Voltage drop by wire size (60 A, 150 ft, 240 V)
| Copper wire | Drop (V) | Drop (%) | Within 3% |
|---|---|---|---|
| 6 AWG | 8.84 V | 3.68% | ✗ |
| 4 AWG | 5.54 V | 2.31% | ✓ |
| 3 AWG | 4.41 V | 1.84% | ✓ |
| 2 AWG | 3.49 V | 1.46% | ✓ |
| 1 AWG | 2.77 V | 1.16% | ✓ |
Voltage drop = 2 × 150 ft × 60 A × resistance ÷ 1000. Keeping it under 3% on branch circuits (5% total) is the NEC recommendation in the informational notes to 210.19 and 215.2.
Frequently asked questions
Is 6 AWG enough for 60 amps at 150 feet?
It carries 60 A, but at 150 ft the voltage drop is 3.7%. That is over 3%, so the next size up is recommended.
Does the distance include the return wire?
No. Enter the one-way distance; the formula already counts both conductors.