Welder Amps, Watts & Breaker Size

Welder Power Requirements at a Glance#

A welder runs on 240 volts and draws its rated current only in short arcs. A stick welder pulls 40 to 48 amps for 9,600 to 11,520 watts on a 50-amp circuit through a 6-50R or 14-50R outlet, while a lighter wire-feed machine draws 20 to 24 amps and 4,800 to 5,760 watts on a 30-amp circuit through a 6-30R outlet.

Welder Electrical Specifications#

A welder draws its rated current only in short arcs rather than continuously, so the code lets the circuit be sized to the duty cycle rather than the full nameplate, which is why a shop welder can share a 50-amp receptacle with other intermittent tools. The heavier stick machine claims the larger plug, while a light wire-feed unit is happy on a smaller branch.

Circuit and Breaker Sizing for the Welder#

Because a welder strikes an arc for seconds and then rests, the code lets the circuit be sized to its duty cycle rather than the full nameplate current, so a stick machine at 40 to 48 amps rides 8 or 6-gauge copper on a 50-amp breaker without treating it as a continuous load. A wire-feed unit at 20 to 24 amps drops to 10-gauge on a 30-amp breaker. That intermittent draw is also why a shop welder can share a 50-amp receptacle with other tools that are never running at the same instant.

Dedicated Circuit and Disconnect for the Welder#

A welder is usually given a branch of its own with a nearby receptacle or disconnect, though its arc-only duty is gentle enough that a well-planned shop may feed a couple of intermittent 240-volt tools from one circuit. Sizing follows the machine's stamped rating and duty cycle rather than the peak amps mid-arc, since that momentary draw is not sustained. The keyed 240-volt receptacle itself acts as the disconnect — unplugging the machine isolates it before any service.

Installation and Safety Notes for Welder Wiring#

Match the welder's cord cap to the receptacle it needs: a 6-50R or 14-50R for a stick machine, a 6-30R for a wire-feed unit, and never force one into the wrong outlet. A new 240-volt, 50-amp branch is permit-and-inspection work, with the inspector checking the conductor against the breaker. Plugging a welder into an existing 240-volt receptacle is straightforward, but running a new 50-amp circuit for the shop should go to a licensed electrician.

Welder Electrical FAQ#

What breaker does a 240-volt welder need?#

A stick welder sits on a 50-amp breaker and a wire-feed machine on a 30-amp one. Duty-cycle sizing keeps those from being padded further.

Why can a welder be sized to its duty cycle?#

Because it draws its rated current only in short arcs with rests between, the code allows the circuit to be sized to that intermittent duty rather than a continuous full-load draw.

Which receptacle does a stick welder plug into?#

A stick welder uses a keyed 240-volt outlet, a 6-50R or 14-50R, matched to its 50-amp circuit. The keying prevents a wrong connection.

Can a small wire-feed welder run on a 30-amp circuit?#

Yes. A light wire-feed machine draws 20 to 24 amps and runs on a 30-amp branch through a 6-30R outlet.

How much current does a welder pull mid-arc?#

A stick welder draws 40 to 48 amps while the arc is struck, and a wire-feed unit 20 to 24. Between arcs the draw drops sharply.

Does a garage welder need a dedicated circuit?#

Usually it gets one, but its arc-only duty is gentle enough that a shop may run a couple of intermittent 240-volt tools from a single well-planned circuit.