On another forum I have asked questions like this of a utility power guy and he had some great info.
As Rick pointed out if you look at NEC 310.17 4/0 copper is 300 to 400 amp rated 4/0 Aluminum is 235 to 315 amp rated.
Not that the POCOs use this table but it gives us an idea what the conductors can carry.
The POCOs know from experience that a service calculated by NEC standards will not draw the amount of load that the service size is.
Ask yourself, have you ever seen the POCOs conductors fail from overload?
The POCOs conductors are outside of the building if for some reason the conductors where to overheat they can not damage anything but POCOs equipment.
I agree its frustrating to pay for and install large conductors only to see them connected to much smaller conductors, but history shows the POCOs and the NESC know what they are doing.
Bob
