Wire Size for 178.75 Amps

Typical copper and aluminum wire gauges for 178.75 amps across common run lengths on a 120V circuit, sized to keep voltage drop under 3% and respect the NEC 240.4(D) small-conductor rule. Actual install sizing depends on conductor material, insulation/termination temperature rating, cable type, ambient and bundling derates, and local code.

178.75A Wire Gauge by Distance

DistanceCopper GaugeAluminum GaugeV-Drop (Cu)NEC Status
25 ft 3/0 AWG 4/0 AWG 0.6846V (0.5705%) check_circle OK
50 ft 3/0 AWG 4/0 AWG 1.37V (1.14%) check_circle OK
75 ft 3/0 AWG 4/0 AWG 2.05V (1.71%) check_circle OK
100 ft 3/0 AWG 4/0 AWG 2.74V (2.28%) check_circle OK
125 ft 3/0 AWG 300 kcmil 3.42V (2.85%) check_circle OK
150 ft 4/0 AWG 350 kcmil 3.26V (2.72%) check_circle OK
175 ft 250 kcmil 500 kcmil 3.22V (2.68%) check_circle OK
200 ft 300 kcmil 500 kcmil 3.07V (2.56%) check_circle OK
250 ft 350 kcmil 750 kcmil 3.28V (2.73%) check_circle OK
300 ft 500 kcmil 750 kcmil 2.77V (2.31%) check_circle OK
400 ft 750 kcmil no aluminum pick 2.45V (2.04%) check_circle OK
500 ft 750 kcmil no aluminum pick 3.06V (2.55%) check_circle OK

Aluminum is not typical for 10 AWG and smaller branch-circuit conductors in residential settings. Copper gauges use the NEC 240.4(D) branch-circuit cap, not raw 75°C ampacity.

Other Amperages

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.