Bi-metallic lugs are electrical cable lugs that are manufactured by using two different metals, copper and aluminum, which are combined by a solid-state welding or friction welding technique. The aluminum part is joined to aluminum conductors, and the copper part is joined to copper busbars or terminals. https://thefairlist.com/story11246058/copper-bonded-earthing-rods-a-reliable-foundation-for-electrical-safety