I don't know much about conductivity or that temperature melting point crap in your equation, but if Copper melts, wouldn't it make sense to build it using an equally conductive but much stronger material? I do know that copper isn't exactly that durable, whereas something like steel may be able to conduct the same amount of Amps or Ohms or Watts or whatever. Just a thought, not really sure, just thought I'd throw it out there.