patch wall to within 1/8" then tile.

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