Dual Rated Ground Clamps, Cable to Water Pipe, 1/0-14 AWG, 1/2-3/4-1 pipe, Al/Cu Rated. CMC® Dual Rated Ground Clamps are manufactured from high strength 6061-T6 aluminum alloy to insure both maximum strength and conductivity. They are dual rated for both copper and aluminum conductors and are electro tin plated to provide low contact resistance and protection against corrosion. They effectively ground copper or aluminum conductors to copper water pipe, galvanized pipe, or steel conduit.