What Is the Resistance and Power for 480V and 500A?

With 480 volts across a 0.96-ohm load, 500 amps flow and 240,000 watts are dissipated. These four values (voltage, current, resistance, and power) are the foundation of every electrical calculation on this site.

480V and 500A
0.96 Ω   |   240,000 W
Voltage (V)480 V
Current (I)500 A
Resistance (R)0.96 Ω
Power (P)240,000 W
0.96
240,000

Formulas & Step-by-Step

Resistance

R = V ÷ I

480 ÷ 500 = 0.96 Ω

Power

P = V × I

480 × 500 = 240,000 W

Verification (alternative formulas)

P = I² × R

500² × 0.96 = 250,000 × 0.96 = 240,000 W

P = V² ÷ R

480² ÷ 0.96 = 230,400 ÷ 0.96 = 240,000 W

Circuit Analysis

Heat Dissipation

This circuit dissipates 240,000 watts of power as heat. In a resistor, all electrical energy at steady state converts to thermal energy. The actual component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve rather than applying a blanket margin.

If You Change the Resistance

ResistanceCurrentPowerChange
0.48 Ω1,000 A480,000 WLower R = more current
0.72 Ω666.67 A320,000 WLower R = more current
0.96 Ω500 A240,000 WCurrent
1.44 Ω333.33 A160,000 WHigher R = less current
1.92 Ω250 A120,000 WHigher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 0.96Ω, here is how current and power scale with source voltage. This is a reference table, not a set of separate circuit scenarios: each row is the same resistor under a different applied voltage.

VoltageCurrent (at 0.96Ω)Power
5V5.21 A26.04 W
12V12.5 A150 W
24V25 A600 W
48V50 A2,400 W
120V125 A15,000 W
208V216.67 A45,066.67 W
230V239.58 A55,104.17 W
240V250 A60,000 W
480V500 A240,000 W

Frequently Asked Questions

R = V ÷ I = 480 ÷ 500 = 0.96 ohms.
All 240,000W is dissipated as heat in a pure resistor at steady state. The component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve.
V=IR, V=P/I, V=√(PR) | I=V/R, I=P/V, I=√(P/R) | R=V/I, R=V²/P, R=P/I² | P=VI, P=I²R, P=V²/R.
For purely resistive loads, yes. For reactive loads, use impedance (Z) instead of resistance (R). Z includes both resistance and reactance, and the V/I phase shift shows up in power factor.
Ohm's Law (V = IR) and the power equation (P = VI) connect all four. Given any two, you can calculate the other two.
This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.