?
Friday, February 12, 2021
Question:
Comments on Code Question of the Day and response for February 8, 2021:
RE: CQD 02/08/2021
547.5(F) makes no reference to the conductor material, only that if “not part of a listed cable assembly, . . . . , it shall be insulated.” Matthew Hermanson
RE: CQD 02/08/2021
Concerning the question from Monday, February 8, 2021 and the underground feeder to a farm building, I would like to offer a different perspective. Section 547.5(F) does not require a separate equipment grounding conductor (EGC). This section starts off by saying, “where a separate EGC is installed…” Generally, this section does call for an insulated EGC. However, for the 2020 NEC, CMP-7 added language to 547.5(F) to recognize the use of underground cable assemblies such as Type UF cable. With the use of this type of listed cable assembly, the enclosed EGC is not “insulated.” The EGC may be covered, but it is not by definition “insulated.” Also, 547.5(F) does not require the EGC of an underground feeder to be copper. During the 2014 NEC revision cycle, CMP-19 (now CMP-7) allowed the use of copper, aluminum, or copper-clad aluminum conductors for the underground EGC. At the time, this EGC required by 547.5(F) for underground use had to be insulated or covered; therefore, the metal used inside the insulated material was ruled to be irrelevant since the conductor is protected by this insulation. The 2020 NEC requirements of 547.5(F) reiterate this fact by not specifying or limiting this underground EGC to only one conductor material. Regards, L. Keith Lofland – Chairman-CMP-7
A
Answer:
Thanks for the additional comments from Keith and Matthew to clarify the response. Yes, a separate equipment grounding conductor is not required, but where installed it must meet the requirements of 547.5(F). Thanks for that follow up participation and keeping us on our toes and making sure the information is correct. Appreciate the heads up on 2023 NEC developments too.