Code Q&A: Grounding Requirements for a Building

May 27, 2021

Test your NEC knowledge.

Based on the 2020 NEC.

Q. What is the Code rule for connecting a grounding electrode system to a building supplied by a feeder?

See answer below.

A. As per Sec. 250.32, a building supplied by a feeder must have a grounding electrode system and a grounding electrode conductor installed in accordance with Part III of Art. 250.

Exception: A grounding electrode is not required for a building if it is supplied by a single branch circuit or multiwire branch circuit.

CAUTION: To prevent dangerous objectionable neutral current from flowing on metal parts [Sec. 250.6(A)], the supply circuit neutral conductor is not permitted to be connected to the remote building disconnect enclosure [Sec. 250.142(B)] (Figure above).

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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.