Code Q&A: Types of Motor Controllers

Feb. 23, 2022

Test your knowledge of the NEC.

Courtesy of www.MikeHolt.com.

Based on the 2020 NEC.

Q. What is the NEC definition of a motor controller?

See answer below.

A. The NEC defines a “controller” as any switch or device used to start and stop a motor by making and breaking the motor circuit current [Sec. 430.2 Definitions].

A controller can be a horsepower-rated switch, snap switch, or circuit breaker. A pushbutton that operates an electromechanical relay is not a controller because it does not meet the controller rating requirements of Sec. 430.83. Devices such as start-stop stations and pressure switches are control devices, not motor controllers.

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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.