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Wednesday, October 12, 2022
Question:
CQD,
Thank you for the thoughtful and insightful service you provide to the industry. My question pertains to 250.32(B) and the conductor between the equipment grounding conductor (EGC) "run with the supply conductors," and the grounding electrode. A separate building is supplied by a feeder and has a single building disconnect. The grounding electrode is a concrete-encased electrode with rebar stubbed up. Is the conductor from the equipment grounding bus in the disconnect to the grounding electrode the EGC as stated in the citation and sized according to 250.122; or is the conductor considered a grounding electrode conductor and running from the grounding electrode to the equipment grounding bus sized according to 260.66?
Thank you,
Claudia
A
Answer:
Claudia, thank you for the kind words regarding the CQD. Your question brings to light the importance of using proper terminology when applying Code requirements. A Grounding Electrode Conductor is defined in Article 100 as A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.
A Grounding Electrode is defined in Article 100 as A conducting object through which a direct connection to earth is established.
Based on those two definitions, the conductor installed between the single building disconnect grounding bus, to the concrete-encased electrode, would in fact be a Grounding Electrode Conductor.
Section 250.66 states that the size of a Grounding Electrode Conductor installed at each building supplied by a feeder, shall not be less than the size given in Table 250.66.