National Electrical Code

Code Q&A

March 8, 2005

Q. Must metal siding and metal framing members be grounded? A. The NEC doesn’t specifically require metal siding or metal framing members to be bonded (not grounded) to an effective ground-fault current path . However, exposed structural metal that ...

Mike Holt

Q. Must metal siding and metal framing members be grounded?

A. The NEC doesn’t specifically require metal siding or metal framing members to be bonded (not grounded) to an effective ground-fault current path [250.4(A)(4)]. However, exposed structural metal that forms a metal building frame must be bonded to one of the following (effective ground-fault path) [250.104(C)]:

• Service equipment enclosure
• Grounded neutral service conductor
• Grounding electrode conductor sized in accordance with Table 250.66
• One of the electrodes of the grounding electrode system

The bonding jumper for structural metal is sized to the conductors that supply the building or structure, in accordance with Table 250.66. In addition, the bonding jumper must be:

• Copper, where within 18 inches of earth [250.64(A)]
• Securely fastened and not exposed to physical damage [250.64(B)]
• Installed without a splice or joint, unless spliced by compression connectors or by the exothermic welding process [250.64(C)]

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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.