Wire Sizing

What Size Wire for 150 Amp 150 Feet Away

Pre-calculated NEC-compliant wire size for 150 amps at 150 feet on a 240V single-phase circuit. Immediate answer below.

Recommended Wire Size

Copper

1/0 AWG

Voltage drop: 2.29% (5.49V)

Voltage at load: 234.5V

Controlling factor: Ampacity (NEC 310.16)

Aluminum

3/0 AWG

Voltage drop: 2.36% (5.67V)

Voltage at load: 234.3V

Controlling factor: Ampacity (NEC 310.16)

Based on NEC Table 310.16 (75°C column), single-phase, 240V, 3% max voltage drop, one-way distance 150 ft.

Wire Comparison Table

Wire Size	Ampacity	V-Drop (V)	V-Drop (%)	V at Load
14 AWG	15A	141.3V	58.88%	98.7V
12 AWG	20A	89.1V	37.12%	150.9V
10 AWG	30A	55.8V	23.25%	184.2V
8 AWG	50A	35.01V	14.59%	205V
6 AWG	65A	22.1V	9.21%	217.9V
4 AWG	85A	13.86V	5.78%	226.1V
3 AWG	100A	11.03V	4.59%	229V
2 AWG	115A	8.73V	3.64%	231.3V
1 AWG	130A	6.93V	2.89%	233.1V
1/0 AWGREC	150A	5.49V	2.29%	234.5V
2/0 AWG	175A	4.35V	1.81%	235.6V
3/0 AWG	200A	3.45V	1.44%	236.6V
4/0 AWG	230A	2.74V	1.14%	237.3V
250 kcmil	255A	2.32V	0.97%	237.7V
300 kcmil	285A	1.93V	0.8%	238.1V
350 kcmil	310A	1.65V	0.69%	238.3V
400 kcmil	335A	1.44V	0.6%	238.6V
500 kcmil	380A	1.16V	0.48%	238.8V

Table shows all standard AWG/kcmil sizes for 150A at 150 ft on 240V (copper). Green check = meets both ampacity and 3% voltage drop. REC = smallest compliant size.

Key Considerations

For a 150A circuit at 150 feet on 240V, both ampacity and voltage drop must be satisfied. NEC recommends keeping the total voltage drop (feeder + branch) under 5%, with no more than 3% on either segment alone.

Copper conductors at 75°C column (THHN/THWN-2) are assumed. If using 60°C terminations, derate the ampacity to the 60°C column values. Verify the temperature rating of your terminals.

Frequently Asked Questions

What size wire do I need for a 150 amp service at 150 feet?▾

For a 150A/240V circuit at 150 feet, use 1/0 AWG copper (2.29% drop) or 3/0 AWG aluminum. This keeps voltage drop within the NEC-recommended 3% limit.

Can I use aluminum wire for a 150 amp circuit?▾

Yes. Aluminum wire is a cost-effective alternative for larger circuits. For 150A at 150 feet, use 3/0 AWG aluminum (2.36% 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 150A circuit at 150 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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