IMC vs. GRC for Service Masts | Steel Tube Institute
GRC is a common industry acronym used for galvanized rigid conduit. GRC is the same product as UL-6 electrical rigid metal conduit — steel (ERMC-S) and rigid metal conduit (RMC) covered in NEC Article 344, which also covers aluminum RMC, stainless RMC and brass RMC. IMC is covered in Article 342 and is a steel galvanized conduit just like GRC ...