125 Amp Cable Size at 250 Meters (690V Three-Phase (Wind / Heavy Industrial))
IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 125 A over 250 m (820.2 ft).
Copper Cable (≤3% Drop)70 mm²Drop: 16.55V (2.4%)
Aluminum Cable (≤3% Drop)95 mm²Drop: 20.11V (2.91%)
Voltage at Load673.5 VLine Loss: 3582.6 W
Max Power & Breaker149.39 kW125A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 125A 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 | 772.21 V (111.91%) | 0.0 V | 1273.78 V (184.61%) | 167187.5 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 463.32 V (67.15%) | 226.7 V | 764.27 V (110.76%) | 100312.5 W | Drop High |
| 4 mm² | 32 A | 25 A | 289.58 V (41.97%) | 400.4 V | 477.67 V (69.23%) | 62695.3 W | Drop High |
| 6 mm² | 41 A | 32 A | 193.05 V (27.98%) | 496.9 V | 318.44 V (46.15%) | 41796.9 W | Drop High |
| 10 mm² | 57 A | 44 A | 115.83 V (16.79%) | 574.2 V | 191.07 V (27.69%) | 25078.1 W | Drop High |
| 16 mm² | 76 A | 59 A | 72.39 V (10.49%) | 617.6 V | 119.42 V (17.31%) | 15673.8 W | Drop High |
| 25 mm² | 101 A | 78 A | 46.33 V (6.71%) | 643.7 V | 76.43 V (11.08%) | 10031.2 W | Drop High |
| 35 mm² | 125 A | 97 A | 33.09 V (4.8%) | 656.9 V | 54.59 V (7.91%) | 7165.2 W | ~ ≤5% |
| 50 mm² | 151 A | 118 A | 23.17 V (3.36%) | 666.8 V | 38.21 V (5.54%) | 5015.6 W | ~ ≤5% |
| 70 mm² | 192 A | 150 A | 16.55 V (2.4%) | 673.5 V | 27.3 V (3.96%) | 3582.6 W | ✓ OK (≤3%) |
| 95 mm² | 232 A | 181 A | 12.19 V (1.77%) | 677.8 V | 20.11 V (2.91%) | 2639.8 W | ✓ OK (≤3%) |
| 120 mm² | 269 A | 210 A | 9.65 V (1.4%) | 680.3 V | 15.92 V (2.31%) | 2089.8 W | ✓ OK (≤3%) |
| 150 mm² | 309 A | 241 A | 7.72 V (1.12%) | 682.3 V | 12.74 V (1.85%) | 1671.9 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 6.26 V (0.91%) | 683.7 V | 10.33 V (1.5%) | 1355.6 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 4.83 V (0.7%) | 685.2 V | 7.96 V (1.15%) | 1044.9 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 3.86 V (0.56%) | 686.1 V | 6.37 V (0.92%) | 835.9 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 2.9 V (0.42%) | 687.1 V | 4.78 V (0.69%) | 627.0 W | ✓ OK (≤3%) |
FAQ — 125 Amp Cable Size at 250 Meters (690V Three-Phase (Wind / Heavy Industrial))
What mm² cable size is required for 125A at 250 meters (690V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 70 mm² copper cable for 125A over 250m at 690V (voltage drop: 16.55V or 2.4%).
What is the power capacity of 125A at 690V?
At unity power factor, 125A at 690V supports 149.39 kW with a standard 125A circuit breaker.
Related Lengths & Currents (690V)
125A · 5m (690V)125A · 10m (690V)125A · 15m (690V)125A · 20m (690V)125A · 25m (690V)125A · 30m (690V)125A · 35m (690V)125A · 40m (690V)125A · 45m (690V)125A · 50m (690V)125A · 60m (690V)125A · 70m (690V)10A · 250m (690V)16A · 250m (690V)20A · 250m (690V)25A · 250m (690V)32A · 250m (690V)40A · 250m (690V)50A · 250m (690V)63A · 250m (690V)80A · 250m (690V)100A · 250m (690V)160A · 250m (690V)200A · 250m (690V)