255 kW to Amps at 480V Three-Phase AC (US Industrial)
Exact current (Amps), real power (kW), apparent power (kVA), mechanical horsepower (HP), breaker rating, and conductor size for 255 kW on a 480V Three-Phase AC (US Industrial) circuit.
Line Current (0.85 PF)360.84 AAt 1.0 PF: 306.72 A
Active / Apparent Power255.0 kW300.0 kVA · 158.03 kVAR
Recommended Breaker500 A (NEC)400 A (IEC Nominal)
Recommended Copper Wire500 kcmilIEC Metric: 240 mm²
Engineering Breakdown for 255 kW at 480V
| Input Rating | 255 kW (480V Three-Phase AC (US Industrial)) |
| Amperage at 0.85 Power Factor (Industrial Motor/Transformer) | 360.84 Amps |
| Amperage at 1.00 Power Factor (Resistive Load) | 306.72 Amps |
| Real Power (kW / Watts) | 255.0 kW (255,000 W) |
| Apparent Power (kVA) & Reactive Power (kVAR) | 300.0 kVA / 158.03 kVAR |
| Equivalent Mechanical Horsepower (HP) | 341.96 HP |
| NEC 125% Continuous Circuit Breaker | 500 A |
| Minimum Copper Conductor (100 ft / 30 m, ≤3% Drop) | 500 kcmil (NEC) / 240 mm² (IEC) |
Frequently Asked Questions
How many amps is 255 kW at 480V (3-Phase)?
At 480V Three-Phase AC (US Industrial), 255 kW equals 360.84 Amps at an industrial power factor of 0.85 (or 306.72 Amps at unity power factor 1.0).
What size breaker and wire is needed for 255 kW at 480V?
For 360.84A continuous load, NEC requires a 125% rated breaker of 500A with 500 kcmil copper conductors, while IEC standard sizing uses a 400A breaker with 240 mm² copper cable.
Other Power Ratings & Voltages
5 kW at 480V (3P)10 kW at 480V (3P)15 kW at 480V (3P)20 kW at 480V (3P)25 kW at 480V (3P)30 kW at 480V (3P)45 kW at 480V (3P)50 kW at 480V (3P)75 kW at 480V (3P)100 kW at 480V (3P)150 kW at 480V (3P)200 kW at 480V (3P)250 kW at 480V (3P)500 kW at 480V (3P)255 kW at 120V Single-Phase AC255 kW at 208V Single-Phase AC255 kW at 230V Single-Phase AC (IEC)255 kW at 240V Single-Phase AC (NEC)255 kW at 208V Three-Phase AC255 kW at 230V Three-Phase AC255 kW at 400V Three-Phase AC (IEC Europe)255 kW at 415V Three-Phase AC (UK / AU)255 kW at 600V Three-Phase AC (Canada / Heavy)255 kW at 24V DC Direct Current255 kW at 48V DC Battery / Telecom Bus