Re: service upgrade required?
Not according to NEC 690.64(B)(2). Here is what the section says for commercial applications:
a 100amp panel can easilly go 125amps
If a commercial installation panel / busbar rated at 100 A, and itís supplied from the grid via a 100 A breaker, then no other power sources (i.e., PV and inverter) can be connected to the panel as a power source.
The sum of the ampere ratings of overcurrent devices in circuits supplying power to a busbar or conductor shall not exceed the rating of the busbar or conductor.
The reference NEC article includes a 120% exception for residential applications. For example, if a 100 A panel / busbar is supplied from the grid via a 100 A breaker, then another power source can be connected via a 20 A breaker.
So, the NEC limit would be 120 A on a 100 A panel / busbar for residential applications.
Jim / crewzer
120618: System off-line for a while...