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Monday, October 10, 2022
Question:
Hello Code Friends, I am a retired Electrical Inspector (over 20 yrs.) and was the VP & member of the IAEI of WNY for over 40 yrs. Now the question, In the community that I now live in Florida, we have a major seawall project going on. I am the liaison between the contractors and the Co-Op owners. There was a "Sub Panel" used for feeding the boat docks on one section of this project. It was relocated away from the water to a unistrut structure, with new conduits re-feeding the docks. This new load center "sub-panel" is fed from a 200A 4-wire 1ph meter- main. I told the electrician on site that the new sub-panel requires a new grounding electrode and ground rod. He disagreed, so I installed it myself prior to installation of the panel. I believe that I am correct according to the Soars Grounding Book and the NEC Code. What is your interpretation?
Al MacKenzie
A
Answer:
Hi Al, thank you for your contributions to the Electrical Industry as both an Electrical Inspector, and as a leader/long-time member of the IAEI. This has often been a point of debate in the electrical code world. Section 250.32(A) of the 2017 NEC™️ specifies that Buildings and Structures supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The debate was often over what is considered a "Structure". The Code defines a Structure as "That which is built or constructed, other than equipment". The words "other than equipment" were added to the definition of Structure in the 2017 edition, with the intent of adding clarity. In the situation you describe in your question, the unistrut meets the definition of a "Structure", therefore a grounding electrode would be required at that feeder mounted to the unistrut structure.