Code Quiz of Day

Overcurrent Device Ratings for Welders

Aug. 12, 2014

Article 630 covers apparatus for electric arc welding, resistance welding, plasma cutting, and other similar welding and cutting process equipment that is connected to an electrical supply system.

Mike Holt

Each resistance welder shall have an overcurrent device rated or set at not more than _____% of the rated primary current of the welder.

a) 80
b) 100
c) 125
d) 300

See answer and applicable Code reference

The correct answer is: d) 300

Article 630 covers apparatus for electric arc welding, resistance welding, plasma cutting, and other similar welding and cutting process equipment that is connected to an electrical supply system. As noted in Sec. 630.32(A), "Each welder shall have an overcurrent device rated or set at not more than 300% of the rated primary current of the welder. If the supply conductors for a welder are protected by an overcurrent device rated or set at not more than 200% of the rated primary current of the welder, a separate overcurrent device shall not be required."

About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.