⚡ Cu ρ (75°C): 0.0214 Ω·mm²/m 🔌 NEC / IEC Standards: NFPA 70 & IEC 60364 🇺🇸 US Grid Avg: $0.175/kWh 🇩🇪 DE Grid Avg: €0.345/kWh 🇸🇪 SE Elpris: 1.54 SEK/kWh 🇳🇴 NO Strøm: 1.17 NOK/kWh 🔩 Copper Ref: $9,650/t (2026-10-24)
⚡ IEC 60364-5-52 · DIN VDE · NEK 400 · SS 436 40 00

125 Amp Cable Size at 15 Meters (400V Three-Phase (IEC European Grid))

IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 125 A over 15 m (49.2 ft).

Copper Cable (≤3% Drop)35 mm²Drop: 1.99V (0.5%)
Aluminum Cable (≤3% Drop)70 mm²Drop: 1.64V (0.41%)
Voltage at Load398.0 VLine Loss: 429.9 W
Max Power & Breaker86.6 kW125A MCB/MCCB

IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 125A at 15m

Cross-Section (mm²)Cu AmpacityAl Ampacity Cu Voltage DropLoad VoltageAl Voltage DropPower LossStatus
1.5 mm²16 A12 A46.33 V (11.58%)353.7 V76.43 V (19.11%)10031.2 WDrop High
2.5 mm²24 A18 A27.8 V (6.95%)372.2 V45.86 V (11.46%)6018.8 WDrop High
4 mm²32 A25 A17.37 V (4.34%)382.6 V28.66 V (7.17%)3761.7 WDrop High
6 mm²41 A32 A11.58 V (2.9%)388.4 V19.11 V (4.78%)2507.8 WDrop High
10 mm²57 A44 A6.95 V (1.74%)393.1 V11.46 V (2.87%)1504.7 WDrop High
16 mm²76 A59 A4.34 V (1.09%)395.7 V7.17 V (1.79%)940.4 WDrop High
25 mm²101 A78 A2.78 V (0.69%)397.2 V4.59 V (1.15%)601.9 WDrop High
35 mm²125 A97 A1.99 V (0.5%)398.0 V3.28 V (0.82%)429.9 W✓ OK (≤3%)
50 mm²151 A118 A1.39 V (0.35%)398.6 V2.29 V (0.57%)300.9 W✓ OK (≤3%)
70 mm²192 A150 A0.99 V (0.25%)399.0 V1.64 V (0.41%)215.0 W✓ OK (≤3%)
95 mm²232 A181 A0.73 V (0.18%)399.3 V1.21 V (0.3%)158.4 W✓ OK (≤3%)
120 mm²269 A210 A0.58 V (0.14%)399.4 V0.96 V (0.24%)125.4 W✓ OK (≤3%)
150 mm²309 A241 A0.46 V (0.12%)399.5 V0.76 V (0.19%)100.3 W✓ OK (≤3%)
185 mm²353 A275 A0.38 V (0.09%)399.6 V0.62 V (0.15%)81.3 W✓ OK (≤3%)
240 mm²415 A324 A0.29 V (0.07%)399.7 V0.48 V (0.12%)62.7 W✓ OK (≤3%)
300 mm²477 A372 A0.23 V (0.06%)399.8 V0.38 V (0.1%)50.2 W✓ OK (≤3%)
400 mm²570 A445 A0.17 V (0.04%)399.8 V0.29 V (0.07%)37.6 W✓ OK (≤3%)

FAQ — 125 Amp Cable Size at 15 Meters (400V Three-Phase (IEC European Grid))

What mm² cable size is required for 125A at 15 meters (400V)?

According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 35 mm² copper cable for 125A over 15m at 400V (voltage drop: 1.99V or 0.5%).

What is the power capacity of 125A at 400V?

At unity power factor, 125A at 400V supports 86.6 kW with a standard 125A circuit breaker.