Code Quiz of Day

Grounding Electrode Burial Depth Requirements

April 13, 2015

Part III of Article 250 focuses on the grounding electrode system and grounding electrode conductor requirements

Where rock bottom is encountered when driving a ground rod at an angle up to 45 degrees, the electrode can be buried in a trench that is at least ______ deep.

a) 18 in.
b) 30 in.
c) 4 ft
d) 8 ft

See answer and applicable Code reference

The correct answer is: b) 30 in.

Article 250 covers the requirements for bonding and grounding. Part III of this Article focuses on the grounding electrode system and grounding electrode conductor requirements. As noted in 250.53(G), "The electrode shall be installed such that at least 8 ft of length is in contact with the soil. It shall be driven to a depth of not less than 8 ft except that, where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or, where rock bottom is encountered at an angle up to 45 degrees, the electrode shall be permitted to be buried in a trench that is at least 30 in. deep."

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.