Look at your equipment name plate for amps. / volts. This is your power consumption. The resistance of the wire from the service panel to the receptacle or disconnect is virtually zero. The resistance IS from the electric utilization device. Most of these questions and answers on here prove you should be seeking out a licensed electrician. There is way too much use of rule-of-thumb circuit calculation going on. I love you guys but many answers are misguided, well meaning but still misguided. ,,,,,,,,,,Peace