20 Amp Cable Size at 40 Meters (690V Three-Phase (Wind / Heavy Industrial))
IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 20 A over 40 m (131.2 ft).
Copper Cable (≤3% Drop)2.5 mm²Drop: 11.86V (1.72%)
Aluminum Cable (≤3% Drop)4 mm²Drop: 12.23V (1.77%)
Voltage at Load678.1 VLine Loss: 410.9 W
Max Power & Breaker23.9 kW20A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 20A at 40m
| 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%) | 684.8 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 11.86 V (1.72%) | 678.1 V | 19.57 V (2.84%) | 410.9 W | ✓ OK (≤3%) |
| 4 mm² | 32 A | 25 A | 7.41 V (1.07%) | 682.6 V | 12.23 V (1.77%) | 256.8 W | ✓ OK (≤3%) |
| 6 mm² | 41 A | 32 A | 4.94 V (0.72%) | 685.1 V | 8.15 V (1.18%) | 171.2 W | ✓ OK (≤3%) |
| 10 mm² | 57 A | 44 A | 2.97 V (0.43%) | 687.0 V | 4.89 V (0.71%) | 102.7 W | ✓ OK (≤3%) |
| 16 mm² | 76 A | 59 A | 1.85 V (0.27%) | 688.1 V | 3.06 V (0.44%) | 64.2 W | ✓ OK (≤3%) |
| 25 mm² | 101 A | 78 A | 1.19 V (0.17%) | 688.8 V | 1.96 V (0.28%) | 41.1 W | ✓ OK (≤3%) |
| 35 mm² | 125 A | 97 A | 0.85 V (0.12%) | 689.2 V | 1.4 V (0.2%) | 29.3 W | ✓ OK (≤3%) |
| 50 mm² | 151 A | 118 A | 0.59 V (0.09%) | 689.4 V | 0.98 V (0.14%) | 20.5 W | ✓ OK (≤3%) |
| 70 mm² | 192 A | 150 A | 0.42 V (0.06%) | 689.6 V | 0.7 V (0.1%) | 14.7 W | ✓ OK (≤3%) |
| 95 mm² | 232 A | 181 A | 0.31 V (0.05%) | 689.7 V | 0.51 V (0.07%) | 10.8 W | ✓ OK (≤3%) |
| 120 mm² | 269 A | 210 A | 0.25 V (0.04%) | 689.8 V | 0.41 V (0.06%) | 8.6 W | ✓ OK (≤3%) |
| 150 mm² | 309 A | 241 A | 0.2 V (0.03%) | 689.8 V | 0.33 V (0.05%) | 6.8 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 0.16 V (0.02%) | 689.8 V | 0.26 V (0.04%) | 5.6 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 0.12 V (0.02%) | 689.9 V | 0.2 V (0.03%) | 4.3 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 0.1 V (0.01%) | 689.9 V | 0.16 V (0.02%) | 3.4 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 0.07 V (0.01%) | 689.9 V | 0.12 V (0.02%) | 2.6 W | ✓ OK (≤3%) |
FAQ — 20 Amp Cable Size at 40 Meters (690V Three-Phase (Wind / Heavy Industrial))
What mm² cable size is required for 20A at 40 meters (690V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 2.5 mm² copper cable for 20A over 40m at 690V (voltage drop: 11.86V or 1.72%).
What is the power capacity of 20A at 690V?
At unity power factor, 20A at 690V supports 23.9 kW with a standard 20A circuit breaker.
Related Lengths & Currents (690V)
20A · 5m (690V)20A · 10m (690V)20A · 15m (690V)20A · 20m (690V)20A · 25m (690V)20A · 30m (690V)20A · 35m (690V)20A · 45m (690V)20A · 50m (690V)20A · 60m (690V)20A · 70m (690V)10A · 40m (690V)16A · 40m (690V)25A · 40m (690V)32A · 40m (690V)40A · 40m (690V)50A · 40m (690V)63A · 40m (690V)80A · 40m (690V)100A · 40m (690V)125A · 40m (690V)160A · 40m (690V)200A · 40m (690V)