Amps, breaker and wire by voltage
| Voltage | Current | Breaker (continuous) | Copper wire |
|---|---|---|---|
| 120 V | 29.2 A | Use 240 V | – |
| 208 V | 16.8 A | 25 A | 10 AWG |
| 240 V | 14.6 A | 20 A | 12 AWG |
| 480 V 3-phase | 4.21 A | – | – |
Breaker sized at 125% for continuous loads (NEC 210.20). Motors and electronics draw more current than watts ÷ volts because of power factor.
Frequently asked questions
Can a 15 amp circuit handle 3,500 watts?
No. A 15 A circuit at 120 V supplies at most 1,800 W. Use a 20 A circuit (up to 2,400 W) or a 240 V circuit.
How many amps is 3,500 watts at 12 volts?
292 A at 12 V DC, before inverter losses (about 324 A through a 90% efficient inverter).