20 Amp Cable Size at 120 Meters (24V DC (Off-Grid Solar / Industrial Control))
IEC 60364-5-52 metric conductor sizing (mm²), voltage drop, and power loss calculation for 20 A over 120 m (393.7 ft).
Copper Cable (≤3% Drop)150 mm²Drop: 0.68V (2.85%)
Aluminum Cable (≤3% Drop)240 mm²Drop: 0.71V (2.94%)
Voltage at Load23.3 VLine Loss: 13.7 W
Max Power & Breaker0.48 kW20A MCB/MCCB
IEC 60364 Cable Cross-Section Table (1.5 mm² – 400 mm²) for 20A at 120m
| 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 | 68.48 V (285.33%) | 0.0 V | 112.96 V (470.67%) | 1369.6 W | Drop High |
| 2.5 mm² | 24 A | 18 A | 41.09 V (171.2%) | 0.0 V | 67.78 V (282.4%) | 821.8 W | Drop High |
| 4 mm² | 32 A | 25 A | 25.68 V (107.0%) | 0.0 V | 42.36 V (176.5%) | 513.6 W | Drop High |
| 6 mm² | 41 A | 32 A | 17.12 V (71.33%) | 6.9 V | 28.24 V (117.67%) | 342.4 W | Drop High |
| 10 mm² | 57 A | 44 A | 10.27 V (42.8%) | 13.7 V | 16.94 V (70.6%) | 205.4 W | Drop High |
| 16 mm² | 76 A | 59 A | 6.42 V (26.75%) | 17.6 V | 10.59 V (44.12%) | 128.4 W | Drop High |
| 25 mm² | 101 A | 78 A | 4.11 V (17.12%) | 19.9 V | 6.78 V (28.24%) | 82.2 W | Drop High |
| 35 mm² | 125 A | 97 A | 2.93 V (12.23%) | 21.1 V | 4.84 V (20.17%) | 58.7 W | Drop High |
| 50 mm² | 151 A | 118 A | 2.05 V (8.56%) | 21.9 V | 3.39 V (14.12%) | 41.1 W | Drop High |
| 70 mm² | 192 A | 150 A | 1.47 V (6.11%) | 22.5 V | 2.42 V (10.09%) | 29.3 W | Drop High |
| 95 mm² | 232 A | 181 A | 1.08 V (4.51%) | 22.9 V | 1.78 V (7.43%) | 21.6 W | ~ ≤5% |
| 120 mm² | 269 A | 210 A | 0.86 V (3.57%) | 23.1 V | 1.41 V (5.88%) | 17.1 W | ~ ≤5% |
| 150 mm² | 309 A | 241 A | 0.68 V (2.85%) | 23.3 V | 1.13 V (4.71%) | 13.7 W | ✓ OK (≤3%) |
| 185 mm² | 353 A | 275 A | 0.56 V (2.31%) | 23.4 V | 0.92 V (3.82%) | 11.1 W | ✓ OK (≤3%) |
| 240 mm² | 415 A | 324 A | 0.43 V (1.78%) | 23.6 V | 0.71 V (2.94%) | 8.6 W | ✓ OK (≤3%) |
| 300 mm² | 477 A | 372 A | 0.34 V (1.43%) | 23.7 V | 0.56 V (2.35%) | 6.8 W | ✓ OK (≤3%) |
| 400 mm² | 570 A | 445 A | 0.26 V (1.07%) | 23.7 V | 0.42 V (1.76%) | 5.1 W | ✓ OK (≤3%) |
FAQ — 20 Amp Cable Size at 120 Meters (24V DC (Off-Grid Solar / Industrial Control))
What mm² cable size is required for 20A at 120 meters (24V)?
According to IEC 60364-5-52 ampacity and the 3% maximum voltage drop standard, you need 150 mm² copper cable for 20A over 120m at 24V (voltage drop: 0.68V or 2.85%).
What is the power capacity of 20A at 24V?
At unity power factor, 20A at 24V supports 0.48 kW with a standard 20A circuit breaker.
Related Lengths & Currents (24V)
20A · 5m (24V)20A · 10m (24V)20A · 15m (24V)20A · 20m (24V)20A · 25m (24V)20A · 30m (24V)20A · 35m (24V)20A · 40m (24V)20A · 45m (24V)20A · 50m (24V)20A · 60m (24V)20A · 70m (24V)10A · 120m (24V)16A · 120m (24V)25A · 120m (24V)32A · 120m (24V)40A · 120m (24V)50A · 120m (24V)63A · 120m (24V)80A · 120m (24V)100A · 120m (24V)125A · 120m (24V)160A · 120m (24V)200A · 120m (24V)