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Tip of the Week: Branch Circuits, Part 1

Jan. 16, 2018
Guidance to help you avoid violating the National Electrical Code in branch circuit installations.

These tips will help you avoid National Electrical Code (NEC) violations in your branch circuit installations.

  • Some kinds of branch circuits have special requirements that amend or replace those in Art. 210. These include air conditioning equipment, busways, heaters of various types, and motors. You’ll find a complete list of specific purpose branch circuits in Table 210.3.
  • All conductors of a multi-wire branch circuit must originate from the same distribution equipment, (e.g., panel) [Sec. 210.4(A)].
  • A multi-wire circuit is on that consists of two or more ungrounded conductors that have a voltage between them. But to fit the definition, it also must have a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit. That grounded conductor also must be connected to the neutral or grounded conductor of the system [Art. 100].
  • Each multi-wire branch circuit must have a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates [Sec. 210.4(B)]. This role is typically played by a circuit breaker, and there is only one circuit per breaker. So we can think of a circuit breaker as defining the branch circuit.
About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.

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