by stuartb3502 »
Wed Jan 01, 2020 10:26 am
Replying as you have no other replies yet. I think you're trying to solve the wrong problem. If you can't screw the socket into the wall box without tripping the circuit, you have a dangerous fault in the work that you've done.
Recommend solving that first (i.e. before you kill yourself or someone else or burn your house down) and then you may find that you can screw the faceplate on if that's all that's stopping you. If not, the wallbox is too mounted too deep - fix that in preference to filling.
I'm not an electrician, but I know that when I asked our electrician to mount some shaver sock faceplates on the surface of a cupboard back he refused. The back of the cupboard needed to be cut out and so that the faceplates could mate tightly to wallbox.
All the best.