40 Amp Cable Size at 20 Meters (690V Three-Phase (Wind / Heavy Industrial))
IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 40 A over 20 m (65.6 ft).
Copper Cable (≤3% Drop)6 mm²Drop: 4.94V (0.72%)
Aluminum Cable (≤3% Drop)10 mm²Drop: 4.89V (0.71%)
Voltage at Load685.1 VLine Loss: 342.4 W
Max Power & Breaker47.8 kW40A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 40A at 20m
| 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 | 19.77 V (2.86%) | 670.2 V | 32.61 V (4.73%) | 1369.6 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 11.86 V (1.72%) | 678.1 V | 19.57 V (2.84%) | 821.8 W | Drop High |
| 4 mm² | 32 A | 25 A | 7.41 V (1.07%) | 682.6 V | 12.23 V (1.77%) | 513.6 W | Drop High |
| 6 mm² | 41 A | 32 A | 4.94 V (0.72%) | 685.1 V | 8.15 V (1.18%) | 342.4 W | ✓ OK (≤3%) |
| 10 mm² | 57 A | 44 A | 2.97 V (0.43%) | 687.0 V | 4.89 V (0.71%) | 205.4 W | ✓ OK (≤3%) |
| 16 mm² | 76 A | 59 A | 1.85 V (0.27%) | 688.1 V | 3.06 V (0.44%) | 128.4 W | ✓ OK (≤3%) |
| 25 mm² | 101 A | 78 A | 1.19 V (0.17%) | 688.8 V | 1.96 V (0.28%) | 82.2 W | ✓ OK (≤3%) |
| 35 mm² | 125 A | 97 A | 0.85 V (0.12%) | 689.2 V | 1.4 V (0.2%) | 58.7 W | ✓ OK (≤3%) |
| 50 mm² | 151 A | 118 A | 0.59 V (0.09%) | 689.4 V | 0.98 V (0.14%) | 41.1 W | ✓ OK (≤3%) |
| 70 mm² | 192 A | 150 A | 0.42 V (0.06%) | 689.6 V | 0.7 V (0.1%) | 29.3 W | ✓ OK (≤3%) |
| 95 mm² | 232 A | 181 A | 0.31 V (0.05%) | 689.7 V | 0.51 V (0.07%) | 21.6 W | ✓ OK (≤3%) |
| 120 mm² | 269 A | 210 A | 0.25 V (0.04%) | 689.8 V | 0.41 V (0.06%) | 17.1 W | ✓ OK (≤3%) |
| 150 mm² | 309 A | 241 A | 0.2 V (0.03%) | 689.8 V | 0.33 V (0.05%) | 13.7 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 0.16 V (0.02%) | 689.8 V | 0.26 V (0.04%) | 11.1 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 0.12 V (0.02%) | 689.9 V | 0.2 V (0.03%) | 8.6 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 0.1 V (0.01%) | 689.9 V | 0.16 V (0.02%) | 6.8 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 0.07 V (0.01%) | 689.9 V | 0.12 V (0.02%) | 5.1 W | ✓ OK (≤3%) |
FAQ — 40 Amp Cable Size at 20 Meters (690V Three-Phase (Wind / Heavy Industrial))
What mm² cable size is required for 40A at 20 meters (690V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 6 mm² copper cable for 40A over 20m at 690V (voltage drop: 4.94V or 0.72%).
What is the power capacity of 40A at 690V?
At unity power factor, 40A at 690V supports 47.8 kW with a standard 40A circuit breaker.
Related Lengths & Currents (690V)
40A · 5m (690V)40A · 10m (690V)40A · 15m (690V)40A · 25m (690V)40A · 30m (690V)40A · 35m (690V)40A · 40m (690V)40A · 45m (690V)40A · 50m (690V)40A · 60m (690V)40A · 70m (690V)10A · 20m (690V)16A · 20m (690V)20A · 20m (690V)25A · 20m (690V)32A · 20m (690V)50A · 20m (690V)63A · 20m (690V)80A · 20m (690V)100A · 20m (690V)125A · 20m (690V)160A · 20m (690V)200A · 20m (690V)