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?