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🇺🇸 NEC NFPA 70 · Table 310.16 (75°C) · Voltage Drop Analysis

225 Amp Wire Size at 500 Feet (240V Split-Phase (US Dryer / EV / Subpanel))

Complete conductor sizing, Ohm's law voltage drop, $I^2R$ line power loss, and circuit breaker specification for a 225 A load over a 500 ft (152.4 m) one-way run.

Copper Wire (≤3% Drop)500 kcmil253.4 mm² · Drop: 2.41%
Aluminum Wire (≤3% Drop)750 kcmilDrop: 6.37V (2.65%)
Voltage at Load End234.2 VLoss: 5.79 V (1303.1 W)
Power & Breaker (125%)54.0 kW300A Breaker Recommended

All AWG & kcmil Wire Gauges for 225 Amps at 500 Feet (240V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A705.58 V (293.99%)0.0 V1163.88 V (484.95%)158756.1 WDrop/Amp High
12 AWG3.31 mm²20 A443.39 V (184.74%)0.0 V731.38 V (304.74%)99762.1 WDrop/Amp High
10 AWG5.26 mm²30 A279.01 V (116.26%)0.0 V460.24 V (191.77%)62778.1 WDrop/Amp High
8 AWG8.37 mm²50 A175.34 V (73.06%)64.7 V289.23 V (120.51%)39451.9 WDrop/Amp High
6 AWG13.3 mm²65 A110.35 V (45.98%)129.7 V182.02 V (75.84%)24828.0 WDrop/Amp High
4 AWG21.15 mm²85 A69.39 V (28.91%)170.6 V114.46 V (47.69%)15612.9 WDrop/Amp High
3 AWG26.67 mm²100 A55.03 V (22.93%)185.0 V90.77 V (37.82%)12381.4 WDrop/Amp High
2 AWG33.62 mm²115 A43.65 V (18.19%)196.3 V72.01 V (30.0%)9821.9 WDrop/Amp High
1 AWG42.41 mm²130 A34.61 V (14.42%)205.4 V57.08 V (23.78%)7786.2 WDrop/Amp High
1/0 AWG53.49 mm²150 A27.44 V (11.43%)212.6 V45.26 V (18.86%)6173.4 WDrop/Amp High
2/0 AWG67.43 mm²175 A21.76 V (9.07%)218.2 V35.9 V (14.96%)4897.1 WDrop/Amp High
3/0 AWG85.01 mm²200 A17.26 V (7.19%)222.7 V28.48 V (11.87%)3884.4 WDrop/Amp High
4/0 AWG107.2 mm²230 A13.69 V (5.7%)226.3 V22.58 V (9.41%)3080.3 WDrop/Amp High
250 kcmil126.7 mm²255 A11.58 V (4.83%)228.4 V19.11 V (7.96%)2606.3 W~ ≤5%
300 kcmil152.0 mm²285 A9.66 V (4.02%)230.3 V15.93 V (6.64%)2172.5 W~ ≤5%
350 kcmil177.3 mm²310 A8.28 V (3.45%)231.7 V13.65 V (5.69%)1862.5 W~ ≤5%
400 kcmil202.7 mm²335 A7.24 V (3.02%)232.8 V11.94 V (4.98%)1629.1 W~ ≤5%
500 kcmil253.4 mm²380 A5.79 V (2.41%)234.2 V9.55 V (3.98%)1303.1 W✓ PASS (≤3%)
600 kcmil304.0 mm²420 A4.83 V (2.01%)235.2 V7.96 V (3.32%)1086.2 W✓ PASS (≤3%)
750 kcmil380.0 mm²475 A3.86 V (1.61%)236.1 V6.37 V (2.65%)869.0 W✓ PASS (≤3%)
1000 kcmil506.7 mm²545 A2.9 V (1.21%)237.1 V4.78 V (1.99%)651.7 W✓ PASS (≤3%)

Frequently Asked Engineering Questions

What size copper wire do I need for 225 amps at 500 feet (240V)?

To stay within the NEC recommended 3% maximum voltage drop for a 225A load over 500 feet one-way at 240V (1-Phase), you need 500 kcmil copper wire. This produces a voltage drop of 5.79V (2.41%) and delivers 234.2V at the load.

What size aluminum wire is required for 225 amps at 500 feet?

Using aluminum conductors (75°C rating), you should use 750 kcmil to maintain voltage drop at 6.37V (2.65%).

What breaker size is needed for a 225A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (225A × 1.25 = 281.2A), which corresponds to a standard 300A circuit breaker.