What Gauge Extension Cord for a Welder?
For a typical 120V wire-feed or stick welder drawing roughly 20A, our Appliance Amp Draw → Gauge table calls for a minimum of 12 AWG at 25-50ft, stepping up to 8 AWG at 100ft and 6 AWG at 150ft. Always check your specific welder's nameplate input current first — "20A" is a typical figure, not a universal one.
Input current, not output/weld current
Cord sizing is based on the welder's INPUT amperage draw from the wall, not the weld amperage it outputs to the arc. Check the nameplate on the machine itself for the actual input current rating at your voltage.
Duty cycle and heat
Welding involves sustained, continuous current draw for the duration of each pass, which builds heat in an undersized cord faster than an intermittent load would. It's another reason to size up rather than run at the bare calculated minimum for equipment used in long, hot sessions.
240V welders are a different circuit entirely
Larger 240V welders draw high current on a dedicated circuit — this is permanent-wiring territory, not a portable extension cord decision. Consult a licensed electrician for correct circuit sizing and code compliance.
This page is general reference, not an electrical code determination.
Frequently Asked Questions
For a typical 120V wire-feed or stick welder drawing about 20A, our Appliance Amp Draw to Gauge table calls for a minimum of 12 AWG at 25-50ft, stepping up to 8 AWG at 100ft and 6 AWG at 150ft. Larger 240V welders draw far more current and typically require a dedicated circuit sized by a licensed electrician, not a portable extension cord.
Only if it's rated at or above your welder's actual input amperage at your specific run length — most standard 16 AWG household cords are undersized for any welder. Check your welder's nameplate input current (not output/weld current) first.
Duty cycle affects how long the welder draws current continuously, which affects HEAT buildup in an undersized cord over a welding session — it's another reason to size up rather than run at the bare minimum gauge for a tool used in long, hot, continuous pulls.
240V welders (many MIG/TIG/stick machines used for thicker material) draw high current on a dedicated circuit, not a portable extension cord in most cases. That's permanent-wiring territory — consult a licensed electrician for correct circuit sizing and code compliance.