Good Morning Sparkster!
OK, the copper line is the municipal supply and is continuous underground as far as I know. The change to plastic occurs on the building side of the GEC connections (about 18" of copper before the changeover)and the building plumbing is for the most part plastic. The padmounts are on the back side of the building - opposite of the street with the watermain. There is also a metal sprinkler riser in the same room that is not bonded (which needs to be) but that doesn't change the basic question about the GEC connections.
There are other buildings across the street but we're talking 75-100 ft or so in all directions. HV to the 2 padmounts comes in from the street underground.
By the way, the 4/0 AL GEC is OK size-wize for the service conductors.
