What Wire Size for 150 Amps?

Copper Wire

1/0 AWG

8.2515 mm · 53.4751 mm²

Aluminum Wire

3/0 AWG

10.4049 mm · 85.0288 mm²

Breaker: 150A · Based on NEC Table 310.16, 75°C column (NEC 110.14(C) above 100A)

150-Amp Wire Size by Termination Rating

Rule	Copper	Aluminum
75°C column — NEC Table 310.16	1/0 AWG	3/0 AWG
Dwelling service or main feeder — NEC 310.12 (83% = 124.5A)	1 AWG	2/0 AWG

Above 100A, NEC 110.14(C)(1)(b) allows the 75°C column when terminations are rated 75°C, which is standard for this equipment.

Common Uses for 150A Circuits

Service entrance, commercial panels

1/0 AWG Copper — Key Specs

Diameter	8.2515 mm (0.324861")
Area	53.4751 mm²
Resistance at 20°C	0.3224 Ω/km
Weight	479.137 kg/km
Ampacity (75°C)	150 A

Important: For long wire runs, you may need to upsize the wire to compensate for voltage drop. NEC recommends keeping voltage drop under 3% for branch circuits. Use our voltage drop calculator to check.

Voltage Drop by Distance — 1/0 AWG Copper at 150A

One-way run	Drop	% of 240V	Verdict
25 ft	0.92 V	0.4%	Within the 3% branch-circuit target
50 ft	1.83 V	0.8%	Within the 3% branch-circuit target
75 ft	2.75 V	1.1%	Within the 3% branch-circuit target
100 ft	3.66 V	1.5%	Within the 3% branch-circuit target
150 ft	5.49 V	2.3%	Within the 3% branch-circuit target
200 ft	7.32 V	3.1%	Over 3% — upsize one gauge

Single-phase, 240V, full 150A load, 0.122 Ω/1000 ft DC resistance (NEC Chapter 9, Table 8) at 75°C terminations. NEC 210.19(A) Informational Note recommends keeping branch-circuit drop at or below 3%, and 5% total across feeder plus branch circuit. Voltage drop is a performance recommendation, not a code requirement — but exceeding it causes dim lights, slow motor starts, and wasted energy.

Aluminum Feeder Specifications

Aluminum has about 61% of copper’s conductivity, so a 150A feeder that takes 2/0 AWG copper needs 3/0 AWG aluminum — typically one to two gauge sizes larger.

Aluminum conductor	3/0 AWG
Ampacity (75°C, Table 310.16)	155 A
Copper equivalent	1/0 AWG (150 A)
Resistance	0.095 Ω/1000 ft
Voltage drop at 100 ft, 150A	3.78 V (1.6% of 240V)

Installing aluminum correctly

Modern aluminum building wire must be AA-8000 series alloy (NEC 310.14(A)(1)). The 1960s-era AA-1350 alloy behind aluminum’s bad reputation is no longer permitted for branch circuits.
Terminate only on lugs and breakers marked AL/CU or AL9CU. Copper-only terminals are the most common failure point.
Apply an antioxidant compound to the stripped conductor before landing it, unless the termination is listed as not requiring it.
Torque every connection to the manufacturer’s value with a calibrated torque tool — NEC 110.14(D) makes this mandatory. Loose aluminum terminations are the primary cause of feeder failures.
Aluminum runs roughly half the weight and a third to half the cost of copper at feeder sizes, which is why it dominates service entrance and sub-panel feeders.

Frequently Asked Questions

What wire size do I need for 150 amps?

For a 150-amp circuit, NEC Table 310.16 at 75°C calls for 1/0 AWG copper (150A) or 3/0 AWG aluminum (155A). If it is the service or main feeder for a dwelling, NEC 310.12 allows sizing at 83% (124.5A): 1 AWG copper or 2/0 AWG aluminum.

What breaker do I need for 150 amps?

A 150-amp circuit uses a 150A double-pole circuit breaker. The breaker protects the 1/0 AWG copper (or 3/0 AWG aluminum) wire from overload. Double-pole breakers are used for 240V circuits and occupy two slots in the panel.

What size wire for a 150-amp service entrance?

A 150-amp dwelling service can be sized under NEC 310.12 at 83% (124.5A): 1 AWG copper or 2/0 aluminum. Other 150A feeders use Table 310.16 at 75°C: 1/0 copper or 3/0 aluminum. Aluminum SER or SEU cable is the usual choice at this size and must be listed for service-entrance use.

Is 150A service enough for a modern home?

A 150-amp service is sufficient for most homes with gas heating and cooking. It becomes limiting if you add electric vehicle charging (requiring 48A continuous), electric heat, or electric cooking. Many electricians now recommend upgrading to 200A to future-proof the home.

Wire size for other amperages

15A 20A 30A 40A 50A 60A 70A 80A 100A 125A 200A

Circuit breaker size chart → Wire types and insulation ratings → NEC Table 250.122 — ground wire size → 1/0 AWG full specifications → Full AWG chart → Wire size calculator → Ampacity tables →