10 sec transfer & 517

[brentp]

Does another NFPA code call for critical & equipment branches to transfer to emergency power within an allotted time?

All I see in 517 is for the Life Safety branch to transfer within 10 seconds. Or, did I miss something?

Thanks,
Brent

 

[charlie b]

Re: 10 sec transfer & 517

You have to include the Life Safety Branch and the Critical Branch.

517.31 (2002 version) states that the ?emergency systems? must transfer to the alternate power source so that all functions are automatically restored within 10 seconds. 517.30(B)(2) limits the scope of ?emergency systems? to ?circuits essential to life safety and critical patient care.? The equipment branch of the essential electrical system does not need to be automatically transferred within 10 seconds.

 

[brentp]

Re: 10 sec transfer & 517

Thanks charlie b!

I missed 517.31.

I was actually looking for equipment branch transfer time when I noticed, what I thought, was the critical transfer time was missing.(something about the appropriate lag time). I don't have my 'book' with me. My mistake.

Now what about the equipment branch?


Thanks,
Brent

[ September 27, 2004, 06:52 PM: Message edited by: brentp ]

 

[charlie b]

Re: 10 sec transfer & 517

517.34(A) talks about having certain loads automatically placed on the generator after ?appropriate time-lag intervals.? Examples are central suction systems and compressed air systems that serve medial functions, sump pumps that are required for the safety of major systems, and smoke control systems. 517.34(B) then talks about having certain loads placed on the generator either automatically or manually. Examples include heating equipment for operating or labor rooms, certain elevators, and hyperbaric and hypobaric facilities (whatever they are :roll: ). The idea is that Life Safety and Critical get first priority, and the equipment branch has to wait until the generator has recovered from its start up and its initial loading.