What Is the Voltage Drop for 14 AWG at 2A and 250 Feet?
14 AWG copper carrying 2 amps over 250 feet on a single-phase / DC circuit drops 3.14 volts (2.62% on a 120V source). This sits within the 3% branch target and the 5% feeder+branch total target that NEC 210.19(A) Informational Note 4 cites. Both are planning targets, 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
14 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 14 AWG at 2A at different distances:
| Distance | Drop (V) | % on 120V | % on 240V | NEC (120V) |
|---|---|---|---|---|
| 25ft | 0.314V | 0.2617% | 0.1308% | OK |
| 50ft | 0.628V | 0.5233% | 0.2617% | OK |
| 75ft | 0.942V | 0.785% | 0.3925% | OK |
| 100ft | 1.26V | 1.05% | 0.5233% | OK |
| 150ft | 1.88V | 1.57% | 0.785% | OK |
| 200ft | 2.51V | 2.09% | 1.05% | OK |
| 300ft | 3.77V | 3.14% | 1.57% | Caution |
Same Run, Different Wire Gauges
How does wire gauge affect voltage drop for 2A at 250 feet on 120V single-phase / DC? Only gauges whose branch-circuit OCP cap is at or above the 2A load are listed, since thinner gauges would fail the ampacity check before drop even matters.