Is a disconnect required to be installed next to a transfer switch (industrial, campus type setting) for the generator feeder. There is a generator remotely installed away from a Bldg. and the generator power enters a mechanical room. Normally, I've seen the gen. feeder go right to the transfer switch. I think it's good design, in case you want to isolate Generator power for a test, and or trouble shooting job.
Is there anything in the code that requires such a disconnect? Thanks

445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with disconnect(s) by means
of which the generator and all protective devices and control
apparatus are able to be disconnected entirely from
circuits supplied by the generator except where both of
following conditions apply:
(1) The driving means for the generator can be readily
down.
(2) The generator is not arranged to operate in parallel
another generator or other source of voltage.

Most/All generators have a main breaker in the generator, this serves as the disconnecting means for the feeder to the transfer switch.