The best metals for electrical wire cables are Silver, Copper, and Aluminum. Silver is the best but also very expensive and would not be commercially viable for installing domestic solar systems. Copper is the best alternative and much more affordable than Silver. Use a solar cable that carries the Underwriters Laboratory (UL) markings defining it. As a rule, always go for a heavier gauge wire. The initial investment will be higher, but the payback will be in system efficiency. An inner protective coating of the copper wire strands affords an additional layer of protection and flexibility. It prevents moisture ingress and ensures that the bundle of stranded wire is compact. An outer Silicon-b. No,THNN wire has a much larger insulating layer on the conductor, which isn't needed for the lower voltage of a solar panel application. That insulation would block too much electrical current flow for it to be helpful in a solar panel set. THHN wire has a small insulating layer on the conductor, and that insulation is fine for lower voltage solar. No. The ACSR wire has aluminum conductors, but those conductors are much thicker to make up for the lack of electrical current flow from an aluminum conductor compared to copper. You can do calculations as you would for THHN wire to ensure your wires have enough wattage capacity for your application (in this case, a solar panel system). The cables. No. For several reasons, mainly because all conductors have some resistance, so if you're wiring up your house with Romex (which has NM-B insulation), there will be too much electricity loss through heat generation, which could cause problems including fires if they get bad enough. Plus, the thin NM-B insulation isn't meant to withstand the heat of.
