We are installing a 120/240 volt single phase 100 kW generator. The gen has a maximum output of 417 amps per the manufacturer and is equipped with a 500 amp breaker. The service and the SE rated automatic transfer switch are 400 amp. The conductors from the generator to the transfer switch are 600 kcmil (420 amps). Is the the 500 amp breaker on the generator compliant with the NEC or should it be changed to a 400 amp breaker?