Customer has 200amp OH service w/ 2 100amp meters(double gang meter) feeding 2 100amp panels w/100amp main breakers.Customer wants one panel to be up graded to a 200amp.So the end result would be a 200amp & 100amp panel. I would think I would have to upgrade to a 2 gang 200amp meter box.The house has gas heat and appliances. The load calculation on the house isnt changing by a large amount. Just needs more breaker space for attic renovation.That said ... the 200amp OH service should be ok.. any input is greatly appreciated..ToHo