Generator at service question

[Mddocstanley]

Here are the facts:
Objective is to replace the manual transfer switch with an automatic one.
Normal power at service is 480/277v at 200a 3ph fused at 200amp in 3R disconnect immediately at where the existing service entrance rated manual transfer switch is located just on the inside. Txfer switch is fused on both normal and alternate power at 200amps. All conductors on and in the building service equipment are 3/0 cu.
Alternate power is 140kw 480/277v with @214amp output with a 250amp internal breaker. A 4/0 W type cable feeds from the gen. to a pin & sleeve 200amp receptacle on the exterior of the building immediate to where the service rated manual txfer switch is on the inside.
I have asked about changing the gen breaker to 225amp rating and it is not UL designed for the 225amp I am told.
Can I upgrade the conductor on the load side of the Pin and sleeve receptacle to 4/0 cu thhn and on through a non service entrance rated AUTOMATIC Txfer switch to the main switchboard, and meet code?
My thinking is that I have to have an OCPD (fused disconnect) on exterior, but then I cannot incorporate the receptacle into the system, which may be ok and will probably wind up doing anyway.
Thanks for any and all input,
MD

 

[ceb58]

Here are the facts:
Objective is to replace the manual transfer switch with an automatic one.
Normal power at service is 480/277v at 200a 3ph fused at 200amp in 3R disconnect immediately at where the existing service entrance rated manual transfer switch is located just on the inside. Txfer switch is fused on both normal and alternate power at 200amps. All conductors on and in the building service equipment are 3/0 cu.
Alternate power is 140kw 480/277v with @214amp output with a 250amp internal breaker. A 4/0 W type cable feeds from the gen. to a pin & sleeve 200amp receptacle on the exterior of the building immediate to where the service rated manual txfer switch is on the inside.
I have asked about changing the gen breaker to 225amp rating and it is not UL designed for the 225amp I am told.
Can I upgrade the conductor on the load side of the Pin and sleeve receptacle to 4/0 cu thhn and on through a non service entrance rated AUTOMATIC Txfer switch to the main switchboard, and meet code?
My thinking is that I have to have an OCPD (fused disconnect) on exterior, but then I cannot incorporate the receptacle into the system, which may be ok and will probably wind up doing anyway.
Thanks for any and all input,
MD

I would not touch the gen. breaker The mfg. seems to have complied with 445.13. Conductors size to name plate plus 115% to first OC device. 214amp* 115%= 246amp up size to next standard breaker 250amp.
As far as a disconnect you must have one 225.32. And no the breaker on the gen set will not comply unless it meets 225.36, 445.18 and the with in sight rule.
My concern would be you stated you have a 200 amp rated receptacle and what rating is your transfer switch? Your disconnect that is requried by 225.32 could be fused at 200amp to match the rating of the equipment.