Tip of the Week: Branch Circuits, Part 1

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.

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