Unless your house is total electric, you likely don't need a 48 kw generator. A generator that will handle the full 200 amps and the transfer switch is going to be realy pricey.
One of my customers has a 7000 sq ft house & the generator is 12kw if I remember correctly. We have it wired to a 200 amp panel & it is up to him which loads he wants to run during a power outage. Instead of using a 200 amp transfer switch, we used an interlock kit that allowed him to feed the panel with a smaller two pole breaker.
To size your generator, decide what loads you feel must absolutely be on and then if that number idoesn't breeak the bank add the loads that it would be nice to have & that would be the size generator you need.
