What Is the Voltage Drop for 4/0 AWG at 112A and 250 Feet?

4/0 AWG at 112A and 250 feet: 3.4V drop (2.84% on 120V), computed on the single-phase / DC basis. Every conductor has resistance, and longer runs at higher currents drop more voltage. Use this calculation to check whether your run clears the 3% branch-circuit drop target before pulling wire.

4/0 AWG, 112A, 250ft · single-phase / DC

3.4 V drop (2.84% on 120V)

On 120V circuit2.84%

On 240V circuit1.42%

Circuit basis: This uses the single-phase / DC round-trip formula (factor of 2) for the voltage drop across the two circuit conductors. For a three-phase line-to-line run use the three-phase version of the page (append ?type=3ph). Switch to the three-phase version →

Gauge

4/0 AWG

Amps

Feet

Drop @ 120V

3.40V (2.84%)

Assumes a 120V source on a single-phase / DC circuit. Use the circuit-basis link above to switch between single-phase/DC and three-phase.

Voltage Drop Formula (single-phase / DC)

V_drop = (2 × L × I × R) ÷ 1000

(2 × 250 × 112 × 0.0608) ÷ 1000 = 3.4 V

DC and single-phase AC use the round-trip factor of 2. Current travels out to the load on one conductor and returns on another.

For a three-phase circuit at the same amps and distance, see the three-phase version (uses √3 instead of 2, so the drop is about 13.4% lower).

Percentage

%VD = (V_drop ÷ V_source) × 100

On 120V: (3.4 ÷ 120) × 100 = 2.84%

On 240V: (3.4 ÷ 240) × 100 = 1.42%

How This Estimate Changes with Run Length and Gauge

Gauge Check

4/0 AWG clears the 3% drop target at these inputs. A smaller conductor may also meet it with less margin. See the minimum gauge for this load and distance.

Impact of Distance

Voltage drop is proportional to distance. Here is 4/0 AWG at 112A at different distances:

Distance	Drop (V)	% on 120V	% on 240V	NEC (120V)
25ft	0.3405V	0.2837%	0.1419%	OK
50ft	0.681V	0.5675%	0.2837%	OK
75ft	1.02V	0.8512%	0.4256%	OK
100ft	1.36V	1.13%	0.5675%	OK
150ft	2.04V	1.7%	0.8512%	OK
200ft	2.72V	2.27%	1.13%	OK
300ft	4.09V	3.4%	1.7%	Caution

Same Run, Different Wire Gauges

How does wire gauge affect voltage drop for 112A at 250 feet on 120V single-phase / DC? Only gauges whose branch-circuit OCP cap is at or above the 112A load are listed, since thinner gauges would fail the ampacity check before drop even matters.

Gauge	Drop (V)	% on 120V	% on 240V	3% Target (120V)
4/0 AWG	3.4V	2.84%	1.42%	OK
250 kcmil	2.88V	2.4%	1.2%	OK
300 kcmil	2.4V	2%	1%	OK
350 kcmil	2.06V	1.71%	0.8563%	OK
500 kcmil	1.44V	1.2%	0.602%	OK
750 kcmil	0.9576V	0.798%	0.399%	OK

Related Calculations

cable Wire size: 112A, 250ft bolt Watts to amps calculator functions Voltage drop formula

Frequently Asked Questions

What is the voltage drop for 4/0 AWG at 112A and 250ft?expand_more

4/0 AWG carrying 112A over 250ft has a 3.4V drop (2.84% on 120V). Reference: 1.42% on 240V.

What wire gauge should I use instead of 4/0 AWG for this run?expand_more

4/0 AWG already sits within the 3% branch-circuit drop target at these inputs (2.84% on 120V). Going to a larger gauge is only useful if you want more headroom for future load growth, longer runs, or tighter drop targets like the 5% feeder+branch total recommendation used in sensitive or motor-heavy installations.

Does 4/0 AWG meet the 3% drop target at 112A and 250ft on 120V?expand_more

On 120V, this run sits at 2.84%, which is within the 3% branch and 5% feeder+branch total drop targets. NEC 210.19(A) Informational Note 4 cites 3% for branch circuits and 5% for total feeder+branch drop as performance recommendations, not hard code requirements.

Is voltage drop worse on 120V or 240V?expand_more

Same wire, same amps, same distance: the volts dropped are identical. But the percentage is worse on 120V because the drop is a larger fraction of the source voltage. This run would be 1.42% on 240V versus 2.84% on 120V.

Why does distance affect voltage drop?expand_more

Voltage drop is proportional to distance. The formula multiplies by 2 × the distance (out and back). Doubling the run doubles the drop.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.