Wire Sizing

What Size Wire for 200 Amp 300 Feet Away

Pre-calculated NEC-compliant wire size for 200 amps at 300 feet on a 240V single-phase circuit. Immediate answer below.

Recommended Wire Size

Copper

250 kcmil

Voltage drop: 2.57% (6.18V)

Voltage at load: 233.8V

Controlling factor: Voltage Drop (3% limit)

Aluminum

400 kcmil

Voltage drop: 2.65% (6.35V)

Voltage at load: 233.7V

Controlling factor: Voltage Drop (3% limit)

Based on NEC Table 310.16 (75°C column), single-phase, 240V, 3% max voltage drop, one-way distance 300 ft.

Wire Comparison Table

Wire Size	Ampacity	V-Drop (V)	V-Drop (%)	V at Load
14 AWG	15A	376.8V	157%	-136.8V
12 AWG	20A	237.6V	99%	2.4V
10 AWG	30A	148.8V	62%	91.2V
8 AWG	50A	93.36V	38.9%	146.6V
6 AWG	65A	58.92V	24.55%	181.1V
4 AWG	85A	36.96V	15.4%	203V
3 AWG	100A	29.4V	12.25%	210.6V
2 AWG	115A	23.28V	9.7%	216.7V
1 AWG	130A	18.48V	7.7%	221.5V
1/0 AWG	150A	14.64V	6.1%	225.4V
2/0 AWG	175A	11.6V	4.83%	228.4V
3/0 AWG	200A	9.19V	3.83%	230.8V
4/0 AWG	230A	7.3V	3.04%	232.7V
250 kcmilREC	255A	6.18V	2.57%	233.8V
300 kcmil	285A	5.15V	2.15%	234.9V
350 kcmil	310A	4.4V	1.83%	235.6V
400 kcmil	335A	3.85V	1.6%	236.1V
500 kcmil	380A	3.1V	1.29%	236.9V

Table shows all standard AWG/kcmil sizes for 200A at 300 ft on 240V (copper). Green check = meets both ampacity and 3% voltage drop. REC = smallest compliant size.

Key Considerations

A 200 amp service at 300 feet typically requires large conductors where voltage drop becomes the controlling factor rather than ampacity. Consider parallel runs of smaller conductors if the required size exceeds what fits in available conduit.

For aluminum conductors at this amperage, ensure all terminations use AL-CU rated lugs and apply anti-oxidant compound. Aluminum is significantly cheaper for large feeders and is standard practice for service entrance conductors.

For runs exceeding 200 feet, conduit fill becomes important. Verify that the selected wire size fits within the maximum fill allowance of your conduit per NEC Chapter 9, Table 1. Consider upsizing the conduit rather than downsizing the conductor.

Frequently Asked Questions

What size wire do I need for a 200 amp service at 300 feet?▾

For a 200A/240V circuit at 300 feet, use 250 kcmil copper (2.57% drop) or 400 kcmil aluminum. This keeps voltage drop within the NEC-recommended 3% limit.

Can I use aluminum wire for a 200 amp circuit?▾

Yes. Aluminum wire is a cost-effective alternative for larger circuits. For 200A at 300 feet, use 400 kcmil aluminum (2.65% voltage drop). Aluminum requires AL-rated connectors and anti-oxidant compound at all terminations.

What happens if the voltage drop exceeds 3%?▾

Voltage drop above 3% reduces equipment efficiency, can cause motors to overheat, and may violate NEC 210.19(A) Informational Note No. 4. For a 200A circuit at 300 feet on 240V, exceeding 3% means the load receives less than 232.8V, which can damage sensitive electronics and shorten appliance lifespan.

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Need a Custom Calculation?

Different voltage, three-phase, or custom max drop percentage? Use our interactive calculator.

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