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

650 Amp Wire Size at 1000 Feet (240V Three-Phase (US Industrial Delta))

Complete conductor sizing, Ohm's law voltage drop, $I^2R$ line power loss, and circuit breaker specification for a 650 A load over a 1000 ft (304.8 m) one-way run.

Copper Wire (≤3% Drop)3× 1000 kcmil (Parallel)506.7 mm² · Drop: 2.01%
Aluminum Wire (≤3% Drop)1000 kcmilDrop: 23.91V (9.96%)
Voltage at Load End235.2 VLoss: 4.83 V (5438.8 W)
Power & Breaker (125%)270.2 kW1000A Breaker Recommended

All AWG & kcmil Wire Gauges for 650 Amps at 1000 Feet (240V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A3530.53 V (1471.05%)0.0 V5823.72 V (2426.55%)3974782.5 WDrop/Amp High
12 AWG3.31 mm²20 A2218.58 V (924.41%)0.0 V3659.62 V (1524.84%)2497748.5 WDrop/Amp High
10 AWG5.26 mm²30 A1396.1 V (581.71%)0.0 V2302.91 V (959.55%)1571777.1 WDrop/Amp High
8 AWG8.37 mm²50 A877.36 V (365.57%)0.0 V1447.23 V (603.01%)987759.6 WDrop/Amp High
6 AWG13.3 mm²65 A552.14 V (230.06%)0.0 V910.78 V (379.49%)621620.1 WDrop/Amp High
4 AWG21.15 mm²85 A347.21 V (144.67%)0.0 V572.73 V (238.64%)390900.6 WDrop/Amp High
3 AWG26.67 mm²100 A275.35 V (114.73%)0.0 V454.19 V (189.25%)309994.3 WDrop/Amp High
2 AWG33.62 mm²115 A218.43 V (91.01%)21.6 V360.3 V (150.13%)245911.6 WDrop/Amp High
1 AWG42.41 mm²130 A173.15 V (72.15%)66.8 V285.62 V (119.01%)194943.4 WDrop/Amp High
1/0 AWG53.49 mm²150 A137.29 V (57.2%)102.7 V226.46 V (94.36%)154562.5 WDrop/Amp High
2/0 AWG67.43 mm²175 A108.91 V (45.38%)131.1 V179.64 V (74.85%)122609.3 WDrop/Amp High
3/0 AWG85.01 mm²200 A86.38 V (35.99%)153.6 V142.49 V (59.37%)97253.8 WDrop/Amp High
4/0 AWG107.2 mm²230 A68.5 V (28.54%)171.5 V113.0 V (47.08%)77122.6 WDrop/Amp High
250 kcmil126.7 mm²255 A57.96 V (24.15%)182.0 V95.61 V (39.84%)65252.9 WDrop/Amp High
300 kcmil152.0 mm²285 A48.31 V (20.13%)191.7 V79.69 V (33.21%)54391.8 WDrop/Amp High
350 kcmil177.3 mm²310 A41.42 V (17.26%)198.6 V68.32 V (28.47%)46630.3 WDrop/Amp High
400 kcmil202.7 mm²335 A36.23 V (15.1%)203.8 V59.76 V (24.9%)40787.1 WDrop/Amp High
500 kcmil253.4 mm²380 A28.98 V (12.07%)211.0 V47.8 V (19.92%)32626.5 WDrop/Amp High
600 kcmil304.0 mm²420 A24.16 V (10.07%)215.8 V39.85 V (16.6%)27195.9 WDrop/Amp High
750 kcmil380.0 mm²475 A19.32 V (8.05%)220.7 V31.88 V (13.28%)21756.7 WDrop/Amp High
1000 kcmil506.7 mm²545 A14.49 V (6.04%)225.5 V23.91 V (9.96%)16316.5 WDrop/Amp High

Frequently Asked Engineering Questions

What size copper wire do I need for 650 amps at 1000 feet (240V)?

To stay within the NEC recommended 3% maximum voltage drop for a 650A load over 1000 feet one-way at 240V (3-Phase), you need 3× 1000 kcmil (Parallel) copper wire. This produces a voltage drop of 4.83V (2.01%) and delivers 235.2V at the load.

What size aluminum wire is required for 650 amps at 1000 feet?

Using aluminum conductors (75°C rating), you should use 1000 kcmil to maintain voltage drop at 23.91V (9.96%).

What breaker size is needed for a 650A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (650A × 1.25 = 812.5A), which corresponds to a standard 1000A circuit breaker.