The answer depends on the current draw and the length that the wires need to be (how far the hot tub is located from the breaker box). 6 gauge would likely be fine if you are connecting to an...
Your question really depends on your local codes and what exactly you are wiring. With out know your local codes, all I can suggest is that you either do some research for your city, county, and...
Copper is an excellent conductor, ductile (can be drawn easily), and reasonably economical. For bare conductors, copper oxidises and the oxide coating prevents further corrosion. While it is heavier...