NEC 700.27 EXCEPTION - NEC 2011 and later edition

[anbm]

NEC 700.27 Exception: Selective coordination shall not be required between two overcurrent devices located in series if no loads are connected in parallel with the downstream device.

Under NEC 2011, the exception for transformer primary and secondary protection coordination was removed. I assume it is still fallen under new wording above?

 

[don_resqcapt19]

Yes, there is no change in the application of the section for the 2011 NEC. Here is the substantiation and panel comment for that change from proposal 13-202 for the 2011 code.

Substantiation: The intent of selective coordination is to have only the overcurrent device closest to the fault (first upstream device) to open to clear that fault. This prevents unnecessary outages to other loads on the electrical systems.
The exceptions were added as 2 specific examples where no additional loads are affected if a second upstream device also opens. The intent of this proposal is to clarify that so long as no additional loads are affected by the opening of the second upstream device, selective coordination
offers no additional benefit, and should not be required.
Panel Statement: The changes are editorial to improve clarity and not intended as technical changes.