I am a licensed electrician in North Carolina. Our inspectors are now requiring us to run sized 250kcmil al. to our 200 amp sub panel located on the interior of the house. We are feeding from a 3R, 200 amp meter combo with a 200 amp main breaker to a 225a main lug panel on the inside. The only way to do this is to run conduit to the inside of the house. Is anyone else experiencing this dilema?

What is their basis for requiring this?

310.15(B)(6) is pretty clear on main power feeders, and that the feeder part does NOT need to be larger than the service entrance conductors.

Were you using 4/0 AL for the 200A before?
I see in other online forums that users claim inspectors told them 4/0 AL cable
Is not rated for 200amp and referred them to NEC code 31015.
The next size they are asking, 250 kcmil is the smallest of kcmil unit.
I haven't worked with wires that big, but I am sure it would be a difficult wire
To work with. I hope you bring this issue up with the home owner and ask for
Extra money doing this work.