They are switching the neutral because on a service that size you would have GFI protection on the service. The generator is to be treated as a separately derived system 250.35 (A) . The N & G will be bonded at the generator , just like your main service. From there you have your phase conductors and EGC to the ATS. The EGC's from the service and generator will be bonded in the ATS with the neutrals now separated and isolated by the switch. Just remember now all OCD's down stream of the ATS are now considered a sub panel and the N - G must be separated and isolated from each other.
Originally Posted by hraus
Organized people are people that are just too lazy to look for their stuff