Code Q&A: Sizing Branch Circuits for Appliances

Dec. 9, 2021

Test your Code knowledge.

Based on the 2020 NEC.

Q. What is the Code requirement for branch circuit sizing for appliances?

See answer below.

A. The ampacities of branch-circuit conductors for an individual appliance are not permitted to be less than the branch-circuit rating marked on the appliance (Sec. 422.10). Author’s Comment: Listed appliances come with installation instructions from the manufacturer, and sometimes the minimum overcurrent protection and or conductor size are marked on the appliance.

Branch-circuit conductors for household ranges and cooking appliances are sized per Table 220.55 and Sec. 210.19(A)(3).

Branch circuits supplying appliances in addition to other loads must be sized per Sec. 210.23(A) as follows:

A 15A or 20A branch circuit cord-and-plug-connected equipment is not permitted to be rated more than 80% of the branch-circuit ampere rating [Sec. 210.23(A)(1)].
A 15A or 20A branch circuit equipment fastened in place is not permitted to be rated more than 50% of the branch-circuit ampere rating, if the circuit supplies both luminaires and receptacles [Sec. 210.23(A)(2)].

These materials are provided to us by Mike Holt Enterprises in Leesburg, Fla. To view Code training materials offered by this company, visit www.mikeholt.com/code.

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.