I current have plastic wall boxes. I need to connect to a MC conduit, which connects to an metal handy box with an receptacle. (NM to receptacle is not appropriate in this case).
I also have another 2 gang plastic wall box which needs to be connect to a FMC conduit attached to a cooktop. Can I use a two gang extension ring with knockouts?
Is it up to connect to install a metal extension ring with knockouts over a plastic wall box, as long as I put in a metal grounding click with wire, and join that wire to the other electrical ground conductors?
Best Answer
There are extension rings that fit over a standard single gang ring
Like any metal box, you'd have to bond the box to the EGC (green / bare wire) with a grounding screw or clip.
It will work just as shown in the photo for a single gang ring. I learned in a comment below, you can rotate the box 90* and the four holes in the back of the box will line up for a double gang ring.