Emergency Systems with Multiple ATS

Status
Not open for further replies.
T

teh_engineer

Member
Location
Baltimore, MD
We are designing a building that has the following requirements:
- A generator sized to cover the entire 3P, 120/208V 800A service
- Same generator is to provide power for the life safety system
- Same generator is to provide power for critical equipment, which also has a UPS


Based on my understanding of NFPA 110, a separate ATS is required for the life safety system (designated ATS-LS) as the EPSS must be independent.


Are there any issues with having one ATS (designated ATS-MAIN) cover the entire 800A distribution panel (which also provides normal power for the life safety and critical equipment paths) in addition to two more ATS (one for life safety and one for critical equipment) between the generator and the associated panels?


My understanding is that it's similar to having a UPS with an ATS, as the UPS would switch first, then switches to the standby source once the associated ATS kicks in. So similarly, ATS-LS would switch first and stay on the standby source, then ATS-MAIN switches over, but ATS-LS would never switch back until normal power is restored.


Thanks in advance
 
J

jeremy.zinkofsky

Senior Member
Location
nj
teh_engineer said:
We are designing a building that has the following requirements:
- A generator sized to cover the entire 3P, 120/208V 800A service
- Same generator is to provide power for the life safety system
- Same generator is to provide power for critical equipment, which also has a UPS


Based on my understanding of NFPA 110, a separate ATS is required for the life safety system (designated ATS-LS) as the EPSS must be independent.


Are there any issues with having one ATS (designated ATS-MAIN) cover the entire 800A distribution panel (which also provides normal power for the life safety and critical equipment paths) in addition to two more ATS (one for life safety and one for critical equipment) between the generator and the associated panels?


My understanding is that it's similar to having a UPS with an ATS, as the UPS would switch first, then switches to the standby source once the associated ATS kicks in. So similarly, ATS-LS would switch first and stay on the standby source, then ATS-MAIN switches over, but ATS-LS would never switch back until normal power is restored.


Thanks in advance
Click to expand...

So you want to connect the life safety and critical ATS' to the output of the main ATS? A schematic would help here.
 
Status
Not open for further replies.
Top