Skip to content

What Size Wire for a 50 Amp Breaker?

A 50 A breaker needs 8 AWG copper or 6 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 50 amps

ApplicationCopper (75°C)Aluminum (75°C)
Branch circuit / feeder (Table 310.16)8 AWG6 AWG
Worth knowing: 8 AWG copper is the 75°C code minimum at exactly 50 A. Many installers run 6 AWG anyway — it costs little more and covers voltage drop and 60°C terminations.

Assumes 75°C-rated terminations (NEC 110.14(C)) and 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.

How far can you run it? (voltage drop)

Keeping voltage drop under the recommended 3% at a 40 A load (80% of the breaker), 8 AWG copper is good for roughly:

System voltageMax one-way run (8 AWG Cu)
120 V≈ 57 ft
240 V≈ 115 ft

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

What runs on 50 amps

  • Range/cooktop
  • 40 A EV charger
  • RV receptacle (14-50)
  • Welder circuit

Common receptacles at this rating: NEMA 14-50, NEMA 6-50.

Frequently asked questions

8 AWG copper with 75°C terminations (NEC Table 310.16). In aluminum, use 6 AWG. Longer runs, high ambient temperatures, or bundling can require upsizing.

Ask AI about this

Open an AI assistant with a question grounded in this page.

ChatGPTClaudePerplexityGoogle AIGrok
Full wire & breaker chartVoltage drop calculatorEV charger breaker sizing

Other amperages