Motor plugs and receptacles are UL approved for branch-circuit and motor-circuit disconnect switching. The devices have a shortcircuit make and withstand rating of 65,000 A (in fuse-protected circuits) and are rated to make and break under full load up to 60 hp and 200 A. During motor connection and disconnection, the plugs maintain a NFPA 70E-defined hazard-risk category of zero. Dead-front construction protects against access to live parts. The plugs and receptacles use silver nickel butt contacts; the silver nickel withstands arcs well and its conductivity in an oxidized state is reported to be more than 20 times higher than brass. The spring-loaded butt contacts ensure constant pressure. The contacts mate with a self-cleaning wiping action to remove deposits from surfaces.