Excelene 1/0 Welding Cable

[Flipper245]

Copper is essentially immune to corrosion. It behaves like a noble metal in most underground environments because of the naturally protective film that forms on the metal's surface. If this film, which often consists of reddish-brown cuprous oxide (Cu 20), is destroyed and cannot be repaired, copper will corrode.
copper oxidizes

aluminum corrodes. KMSL

Yup. I have some monster cable 4gauge that I peeled the insulation back and the outer layer of the strands were all green. So it corroded even though protected under its insulation. It must have been really old. Also I weighed 3 different copper cables. Knu, sky high and clarion. They all looked the same width and were weighed with the insulation off. The sky and knu were almost the same but the clarion was 1/3 the weight. That was really weird because it was made to imitate copper but obviously wasn't.