What Is the Voltage Drop for 4/0 AWG at 194A and 150 Feet?

4/0 AWG at 194A and 150 feet: 3.54V drop (2.95% 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, 194A, 150ft · single-phase / DC
3.54 V drop (2.95% on 120V)
On 120V circuit2.95%
On 240V circuit1.47%

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 →

4/0 AWG
3.54V (2.95%)

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

(2 × 150 × 194 × 0.0608) ÷ 1000 = 3.54 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 = (Vdrop ÷ Vsource) × 100

On 120V: (3.54 ÷ 120) × 100 = 2.95%
On 240V: (3.54 ÷ 240) × 100 = 1.47%

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 194A at different distances:

DistanceDrop (V)% on 120V% on 240VNEC (120V)
25ft0.5898V0.4915%0.2457%OK
50ft1.18V0.9829%0.4915%OK
75ft1.77V1.47%0.7372%OK
100ft2.36V1.97%0.9829%OK
150ft3.54V2.95%1.47%OK
200ft4.72V3.93%1.97%Caution
300ft7.08V5.9%2.95%Past 5%

Same Run, Different Wire Gauges

How does wire gauge affect voltage drop for 194A at 150 feet on 120V single-phase / DC? Only gauges whose branch-circuit OCP cap is at or above the 194A load are listed, since thinner gauges would fail the ampacity check before drop even matters.

GaugeDrop (V)% on 120V% on 240V3% Target (120V)
4/0 AWG3.54V2.95%1.47%OK
250 kcmil3V2.5%1.25%OK
300 kcmil2.5V2.08%1.04%OK
350 kcmil2.14V1.78%0.89%OK
500 kcmil1.5V1.25%0.6257%OK
750 kcmil0.9952V0.8294%0.4147%OK

Frequently Asked Questions

4/0 AWG carrying 194A over 150ft has a 3.54V drop (2.95% on 120V). Reference: 1.47% on 240V.
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 1.47% on 240V versus 2.95% on 120V.
Motors run hotter and can have trouble starting under load. Incandescent and halogen lighting dims. Some electronics misbehave at the low end of their input tolerance. Energy is wasted as I²R heating in the conductor. These are performance issues; high drop is not itself a code violation unless the specific installation cites a hard limit.
On 120V, this run sits at 2.95%, 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.
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.