2/0 AWG voltage drop at 250 feet
Computed voltage drop for 2/0 AWG copper conductors on a 250 ft one-way run.
6.77 V
drop on 2/0 AWG copper, 250 ft one-way, 140 A load · 5.6% of 120 V · 2.8% of 240 V
2/0 AWG at 250 ft by load
| Load | Drop | % at 120 V | % at 240 V | 3% rule (240 V) |
|---|---|---|---|---|
| 35 A | 1.69 V | 1.4% | 0.7% | OK |
| 70 A | 3.38 V | 2.8% | 1.4% | OK |
| 105 A | 5.08 V | 4.2% | 2.1% | OK |
| 140 A | 6.77 V | 5.6% | 2.8% | OK |
Vd = 2 × length × R × I ÷ 1000, R = 0.0967 Ω/1000 ft (copper, NEC Ch. 9 Table 8). Aluminum is about 1.6× higher.
Same wire, other distances
25 ft · 50 ft · 75 ft · 100 ft · 125 ft · 150 ft · 200 ft · 300 ft
FAQ
What is the voltage drop on 2/0 AWG wire at 250 feet?
At 140 A (80% of its 175 A 75°C rating) 2/0 AWG copper drops 6.77 V over 250 ft one-way: 5.6% at 120 V or 2.8% at 240 V.
How far can I run 2/0 AWG at 140 amps?
To stay within 3% at 120 V, about 133 ft one-way; at 240 V about 266 ft.