How Many Amps Is 20 kW at 480V?
20 kilowatts at 480V works out to roughly 28.3 amps on AC three-phase at PF 0.85. That is typical for commercial HVAC, industrial motors, rooftop units, and three-phase panel loads. See the DC and alternate-phase numbers below for other circuit types.
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 28.3A on AC three-phase at 480V, the load sits in the bracket between a 30A standard size (non-continuous) and the next size up that covers a continuous load under 210.19(A) (around 40A). 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
20 kW costs $3.40/hour at $0.17/kWh (rates last reviewed April 2026). See breakdown.
Power Factor Reference (AC three-phase)
How the line current for 20 kW at 480V 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 | 20 kW at 480V (AC three-phase) |
|---|---|---|
| Resistive (heaters, incandescent) | 1 | 24.06 A |
| Fluorescent lamps | 0.95 | 25.32 A |
| LED lighting | 0.9 | 26.73 A |
| Synchronous motors | 0.9 | 26.73 A |
| Typical mixed loads | 0.85 | 28.3 A |
| Induction motors (full load) | 0.8 | 30.07 A |
| Computers (without PFC) | 0.65 | 37.01 A |
| Induction motors (no load) | 0.35 | 68.74 A |
AC Conversion Comparison
On DC, 20kW at 480V draws 41.67A. AC single-phase at PF 0.85 pulls 49.02A because reactive current is added on top of the real power. Three-phase at the same voltage needs only 28.3A per line since the same 20kW is shared across three conductors instead of one.
| Circuit Type | Formula | Result |
|---|---|---|
| DC | 20,001 ÷ 480 | 41.67 A |
| AC Single Phase (PF 0.85) | 20,001 ÷ (0.85 × 480) | 49.02 A |
| AC Three Phase (PF 0.85) | 20,001 ÷ (1.732 × 0.85 × 480) | 28.3 A |
Other kW Values at 480V
| kW | AC 3-Phase per line, PF 0.85 | AC 1-Phase PF 0.85 |
|---|---|---|
| 3.5 kW | 4.95 A | 8.58 A |
| 4 kW | 5.66 A | 9.8 A |
| 5 kW | 7.08 A | 12.25 A |
| 6 kW | 8.49 A | 14.71 A |
| 7.5 kW | 10.61 A | 18.38 A |
| 8 kW | 11.32 A | 19.61 A |
| 10 kW | 14.15 A | 24.51 A |
| 12 kW | 16.98 A | 29.41 A |
| 15 kW | 21.23 A | 36.76 A |
| 18 kW | 25.47 A | 44.12 A |
| 20 kW | 28.3 A | 49.02 A |
| 22 kW | 31.13 A | 53.92 A |
| 25 kW | 35.38 A | 61.27 A |
| 30 kW | 42.45 A | 73.53 A |
| 35 kW | 49.53 A | 85.78 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.