Recently an inspector required the 120 volt circuit to a intrinsically safe relay, to be GFCI protected. He said because the relay isn't UL listed. Can anyone explain this resoning. Thanks for the help.
Possibly may be a requirement in the UL listing for IS systems, there is a UL standard 1394 or similar. Use of a GFCI is allowed in UL 508 Industrial Motor Control Standard for non listed equipment.