emergency system feeders

[Bill Endicott]

We have three emergency/essential system parallel feeders (critical, life safety and equipment) traveling to three different transfer switches for a Hospital upgrade. Is it required to keep these three different feeders (critical, life safety and equipment) separate/isolated when traveling through a pull box prior to terminating at the transfer switches?

 

[LEO2854]

We have three emergency/essential system parallel feeders (critical, life safety and equipment) traveling to three different transfer switches for a Hospital upgrade. Is it required to keep these three different feeders (critical, life safety and equipment) separate/isolated when traveling through a pull box prior to terminating at the transfer switches?

Are they in 3 separate Pipe runs and just passing through the box?

Welcome to the forum..

 

[RUWired]

We have three emergency/essential system parallel feeders (critical, life safety and equipment) traveling to three different transfer switches for a Hospital upgrade. Is it required to keep these three different feeders (critical, life safety and equipment) separate/isolated when traveling through a pull box prior to terminating at the transfer switches?

Yes it is required to keep separate from each other. See 517.30(C)1(2014 edition)

 

[MEP_PM]

We have also had this discussion specifically on the feeders from separate breakers at a generator that run to two ATS. Specifically where does the Critical and Life Safety Branches start? In our situation, we were relocating a generator which required us to intercept the underground feeders. We were trying to determine if we could install one large underground box or needed to installed two boxes to keep the feeders separate.

Based on NFPA 99 (2012) 6.4.2.2.1.2 "The division between the branches shall occur at the transfer switch...". So, I think one box could have been used but we installed 2 box to ensure there wasn't an issue.