40 kVA 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 40 kVA on a 120V Single-Phase AC circuit.
Line Current (0.85 PF)333.33 AAt 1.0 PF: 333.33 A
Active / Apparent Power34.0 kW40.0 kVA · 21.07 kVAR
Recommended Breaker450 A (NEC)350 A (IEC Nominal)
Recommended Copper Wire400 kcmilIEC Metric: 185 mm²
Engineering Breakdown for 40 kVA at 120V
| Input Rating | 40 kVA (120V Single-Phase AC) |
| Amperage at 0.85 Power Factor (Industrial Motor/Transformer) | 333.33 Amps |
| Amperage at 1.00 Power Factor (Resistive Load) | 333.33 Amps |
| Real Power (kW / Watts) | 34.0 kW (34,000 W) |
| Apparent Power (kVA) & Reactive Power (kVAR) | 40.0 kVA / 21.07 kVAR |
| Equivalent Mechanical Horsepower (HP) | 45.59 HP |
| NEC 125% Continuous Circuit Breaker | 450 A |
| Minimum Copper Conductor (100 ft / 30 m, ≤3% Drop) | 400 kcmil (NEC) / 185 mm² (IEC) |
Frequently Asked Questions
How many amps is 40 kVA at 120V (1-Phase)?
At 120V Single-Phase AC, 40 kVA equals 333.33 Amps at an industrial power factor of 0.85 (or 333.33 Amps at unity power factor 1.0).
What size breaker and wire is needed for 40 kVA at 120V?
For 333.33A continuous load, NEC requires a 125% rated breaker of 450A with 400 kcmil copper conductors, while IEC standard sizing uses a 350A breaker with 185 mm² copper cable.
Other Power Ratings & Voltages
5 kVA at 120V (1P)10 kVA at 120V (1P)15 kVA at 120V (1P)20 kVA at 120V (1P)25 kVA at 120V (1P)30 kVA at 120V (1P)45 kVA at 120V (1P)50 kVA at 120V (1P)75 kVA at 120V (1P)100 kVA at 120V (1P)150 kVA at 120V (1P)200 kVA at 120V (1P)250 kVA at 120V (1P)500 kVA at 120V (1P)40 kVA at 208V Single-Phase AC40 kVA at 230V Single-Phase AC (IEC)40 kVA at 240V Single-Phase AC (NEC)40 kVA at 208V Three-Phase AC40 kVA at 230V Three-Phase AC40 kVA at 400V Three-Phase AC (IEC Europe)40 kVA at 415V Three-Phase AC (UK / AU)40 kVA at 480V Three-Phase AC (US Industrial)40 kVA at 600V Three-Phase AC (Canada / Heavy)40 kVA at 24V DC Direct Current40 kVA at 48V DC Battery / Telecom Bus