20 Amp Cable Size at 250 Meters (415V Three-Phase (UK / Australia Industrial))
IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 20 A over 250 m (820.2 ft).
Copper Cable (≤3% Drop)16 mm²Drop: 11.58V (2.79%)
Aluminum Cable (≤3% Drop)25 mm²Drop: 12.23V (2.95%)
Voltage at Load403.4 VLine Loss: 401.2 W
Max Power & Breaker14.38 kW20A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 20A at 250m
| Cross-Section (mm²) | Cu Ampacity | Al Ampacity | Cu Voltage Drop | Load Voltage | Al Voltage Drop | Power Loss | Status |
|---|---|---|---|---|---|---|---|
| 1.5 mm² | 16 A | 12 A | 123.55 V (29.77%) | 291.4 V | 203.8 V (49.11%) | 4280.0 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 74.13 V (17.86%) | 340.9 V | 122.28 V (29.47%) | 2568.0 W | Drop High |
| 4 mm² | 32 A | 25 A | 46.33 V (11.16%) | 368.7 V | 76.43 V (18.42%) | 1605.0 W | Drop High |
| 6 mm² | 41 A | 32 A | 30.89 V (7.44%) | 384.1 V | 50.95 V (12.28%) | 1070.0 W | Drop High |
| 10 mm² | 57 A | 44 A | 18.53 V (4.47%) | 396.5 V | 30.57 V (7.37%) | 642.0 W | ~ ≤5% |
| 16 mm² | 76 A | 59 A | 11.58 V (2.79%) | 403.4 V | 19.11 V (4.6%) | 401.2 W | ✓ OK (≤3%) |
| 25 mm² | 101 A | 78 A | 7.41 V (1.79%) | 407.6 V | 12.23 V (2.95%) | 256.8 W | ✓ OK (≤3%) |
| 35 mm² | 125 A | 97 A | 5.3 V (1.28%) | 409.7 V | 8.73 V (2.1%) | 183.4 W | ✓ OK (≤3%) |
| 50 mm² | 151 A | 118 A | 3.71 V (0.89%) | 411.3 V | 6.11 V (1.47%) | 128.4 W | ✓ OK (≤3%) |
| 70 mm² | 192 A | 150 A | 2.65 V (0.64%) | 412.4 V | 4.37 V (1.05%) | 91.7 W | ✓ OK (≤3%) |
| 95 mm² | 232 A | 181 A | 1.95 V (0.47%) | 413.0 V | 3.22 V (0.78%) | 67.6 W | ✓ OK (≤3%) |
| 120 mm² | 269 A | 210 A | 1.54 V (0.37%) | 413.5 V | 2.55 V (0.61%) | 53.5 W | ✓ OK (≤3%) |
| 150 mm² | 309 A | 241 A | 1.24 V (0.3%) | 413.8 V | 2.04 V (0.49%) | 42.8 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 1.0 V (0.24%) | 414.0 V | 1.65 V (0.4%) | 34.7 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 0.77 V (0.19%) | 414.2 V | 1.27 V (0.31%) | 26.7 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 0.62 V (0.15%) | 414.4 V | 1.02 V (0.25%) | 21.4 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 0.46 V (0.11%) | 414.5 V | 0.76 V (0.18%) | 16.1 W | ✓ OK (≤3%) |
FAQ — 20 Amp Cable Size at 250 Meters (415V Three-Phase (UK / Australia Industrial))
What mm² cable size is required for 20A at 250 meters (415V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 16 mm² copper cable for 20A over 250m at 415V (voltage drop: 11.58V or 2.79%).
What is the power capacity of 20A at 415V?
At unity power factor, 20A at 415V supports 14.38 kW with a standard 20A circuit breaker.
Related Lengths & Currents (415V)
20A · 5m (415V)20A · 10m (415V)20A · 15m (415V)20A · 20m (415V)20A · 25m (415V)20A · 30m (415V)20A · 35m (415V)20A · 40m (415V)20A · 45m (415V)20A · 50m (415V)20A · 60m (415V)20A · 70m (415V)10A · 250m (415V)16A · 250m (415V)25A · 250m (415V)32A · 250m (415V)40A · 250m (415V)50A · 250m (415V)63A · 250m (415V)80A · 250m (415V)100A · 250m (415V)125A · 250m (415V)160A · 250m (415V)200A · 250m (415V)