Code Q&A

Q.When is a two-pole breaker required for a multiwire branch circuit? A.Multiwire and multiple branch circuits that supply devices or equipment on the same yoke (also called a strap) must be provided with a means to disconnect simultaneously all ...

Mike Holt

Oct. 7, 2005

Q.When is a two-pole breaker required for a multiwire branch circuit?

A.Multiwire and multiple branch circuits that supply devices or equipment on the same yoke (also called a strap) must be provided with a means to disconnect simultaneously all ungrounded conductors that supply those devices or equipment [210.4(B) and 210.7(B)]. Individual single-pole circuit breakers with handle ties identified for the purpose — or a breaker with common internal trip — can be used for this application [240.20(B)(1)].

Note: The intent of this rule is to prevent people from working on energized circuits that they thought were disconnected from their source.

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.