⚡ 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 40 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 40 m (131.2 ft).

Copper Cable (≤3% Drop)35 mm²Drop: 5.3V (1.32%)
Aluminum Cable (≤3% Drop)70 mm²Drop: 4.37V (1.09%)
Voltage at Load394.7 VLine Loss: 1146.4 W
Max Power & Breaker86.6 kW125A MCB/MCCB

IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 125A at 40m

Cross-Section (mm²)Cu AmpacityAl Ampacity Cu Voltage DropLoad VoltageAl Voltage DropPower LossStatus
1.5 mm²16 A12 A123.55 V (30.89%)276.4 V203.8 V (50.95%)26750.0 WDrop High
2.5 mm²24 A18 A74.13 V (18.53%)325.9 V122.28 V (30.57%)16050.0 WDrop High
4 mm²32 A25 A46.33 V (11.58%)353.7 V76.43 V (19.11%)10031.2 WDrop High
6 mm²41 A32 A30.89 V (7.72%)369.1 V50.95 V (12.74%)6687.5 WDrop High
10 mm²57 A44 A18.53 V (4.63%)381.5 V30.57 V (7.64%)4012.5 WDrop High
16 mm²76 A59 A11.58 V (2.9%)388.4 V19.11 V (4.78%)2507.8 WDrop High
25 mm²101 A78 A7.41 V (1.85%)392.6 V12.23 V (3.06%)1605.0 WDrop High
35 mm²125 A97 A5.3 V (1.32%)394.7 V8.73 V (2.18%)1146.4 W✓ OK (≤3%)
50 mm²151 A118 A3.71 V (0.93%)396.3 V6.11 V (1.53%)802.5 W✓ OK (≤3%)
70 mm²192 A150 A2.65 V (0.66%)397.4 V4.37 V (1.09%)573.2 W✓ OK (≤3%)
95 mm²232 A181 A1.95 V (0.49%)398.0 V3.22 V (0.8%)422.4 W✓ OK (≤3%)
120 mm²269 A210 A1.54 V (0.39%)398.5 V2.55 V (0.64%)334.4 W✓ OK (≤3%)
150 mm²309 A241 A1.24 V (0.31%)398.8 V2.04 V (0.51%)267.5 W✓ OK (≤3%)
185 mm²353 A275 A1.0 V (0.25%)399.0 V1.65 V (0.41%)216.9 W✓ OK (≤3%)
240 mm²415 A324 A0.77 V (0.19%)399.2 V1.27 V (0.32%)167.2 W✓ OK (≤3%)
300 mm²477 A372 A0.62 V (0.15%)399.4 V1.02 V (0.25%)133.8 W✓ OK (≤3%)
400 mm²570 A445 A0.46 V (0.12%)399.5 V0.76 V (0.19%)100.3 W✓ OK (≤3%)

FAQ — 125 Amp Cable Size at 40 Meters (400V Three-Phase (IEC European Grid))

What mm² cable size is required for 125A at 40 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 40m at 400V (voltage drop: 5.3V or 1.32%).

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.