How to fix broken electrical box w/o drywall work

Question

How do you fix a broken electrical box like this? It holds the heated floor control panel. The box just falls out - you can see a broken plastic piece at the top. Ideally I would like to avoid doing drywall work if at all possible.

Answer 1

Apparently you need a new "old work box" where the bit on the screw that grabs the inside of the wall is not broken, as the one on the screw visible in this picture is.

If the box is exactly the same you may be able to transfer that bit only from the new to the old box. I don't think you can find only those bits to buy, but I could be wrong about that.

Here's a picture, with the bit sticking up (and the corresponding one on the bottom down.) They fold down flat against the box so you can put it in the hole, and then rotate outwards as you tighten the screw. If you loosen the screw before pulling the box out of the wall they will fold back down, rather than breaking off.

Image source, no endorsement implied

Answer 2

While those boxes are common and inexpensive enough that a tab swap would be my preferred approach, I've actually made a tab for a box like that in a pinch. I just folded some sheet metal around the screw and trimmed it to a suitable shape. The screw threads will hold if the fold is snug. Depending on the metal you have on hand you may need to double it over a time or two so it's rigid enough.

Of course, you could shave a bit of scrap plastic down and drill for the screw. It's not exactly a complicated gizmo. Just look at the one on the bottom as a pattern. The only critical aspect is the material around the screw, which has to fit in the slot.

Answer 3

As others have recommended, you can find those blue old work boxes readily available at big box stores. Buy one and swap out the blue tab. No need to swap the whole box. You want to use a regular screwdriver, not a screw gun. The reason those tabs break is because they are annoying to install, so installers use a screw gun and overtighten them. I often use a screw gun to run them in and out once before installing, then use a manual screwdriver once it is in the wall. Sometimes you have to use another thin tool or screw driver to keep them from flipping out of their slot as you tighten them.

Option two is to use old school "Madison clips". They are made of thin sheet metal:

Check youtubes for usage examples, e.g, https://www.youtube.com/watch?v=-pFnaQFAu40.

Answer 4

One option is to glue in the box with "Two part High Performance Wood Filler", this sets quickly once mixed and is very strong.

Fill all the gaps between the box and plasterboard. Then sand it back level with the plasterboard once set.