What would be the voltage drop in an electrical circuit of the current draw was 65 amps and the circuit was 750 feet long with No. 6 TW conductor?

#6 copper wire has a resistance of 0.3951 ohms per 1000 ft (from wire tables). A 750 ft circuit contains 1500 ft of wire so the resistance is 0.5926 ohms. With 65 amps flowing the voltage drop is 38.5 volts.

The power lost in the cable is 2½ kW.