Heavy is a QUAL word, wondering about the QUAN on that wire. I sure hope it is 4* or larger.(lower gauge #/ bigger wire) Was working on an old 70's Chevy. Some smarty pants(NOT) had "insulated" the end of the negative wire where it bolts onto the engine block!!! EEEEK!!!(They didn't think a WIRE from the battery should touch the iron of the engine block, so they insulated it with rubber gromets!) The car would crank but very slowly because the only ground path back to the battery was a "body ground" 10* wire from the Neg battery clamp to the fender. I guess the engine was grounding to the frame and body through the motor mounts? That little wire allowed the starter to crank over, but slowly, BUT as a PLUS, it got very HOT! It made an excellent branding iron across my fingers as I touched it! The insulation was virtually liquified by all those(Probably 300+) CCA's returning to the battery through a 10* wire bottleneck of resistance. (It was a little like grabbing the guts of a toaster!) *********** All "wire" is NOT equal! Stranded wire used in 110 Office/Industrial building applications, though "stranded", is using much larger strands that are high resistance in DC systems, like cars! Buy automotive wire at auto parts suppliers! If you find non automotive wire in your project's donor, repair/replace it before use! Solid copper house wire is even worse!(Yes, I've seen that too, very sad. Using "wire nuts" no less! This is how I got all this gray hair.)