Ecmweb 1748 230 24ax3 Un230 11web
Ecmweb 1748 230 24ax3 Un230 11web
Ecmweb 1748 230 24ax3 Un230 11web
Ecmweb 1748 230 24ax3 Un230 11web
Ecmweb 1748 230 24ax3 Un230 11web

Code Q&A

Aug. 27, 2007
What is the minimum service drop clearance above a roof?


Q. What is the minimum service drop clearance above a roof?

A. In general, overhead service conductors must maintain a minimum vertical clearance of 8 feet above the surface of a roof for a minimum distance of 3 feet in all directions from the edge of the roof [230.24(A)]. If the slope of the roof exceeds 4 inches for every 12 inches, 120/208V or 120/240V conductor clearances can be reduced to 3 feet over the roof [230.24(A) Ex 2].

If the service mast is used in a through-the-roof application, 120/208V or 120/240V conductor clearances can be reduced to 18 inches over the overhang portion of the roof [230.24(A) Ex 3]. There must not be more than 6 feet of service-drop conductors over the overhang portion of the roof and the service mast can’t be located more than 4 feet from the edge of the roof overhang measured horizontally.

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.

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