ElectraKit
Industrial equipment circuits

Welding Circuit Sizing Calculator

Screen individual welder circuit conductor and overcurrent-device values using nameplate current and user-entered rule factors.

Welder supply circuit

Enter nameplate and rule inputs

A
×
×
A
A

Entered sizing check

Both selected values meet the entered checks
Calculated minimum conductor ampacity70 A
Selected conductor checkPass
Calculated maximum protection rating112 A
Selected protection checkPass
Screening worksheet onlyEnter factors from the applicable adopted NEC rules for the exact welder type and installation. This does not select a conductor or device, apply all correction factors, verify group installations, or establish code compliance.

About this calculator

Compare a welder circuit conductor’s adjusted ampacity and selected overcurrent-device rating with limits calculated from nameplate current and factors entered by the user.

The inputs are deliberately explicit because applicable sizing rules vary by welder type, operating duty, and installation.

Method and assumptions

Calculated conductor minimum = nameplate current × duty-cycle factor × conductor factor. Calculated maximum protection = nameplate current × duty-cycle factor × protection factor.

This limited arithmetic does not include all NEC conditions, group installations, conductor adjustment/correction, equipment instructions, or other loads.

FAQs

Which current should I use?

Use the welder rated primary current and the nameplate markings required by the applicable rule for the exact welder type.

Are the default factors universally applicable?

No. Verify conductor and protection factors for welder type, duty cycle, installation, group conditions, and adopted NEC edition.

Sources

Verify all markings, sizing factors, conductor conditions, and overcurrent rules against the applicable adopted NEC edition and welder manufacturer documentation.