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Re: transfer switch #20879 01/25/03 02:50 PM
Joined: Jun 2001
Posts: 196
Cindy Offline OP
thank you for your thoughts on this, i'll be looking at the calcs and job site this next week.

but from the 1-line it looks wrong that the 800a s-board that was fed with 8-350's is now going to be fed from a 225a main breaker
for the whole system and 4/0 coppers to feed 3 panels rated 300a, 300a, and 200a. how can the designer do that? [not to mention the size issue of landing them/don's question]

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Re: transfer switch #20880 01/25/03 11:32 PM
Joined: Jun 2001
Posts: 642
nesparky Offline
I would look very closely at the load calcs. Also check with the poco and see what the historical load/month has been. This may have been over built for a future expansion that did not occur. I suspect that those areas will most likely have the answers-if the designer did not screw up his/her load calcs.
Sometimes owners want to do things as cheaply as possible an try to hard to save money. If designers cannot or will not tell- them sorry that will not work- you get drawings that are questionable.
Good luck on this job

[This message has been edited by nesparky (edited 01-25-2003).]

Re: transfer switch #20881 01/25/03 11:53 PM
Joined: Mar 2002
Posts: 582
Ron Offline
It is a code violation to have a 225A main serving a 300A distribution breaker, since they can never be coordinated.

Re: transfer switch #20882 01/26/03 01:36 PM
Joined: Jun 2001
Posts: 196
Cindy Offline OP
>>>It is a code violation to have a 225A main serving a 300A distribution breaker, since they can never be coordinated.<<<

i know i'm going to sound stupid, but where does it say that? 240.12 tlaks about coordination for orderly shutdown, 110.10 says to cordinate to rpotect equipment. but i dont see why a smaller ocpd cant protect larger ocpd's or equipment. inconvenient to the user, but is it a violation? thanks

Re: transfer switch #20883 01/26/03 01:47 PM
Joined: Nov 2000
Posts: 2,148
resqcapt19 Offline
What code section requires OCPD coordination for general occupancies?

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