pecos busbar connectors

I can get aluminum or copper busbar. You suggest aluminum. Wouldn’t copper be better since it has higher conductivity?

Turns out that overall conductivity only scales as the square root of material conductivity because busbar is much thicker than the skin depth. This means that copper has almost no conductivity advantage. Offsetting this very small advantage are a few unfortunate properties of copper. Copper catalyzes oxidation of dielectric oil. Copper sulfide is a conductive compound that forms when copper reacts with sulfur in oil or air and tends to electromigrate and cause breakdown. And, most obviously, copper is much heavier and more expensive than aluminum.