Calculates active, apparent and reactive power for single-phase and three-phase systems with power factor cos φ.
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Amps to kW: table for 120 V, 230 V and 400 V
How much power can a circuit deliver? Real power for a purely resistive load (power factor cos φ = 1) and a typical motor load (cos φ = 0.85). North America uses 120 V, Europe and most other countries 230 V single-phase and 400 V three-phase.
Single-phase: P = V × I × cos φ
| Current | 120 V, cos φ = 1 | 230 V, cos φ = 1 | 230 V, cos φ = 0.85 |
|---|---|---|---|
| 6 A | 0.72 kW | 1.38 kW | 1.17 kW |
| 10 A | 1.20 kW | 2.30 kW | 1.96 kW |
| 13 A | 1.56 kW | 2.99 kW | 2.54 kW |
| 15 A | 1.80 kW | 3.45 kW | 2.93 kW |
| 16 A | 1.92 kW | 3.68 kW | 3.13 kW |
| 20 A | 2.40 kW | 4.60 kW | 3.91 kW |
| 25 A | 3.00 kW | 5.75 kW | 4.89 kW |
| 30 A | 3.60 kW | 6.90 kW | 5.87 kW |
| 32 A | 3.84 kW | 7.36 kW | 6.26 kW |
Three-phase 400 V: P = √3 × V × I × cos φ
| Current per line | cos φ = 1 | cos φ = 0.85 |
|---|---|---|
| 6 A | 4.2 kW | 3.5 kW |
| 10 A | 6.9 kW | 5.9 kW |
| 16 A | 11.1 kW | 9.4 kW |
| 20 A | 13.9 kW | 11.8 kW |
| 25 A | 17.3 kW | 14.7 kW |
| 32 A | 22.2 kW | 18.8 kW |
| 40 A | 27.7 kW | 23.6 kW |
| 50 A | 34.6 kW | 29.4 kW |
| 63 A | 43.6 kW | 37.1 kW |
Example: a 15 A / 120 V outlet delivers at most 1.8 kW, a 16 A / 230 V socket 3.68 kW. These are calculated values; cable size also depends on installation method and length.
