This is a residential 400 amp overhead service, this guy has a christmas light display beyond belief. I have not seen the panel but I will call the guy on Monday to go take a look. He is stating one 200 amp breaker feeds one bus and the other 200 amp breaker feeds the other bus, the breakers are tied together. So theoreticaly each ungrounded SEC will never be subjected to more than 200 amps, which is why he arguing that he only needs 2/0. If this had a 400 amp main then it is a no brainer, but the two 200 amp mains is throwing me for a loop.
