Busbar rating 8000a

[m sleem]

I'm in a project where i have two generators in emergency system each 2500kva, 400v, the paralleling switchgear's main bus is 8000a, my understanding is UL allows up to 5000a, so i was thinking that i'm out of the UL in this part, today i had a meeting with a Asco ATS's representative, he presents a paralleling switchgear with busbar capacity up to 10,000a, i'm not aware of the UL standard, but do we have an exception for the emergency system?

 

[vicdog]

If you think about how the gear will be connected, try to determine current flow on each piece of the bus. I doubt you will need even 5000 amp bus.

 

[ron]

As mentioned, if you distribute the in's and out's across the SWGR, you likely do not need 10kA.

UL SWGR and SWBD horizontal bus bar can be oriented to be larger than 5kA. The breakers might only be up to 5kA, but think of the load flow paths.

 

[m sleem]

If you think about how the gear will be connected, try to determine current flow on each piece of the bus. I doubt you will need even 5000 amp bus.

Yes, that's true if the busbar is splitted into three or four pieces.

 

[m sleem]

As mentioned, if you distribute the in's and out's across the SWGR, you likely do not need 10kA.

UL SWGR and SWBD horizontal bus bar can be oriented to be larger than 5kA. The breakers might only be up to 5kA, but think of the load flow paths.

By the way, do we have a limitation for the busbar's rating of a one piece?