My take on your installation is this:
1. The GEC must be sized per 250.66
2. Although it must not be spliced, it may be tapped onto by the GEC from each 200 amp panel.
3. I would connect it into one panel and then run a # 4 from the 2nd panel to tap onto it.
4. The #6 GECs should also be able to just tap onto it.
Disclaimer--
as always, if there is significant costs invloved , check with AHJ first!
[This message has been edited by Redsy (edited 09-19-2002).]
