Quote
If the 2/0 is thhn you will have no problem

THHN is not permitted in underground raceways.

You may have dual rated THHN/THWN which can be used underground but the ampacity will be based on THWN (75 C) along with the fact that the 90 C column is only useful for ampacity adjustments.

You will not find any terminals rated 90 C so you can not run the wire at the 90 C rating.

All of this does not matter as you can as Roger pointed out use table 310.15(B)(6) which allows 2/0 cu for a 200 amp service. [Linked Image]

Bob Badger
Construction & Maintenance Electrician
Massachusetts