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Wednesday, June 7, 2023
Question:
Hello Code Friends. We have an installation where the electric service installed on the house has a concrete encased electrode (Ufer ground) as one of the electrodes. We are installing a 4-wire feeder out to the newly built detached garage to a sub-panel containing 8 breaker spaces. The detached garage is built on a slab with a poured foundation, and no rebar was left exposed for connection a ground connection. Does the detached garage require a concrete encased (Ufer ground) electrode connection? Is it exempt from the Ufer Ground because the foundation is poured, and no rebar is exposed? Thanks for the information, Paul Winger
A
Answer:
Hello Paul, great question. Yes, a building or structure supplied by a feeder is required to have a grounding electrode system in accordance with Section 250.50. Additionally, any of the electrodes present at the garage listed in Section(s) 250.52(1)-(7) must be bonded together to make up the grounding electrode system. Based on the information in your question, it sounds like there is rebar present in the poured foundation of the garage, and therefore a concrete encased electrode as specified in Section 250.52(3) must be used as part of the grounding electrode system.