Code Q&A: Protection of Dwelling Unit Services

Nov. 5, 2020

Test your NEC knowledge.

Mike Holt

Based on the 2020 NEC

Q. What is the Code requirement for surge protection of dwelling unit services?

See answer below.

A. The requirements are outlined in Sec. 230.67 of the NEC.

230.67 Surge Protection

(A) Surge-protective Device. All services suppling dwelling units must be provided with a surge protective device.

(B) Location. The surge-protective device must be an integral part of the service disconnect or be located immediately adjacent to the service disconnect.

Exception: The surge-protective device is permitted to be located in the downstream panelboard.

An example of where the exception could be applied is where there is an exterior meter main that feeds an interior panel. The surge-protective device could be installed at the interior panel using the exception.

See Parts I and II of Art. 242 for the installation requirements that apply to surge-protective devices.

(D) Replacement. Where service equipment is replaced, surge protection must be installed.

These materials are provided to us by Mike Holt Enterprises in Leesburg, Fla. To view Code training materials offered by this company, visit www.mikeholt.com/code.

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.