Wire Sizing

What Size Wire for 150 Amp 100 Feet Away

Pre-calculated NEC-compliant wire size for 150 amps at 100 feet on a 240V single-phase circuit. Immediate answer below.

Recommended Wire Size

Copper

1/0 AWG

Voltage drop: 1.53% (3.66V)

Voltage at load: 236.3V

Controlling factor: Ampacity (NEC 310.16)

Aluminum

3/0 AWG

Voltage drop: 1.57% (3.78V)

Voltage at load: 236.2V

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 100 ft.

Wire Comparison Table

Wire Size	Ampacity	V-Drop (V)	V-Drop (%)	V at Load
14 AWG	15A	94.2V	39.25%	145.8V
12 AWG	20A	59.4V	24.75%	180.6V
10 AWG	30A	37.2V	15.5%	202.8V
8 AWG	50A	23.34V	9.73%	216.7V
6 AWG	65A	14.73V	6.14%	225.3V
4 AWG	85A	9.24V	3.85%	230.8V
3 AWG	100A	7.35V	3.06%	232.7V
2 AWG	115A	5.82V	2.43%	234.2V
1 AWG	130A	4.62V	1.93%	235.4V
1/0 AWGREC	150A	3.66V	1.53%	236.3V
2/0 AWG	175A	2.9V	1.21%	237.1V
3/0 AWG	200A	2.3V	0.96%	237.7V
4/0 AWG	230A	1.82V	0.76%	238.2V
250 kcmil	255A	1.55V	0.64%	238.5V
300 kcmil	285A	1.29V	0.54%	238.7V
350 kcmil	310A	1.1V	0.46%	238.9V
400 kcmil	335A	0.96V	0.4%	239V
500 kcmil	380A	0.77V	0.32%	239.2V

Table shows all standard AWG/kcmil sizes for 150A at 100 ft on 240V (copper). Green check = meets both ampacity and 3% voltage drop. REC = smallest compliant size.

Key Considerations

For a 150A circuit at 100 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 100 feet?▾

For a 150A/240V circuit at 100 feet, use 1/0 AWG copper (1.53% 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 100 feet, use 3/0 AWG aluminum (1.57% 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 100 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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