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What Size Wire for a 80 Amp Breaker?

A 80 A breaker needs 4 AWG copper or 2 AWG aluminum with 75°C terminations (NEC Table 310.16). Longer runs may need a size up for voltage drop: distances below.

Minimum wire size for 80 amps

ApplicationCopper (75°C)Aluminum (75°C)
Branch circuit / feeder (Table 310.16)4 AWG2 AWG

Assumes 75°C-rated terminations (NEC 110.14(C)). Both assume no more than three current-carrying conductors in a raceway at 30°C ambient. Derating, continuous loads, and local amendments can change the answer: confirm with a licensed electrician.

Ground wire for 80 amps

GroundCopperAluminum
Equipment ground (bare / green) (Table 250.122)8 AWG6 AWG

The equipment ground is sized by the breaker, not the load: a 80A breaker falls in Table 250.122's 100 A row. Upsize the hots for voltage drop and the ground must grow in proportion (NEC 250.122(B)). Every size, with a worked upsizing example, is in the ground wire size chart.

How far can you run it? (voltage drop)

Keeping voltage drop under the recommended 3% at a 64 A load (80% of the breaker), 4 AWG copper is good for roughly:

System voltageMax one-way run (4 AWG Cu)
240 V≈ 182 ft

Past these distances, step up one gauge. Run your exact length and load through the voltage drop calculator.

What runs on 80 amps

  • Subpanel feeder
  • 64 A EV charging (hardwired)

Parts for a 80 A circuit

Before touching a 80 A circuit, confirm it is dead with a voltage pen; a clamp meter reads the real load on one of its conductors.

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Frequently asked questions

4 AWG copper with 75°C terminations (NEC Table 310.16). In aluminum, use 2 AWG. Longer runs, high ambient temperatures, or bundling can require upsizing.

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