Heavy Duty Direct Burial Ground Clamp w/ Lay-In Feature for 0.5-1in. Pipe The ultimate ground clamp for large ground wires. This incredible ground clamp can handle just about any size ground wire and just about any application. The lay-in feature provides for the ultimate in flexibility. UL Listed for direct burial in earth and concrete, it can be used with rebar, water pipe, copper tubing and ground rods up to 1 inch in diameter. cULus Listed 467 Grounding and Bonding. Silicone Bronze Screws conveniently pre-assembled.