What Size Breaker for Welder?
A welder requires a 50A breaker with 6 AWG wire on a 240V dedicated circuit.
🔌 Wire Length & Voltage Drop Check
Welder Wiring Guide — NEC Requirements
Welders have high intermittent current draws. A typical 240V welder needs a 40-50A circuit. NEC 630.12 allows sizing based on duty cycle — a 200A welder at 20% duty cycle needs conductors rated for 100A.
Pro Tip
💡 Check the welder duty cycle rating. Size the breaker for the actual input current, not the welding output current.
Why a 50A Breaker?
The welder draws approximately 40A at 240V (9600W). A 50A breaker provides adequate protection.
Wire Sizing per NEC 310.16
For a 50A/240V circuit, 6 AWG copper is required per NEC Table 310.16 at 75°C. For runs over 75 feet, upsize to 4 AWG. Use our Wire Size Calculator and Voltage Drop Calculator.
Complete Parts List
To wire a welder circuit: a 50A double-pole breaker, 6 AWG NM-B cable (Romex) for interior runs or THHN/THWN-2 in conduit for exposed runs, a NEMA 14-50 receptacle (or hardwired), cable clamps, and appropriate junction boxes.
Disclaimer: This guide is for reference only. All electrical work must be performed by or verified by a licensed electrician. Local codes may differ from NEC.