1/0 AWG voltage drop at 75 feet
Computed voltage drop for 1/0 AWG copper conductors on a 75 ft one-way run.
2.20 V
drop on 1/0 AWG copper, 75 ft one-way, 120 A load · 1.8% of 120 V · 0.9% of 240 V
1/0 AWG at 75 ft by load
| Load | Drop | % at 120 V | % at 240 V | 3% rule (240 V) |
|---|---|---|---|---|
| 30 A | 0.55 V | 0.5% | 0.2% | OK |
| 60 A | 1.10 V | 0.9% | 0.5% | OK |
| 90 A | 1.65 V | 1.4% | 0.7% | OK |
| 120 A | 2.20 V | 1.8% | 0.9% | OK |
Vd = 2 × length × R × I ÷ 1000, R = 0.122 Ω/1000 ft (copper, NEC Ch. 9 Table 8). Aluminum is about 1.6× higher.
Same wire, other distances
25 ft · 50 ft · 100 ft · 125 ft · 150 ft · 200 ft · 250 ft · 300 ft
FAQ
What is the voltage drop on 1/0 AWG wire at 75 feet?
At 120 A (80% of its 150 A 75°C rating) 1/0 AWG copper drops 2.20 V over 75 ft one-way: 1.8% at 120 V or 0.9% at 240 V.
How far can I run 1/0 AWG at 120 amps?
To stay within 3% at 120 V, about 123 ft one-way; at 240 V about 246 ft.