4,500 Watts to Amps, How Many Amps Is 4,500 Watts?
4,500 Watts equals 37.50 amps at 120V or 18.75 amps at 240V. Common 4500W devices: Standard water heater element.
4,500 Watts Amps at Every Voltage
| Voltage | Single Phase | Three Phase |
|---|---|---|
| 120V | 37.50A | 21.65A |
| 208V | 21.63A | 12.49A |
| 240V | 18.75A | 10.83A |
| 277V | 16.25A | 9.38A |
| 480V | 9.38A | 5.41A |
The Formula
Single Phase: Amps = Watts ÷ Volts. For 4,500 Watts at 120V: 4500 ÷ 120 = 37.50A.
Three Phase: Amps = Watts ÷ (Volts × 1.732). For 4,500 Watts at 240V 3-phase: 4500 ÷ (240 × 1.732) = 10.83A.
With power factor: Amps = Watts ÷ (Volts × PF). A PF of 0.8 increases the current draw by 25%.
Wire and Breaker for 4,500 Watts at 120V
At 120V, 4,500 Watts draws 37.5A. Recommended: 8 AWG copper wire with a 40A breaker per NEC 310.16. For continuous loads (3+ hours), apply 125% rule. Use our Wire Size Calculator for exact sizing.
Common 4500W Devices
Standard water heater element. Always check the device nameplate for exact wattage, rated watts may differ from actual consumption.
Disclaimer: Calculations are for reference. Verify with device nameplate. Consult a licensed electrician for installations.