400 kW to Amps at 120V Single-Phase AC
Exact current (Amps), real power (kW), apparent power (kVA), mechanical horsepower (HP), breaker rating, and conductor size for 400 kW on a 120V Single-Phase AC circuit.
Line Current (0.85 PF)3921.57 AAt 1.0 PF: 3333.33 A
Active / Apparent Power400.0 kW470.59 kVA · 247.9 kVAR
Recommended Breaker5000 A (NEC)4000 A (IEC Nominal)
Recommended Copper Wire8× 1000 kcmil (Parallel)IEC Metric: 7× 400 mm²
Engineering Breakdown for 400 kW at 120V
| Input Rating | 400 kW (120V Single-Phase AC) |
| Amperage at 0.85 Power Factor (Industrial Motor/Transformer) | 3921.57 Amps |
| Amperage at 1.00 Power Factor (Resistive Load) | 3333.33 Amps |
| Real Power (kW / Watts) | 400.0 kW (400,000 W) |
| Apparent Power (kVA) & Reactive Power (kVAR) | 470.59 kVA / 247.9 kVAR |
| Equivalent Mechanical Horsepower (HP) | 536.41 HP |
| NEC 125% Continuous Circuit Breaker | 5000 A |
| Minimum Copper Conductor (100 ft / 30 m, ≤3% Drop) | 8× 1000 kcmil (Parallel) (NEC) / 7× 400 mm² (IEC) |
Frequently Asked Questions
How many amps is 400 kW at 120V (1-Phase)?
At 120V Single-Phase AC, 400 kW equals 3921.57 Amps at an industrial power factor of 0.85 (or 3333.33 Amps at unity power factor 1.0).
What size breaker and wire is needed for 400 kW at 120V?
For 3921.57A continuous load, NEC requires a 125% rated breaker of 5000A with 8× 1000 kcmil (Parallel) copper conductors, while IEC standard sizing uses a 4000A breaker with 7× 400 mm² copper cable.
Other Power Ratings & Voltages
5 kW at 120V (1P)10 kW at 120V (1P)15 kW at 120V (1P)20 kW at 120V (1P)25 kW at 120V (1P)30 kW at 120V (1P)45 kW at 120V (1P)50 kW at 120V (1P)75 kW at 120V (1P)100 kW at 120V (1P)150 kW at 120V (1P)200 kW at 120V (1P)250 kW at 120V (1P)500 kW at 120V (1P)400 kW at 208V Single-Phase AC400 kW at 230V Single-Phase AC (IEC)400 kW at 240V Single-Phase AC (NEC)400 kW at 208V Three-Phase AC400 kW at 230V Three-Phase AC400 kW at 400V Three-Phase AC (IEC Europe)400 kW at 415V Three-Phase AC (UK / AU)400 kW at 480V Three-Phase AC (US Industrial)400 kW at 600V Three-Phase AC (Canada / Heavy)400 kW at 24V DC Direct Current400 kW at 48V DC Battery / Telecom Bus