What Size Wire Do I Need For 100 Amp Service?
What Size Wire Do I Need For 100 Amp Service? The cable must have a wire gauge sufficient to the amperage of the subpanel—a 100-amp subpanel requires #4 copper wires or, more commonly, #2 aluminum wires, for example. What size copper wire do I need for 100 amp service? SERVICE ENTRANCE CONDUCTORS SIZE AND RATING