We keeping debating what defines a service entrance per NEC. Take a typical large facility with multiple buildings . We purchase power and then it goes through our transformers, distributed across the facility and more transformers to lower the voltage again. Is the service enterance where we take ownership or the secondary of every transformer?

I agree. The service begins where the utility feeders end. Stop and think, the utility is not obligated to follow NEC. But your distribution on your campus is.

So the first disconnecting means AFTER the POINT OF SERVICE is your SERVICE DISCONNECT. Main disconnects after the transformers fed by this SERVICE DISCONNECT are not SERVICE DISCONNECTS. Are you interested in identifying the SERVICE DISCONNECTS for grounding purpuses?

Services can be low voltage or high voltage (NEC definition) depending how you obtain your supply from the local utility. At our plant, we receive 115kV service and then transform and distribute within our customer owned distribution system. The NEC handbook has some good explanation of this distinction for campus styled multibuilding complexes in Art 90.2, 225.32, and 695.3 (C). The definition of service has changed over the years and many older engineers and electricians still use the old definitions. I have attached a few docs I developed to help explain services to my workforce. They may be of use to you also.