Is chase nipple (+ bonding bush) proper way to mate RMC w/ sub-pa
It seems that die-cast wet-location j-boxes have deep threaded channels--at least on the top and bottom--with nicely rounded entries, such that no bushing is required, just thread, say a 6" RIGID nipple, right into it, apply silicone sealant, done on that end...
But when bringing the other end of that RMC nipple into the knockout of a sheet-metal box, I'm guessing a simple pair of locknuts (inside/outside) is not adequate, as wires would be exposed to edges of nipple/conduit. I'm thinking put a chase nipple inside box, then (female) coupler to mate with the 6" nipple, yes/no/that's the only way/are you crazy? ;')
Also, are one or more BONDING bushings involved, to maintain GND? Wanna get it right-eous.
Thanks in advance, best practices always.