20 Amp Cable Size at 120 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 120 m (393.7 ft).
Copper Cable (≤3% Drop)10 mm²Drop: 8.9V (2.14%)
Aluminum Cable (≤3% Drop)16 mm²Drop: 9.17V (2.21%)
Voltage at Load406.1 VLine Loss: 308.2 W
Max Power & Breaker14.38 kW20A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 20A at 120m
| 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 | 59.31 V (14.29%) | 355.7 V | 97.83 V (23.57%) | 2054.4 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 35.58 V (8.57%) | 379.4 V | 58.7 V (14.14%) | 1232.6 W | Drop High |
| 4 mm² | 32 A | 25 A | 22.24 V (5.36%) | 392.8 V | 36.68 V (8.84%) | 770.4 W | Drop High |
| 6 mm² | 41 A | 32 A | 14.83 V (3.57%) | 400.2 V | 24.46 V (5.89%) | 513.6 W | ~ ≤5% |
| 10 mm² | 57 A | 44 A | 8.9 V (2.14%) | 406.1 V | 14.67 V (3.54%) | 308.2 W | ✓ OK (≤3%) |
| 16 mm² | 76 A | 59 A | 5.56 V (1.34%) | 409.4 V | 9.17 V (2.21%) | 192.6 W | ✓ OK (≤3%) |
| 25 mm² | 101 A | 78 A | 3.56 V (0.86%) | 411.4 V | 5.87 V (1.41%) | 123.3 W | ✓ OK (≤3%) |
| 35 mm² | 125 A | 97 A | 2.54 V (0.61%) | 412.5 V | 4.19 V (1.01%) | 88.0 W | ✓ OK (≤3%) |
| 50 mm² | 151 A | 118 A | 1.78 V (0.43%) | 413.2 V | 2.93 V (0.71%) | 61.6 W | ✓ OK (≤3%) |
| 70 mm² | 192 A | 150 A | 1.27 V (0.31%) | 413.7 V | 2.1 V (0.51%) | 44.0 W | ✓ OK (≤3%) |
| 95 mm² | 232 A | 181 A | 0.94 V (0.23%) | 414.1 V | 1.54 V (0.37%) | 32.4 W | ✓ OK (≤3%) |
| 120 mm² | 269 A | 210 A | 0.74 V (0.18%) | 414.3 V | 1.22 V (0.29%) | 25.7 W | ✓ OK (≤3%) |
| 150 mm² | 309 A | 241 A | 0.59 V (0.14%) | 414.4 V | 0.98 V (0.24%) | 20.5 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 0.48 V (0.12%) | 414.5 V | 0.79 V (0.19%) | 16.7 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 0.37 V (0.09%) | 414.6 V | 0.61 V (0.15%) | 12.8 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 0.3 V (0.07%) | 414.7 V | 0.49 V (0.12%) | 10.3 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 0.22 V (0.05%) | 414.8 V | 0.37 V (0.09%) | 7.7 W | ✓ OK (≤3%) |
FAQ — 20 Amp Cable Size at 120 Meters (415V Three-Phase (UK / Australia Industrial))
What mm² cable size is required for 20A at 120 meters (415V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 10 mm² copper cable for 20A over 120m at 415V (voltage drop: 8.9V or 2.14%).
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 · 120m (415V)16A · 120m (415V)25A · 120m (415V)32A · 120m (415V)40A · 120m (415V)50A · 120m (415V)63A · 120m (415V)80A · 120m (415V)100A · 120m (415V)125A · 120m (415V)160A · 120m (415V)200A · 120m (415V)