Emergency Generator Question

[faresos]

I have a situation where we have 1000A service and the owner wants to back up the whole building. Our approach is to provide a service -entranced ATS a head of the main switchboard. The question is, do I still need to provide a second transfer switch for emergency lighting even though the whole building is backed up by the emergency generator? Any thought will be appreciated.

Thanks in advance.

 

[hillbilly1]

Is the exsisting emergency lighting on generator at present? Or are they battery backup? If they are battery backup, then no, you would not have to put them on a seperate transfer switch......but you will have to maintain the battery backup function. If they are already on an exsisting generator, it can remain as a redundant system or if possible, use the exsisting t-switch with a seperate breaker and feed from the new generator.

 

[ceb58]

You first need to find out if this is truly an emergency system or is just an optional system. Look at 700.1 fpn# 3

 

[erickench]

Take a look at NEC 700.6(D). An emergency power source may supply other loads but the transfer equipment used for emergency power may not supply any loads but emergency loads.

 

[hillbilly1]

Take a look at NEC 700.6(D). An emergency power source may supply other loads but the transfer equipment used for emergency power may not supply any loads but emergency loads.

Since this is an exsisting building, there should already be a backup for emergency loads, this would be a redundant system. As long as the exsisting system is maintained, and no other emergency loads are added (Such as a fire pump, or other life safety systems) this would be considered an optional standby system. But.....if the exsisting backups for the emergency systems are abandoned or more systems added, then 700.6(D) would apply.