NEC 517.31 versus 700.10(5)

[Shujinko]

I have a project in a Hospital with an Essential System Switchboard fed from a generator. Looking at one of the distribution sections in the switchboard we have feeder breakers for the life safety branch, critical branch, fire pump for the hospital, and another feeder breaker for the Emergency branch for an attached Medical Office Building. Are these all allowed to be in a same distribution section? 517.31 says the separation of the essential system branches happens at the transfer switches. The transfer switches are downstream of the switchboard. However, 700.10(5) says this separation needs to happen at the Switchboard. Which one is correct?

 

[packersparky]

I have a project in a Hospital with an Essential System Switchboard fed from a generator. Looking at one of the distribution sections in the switchboard we have feeder breakers for the life safety branch, critical branch, fire pump for the hospital, and another feeder breaker for the Emergency branch for an attached Medical Office Building. Are these all allowed to be in a same distribution section? 517.31 says the separation of the essential system branches happens at the transfer switches. The transfer switches are downstream of the switchboard. However, 700.10(5) says this separation needs to happen at the Switchboard. Which one is correct?

See 517.26. The separation for healthcare facilities begins at the transfer switch per 517.31(A).

517.26 Application of Other Articles​

The life safety branch of the essential electrical system shall meet the requirements of Article 700, except as amended by Article 517.