Code Quiz of Day

Using an Underground Metal Water Pipe as a Grounding Electrode

May 15, 2015

Part III of Art. 250 focuses on the grounding electrode conductor and grounding electrode system.

In order for a metal underground water pipe to be used as a grounding electrode, it shall be in direct contact with the earth for ______.

a) 5 ft
b) 10 ft or more
c) less than 10 ft
d) 20 ft or more

See answer and applicable Code reference

The correct answer is: b) 10 ft or more

Part III of Art. 250 focuses on the grounding electrode conductor and grounding electrode system. As per Sec. 250.52(A)(1), "A metal underground water pipe in direct contact with the earth for 10 ft or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductor(s) or jumper(s), if installed."

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.