Galvanized Rigid Steel Conduit (GRC, RMC) is the heaviest weight and thickest wall of electrical conduits. Allied Tube & Conduit®’s Galvanized Rigid Steel Conduit is hot-dip galvanized for corrosion resistance and is considered non-combustible. Galvanized Rigid Steel Conduit (GRC, RMC) can be used indoors, outdoors, underground, concealed or exposed.