What Is the Voltage Drop for 2 AWG at 114A and 25 Feet?
Running 114A through 2 AWG copper for 25 feet on a single-phase / DC circuit produces a 1.11-volt drop. On a 120V source that is 0.9215%; on 240V it is 0.4607%. NEC 210.19(A) Informational Note 4 recommends keeping branch-circuit drop at or below 3% and total feeder+branch drop at or below 5%, these are performance recommendations, not code requirements.
Use this citation when referencing this page.
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 →
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)
Vdrop = (2 × L × I × R) ÷ 1000
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 = (Vdrop ÷ Vsource) × 100
How This Estimate Changes with Run Length and Gauge
Gauge Check
2 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 2 AWG at 114A at different distances:
| Distance | Drop (V) | % on 120V | % on 240V | NEC (120V) |
|---|---|---|---|---|
| 25ft | 1.11V | 0.9215% | 0.4607% | OK |
| 50ft | 2.21V | 1.84% | 0.9215% | OK |
| 75ft | 3.32V | 2.76% | 1.38% | OK |
| 100ft | 4.42V | 3.69% | 1.84% | Caution |
| 150ft | 6.63V | 5.53% | 2.76% | Past 5% |
| 200ft | 8.85V | 7.37% | 3.69% | Past 5% |
| 300ft | 13.27V | 11.06% | 5.53% | Past 5% |
Same Run, Different Wire Gauges
How does wire gauge affect voltage drop for 114A at 25 feet on 120V single-phase / DC? Only gauges whose branch-circuit OCP cap is at or above the 114A load are listed, since thinner gauges would fail the ampacity check before drop even matters.