National Electrical Installation Standards

Standards as High as Your Own

 
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Tuesday, December 26, 2023

Question:

Good morning CQD, in the 2023 edition of the NEC® the informational note Figure to Section 700.32(C) states that OCPD-B is not required to selectively coordinate with OCPD-A because OCPD-B is not an emergency system OCPD. Doesn't new section 240.11 require OCPD-B to be selectively coordinated with the service OCPD-A? All the best, William G
A

Answer:

Hi William, great question. In the Informational Note/Figure to 700.32, OCPD-B would not be required to be selectively coordinated with OCPD-A. OCPD-B does not require selective coordination as it is not an emergency system requiring selective coordination by Section 700.32, as such Section 240.11 does not apply. The purpose of selectively coordinating OCPDs is to achieve a higher level of reliability by localizing outages. In the one-line diagram in the Figure provided in Section 700.32, if either one or both of OCPD-A or OCPD-B trips, the result in outage would be the same.

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