How Many Amps Is 125 kW at 400V?
125 kW at 400V draws about 212.26 amps on an AC three-phase circuit at PF 0.85, typical for commercial HVAC, industrial motors, rooftop units, and three-phase panel loads. Actual current varies with equipment power factor and duty cycle.
Use this citation when referencing this page.
Formulas
DC: kW to Amps
I(A) = 1000 × P(kW) ÷ V(V)
AC Single Phase (PF = 0.85)
I(A) = 1000 × P(kW) ÷ (PF × V(V))
AC Three Phase (PF = 0.85)
I(A) = 1000 × P(kW) ÷ (√3 × PF × VL-L), where VL-L is the line-to-line voltage
Equipment & Circuit Sizing
Breaker Sizing
Breaker ratings are in amps, not watts, so the real install answer depends on the equipment nameplate FLA, whether the load is continuous (NEC 210.19(A) sizes the conductor and OCP at 125% of a continuous load, equivalently 80% of breaker rating), conductor ampacity and temperature rating, ambient and bundling derates, and any motor or HVAC provisions (NEC 430 / 440). At roughly 212.26A on AC three-phase at 400V, the load sits in the bracket between a 225A standard size (non-continuous) and the next size up that covers a continuous load under 210.19(A) (around 300A). The actual install pick depends on whether the load is continuous and the factors above; a conversion page can't pick a single "right" breaker from the amp draw alone.
Energy Cost
125 kW costs $21.25/hour at $0.17/kWh (rates last reviewed April 2026). See breakdown.
Power Factor Reference (AC three-phase)
How the line current for 125 kW at 400V changes with load power factor, on the same AC three-phase circuit basis the rest of the page uses. DC has no power factor; PF 1.0 represents resistive AC loads.
| Load Type | PF | 125 kW at 400V (AC three-phase) |
|---|---|---|
| Resistive (heaters, incandescent) | 1 | 180.42 A |
| Fluorescent lamps | 0.95 | 189.92 A |
| LED lighting | 0.9 | 200.47 A |
| Synchronous motors | 0.9 | 200.47 A |
| Typical mixed loads | 0.85 | 212.26 A |
| Induction motors (full load) | 0.8 | 225.53 A |
| Computers (without PFC) | 0.65 | 277.57 A |
| Induction motors (no load) | 0.35 | 515.49 A |
AC Conversion Comparison
On DC, 125kW at 400V draws 312.5A. AC single-phase at PF 0.85 pulls 367.65A because reactive current is added on top of the real power. Three-phase at the same voltage needs only 212.26A per line since the same 125kW is shared across three conductors instead of one.
| Circuit Type | Formula | Result |
|---|---|---|
| DC | 125,000 ÷ 400 | 312.5 A |
| AC Single Phase (PF 0.85) | 125,000 ÷ (0.85 × 400) | 367.65 A |
| AC Three Phase (PF 0.85) | 125,000 ÷ (1.732 × 0.85 × 400) | 212.26 A |
Other kW Values at 400V
| kW | AC 3-Phase per line, PF 0.85 | AC 1-Phase PF 0.85 |
|---|---|---|
| 15 kW | 25.47 A | 44.12 A |
| 18 kW | 30.57 A | 52.94 A |
| 20 kW | 33.96 A | 58.82 A |
| 22 kW | 37.36 A | 64.71 A |
| 25 kW | 42.45 A | 73.53 A |
| 30 kW | 50.94 A | 88.24 A |
| 35 kW | 59.43 A | 102.94 A |
| 40 kW | 67.92 A | 117.65 A |
| 50 kW | 84.9 A | 147.06 A |
| 60 kW | 101.89 A | 176.47 A |
| 75 kW | 127.36 A | 220.59 A |
| 100 kW | 169.81 A | 294.12 A |
| 125 kW | 212.26 A | 367.65 A |
| 150 kW | 254.71 A | 441.18 A |
| 200 kW | 339.62 A | 588.24 A |
Same kW, Other Voltages
Each destination page leads with the interpretation most common for that voltage, so the amps shown below use the same basis as the page you'd land on: single-phase for residential voltages, three-phase for commercial/industrial panel voltages, DC for low-voltage.