Wire Size for 345.55 Amps

Typical copper and aluminum wire gauges for 345.55 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.

345.55A Wire Gauge by Distance

Distance	Copper Gauge	Aluminum Gauge	V-Drop (Cu)	NEC Status
25 ft	500 kcmil	750 kcmil	0.4458V (0.3715%)	check_circle OK
50 ft	500 kcmil	750 kcmil	0.8915V (0.7429%)	check_circle OK
75 ft	500 kcmil	750 kcmil	1.34V (1.11%)	check_circle OK
100 ft	500 kcmil	750 kcmil	1.78V (1.49%)	check_circle OK
125 ft	500 kcmil	750 kcmil	2.23V (1.86%)	check_circle OK
150 ft	500 kcmil	750 kcmil	2.67V (2.23%)	check_circle OK
175 ft	500 kcmil	750 kcmil	3.12V (2.6%)	check_circle OK
200 ft	500 kcmil	no aluminum pick	3.57V (2.97%)	check_circle OK
250 ft	750 kcmil	no aluminum pick	2.95V (2.46%)	check_circle OK
300 ft	750 kcmil	no aluminum pick	3.55V (2.95%)	check_circle OK
400 ft	Exceeds available gauges
500 ft	Exceeds available gauges

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.

Also Calculate

electric_bolt 345.55A to watts at 120V trending_down Voltage drop calculator

Other Amperages

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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.