Service grounding

[moresi]

Working on a three family home where present service is 3 - 100 amp breaker panels that all have a #6 CU running individually to a ground rod and 3 individual runs to water meter. I know this is wrong and will be correcting it. I am installing a house panel on a new single bypass socket and locating a panel adjacent in basement to existing ones. I should be jumping from panel to panel with #6 CU for rods and #4 CU for meter correct? Do I go with larger ground size due to fact that 4/0 AL goes to existing 3 gang meter pan?
How about in a scenario where I have two 200 amp panels side by side fed from a 400 amp socket? Thanks - I should have taken a photo of all those ground wire runs - will make for some good copper scrap.

 

[Dennis Alwon]

Working on a three family home where present service is 3 - 100 amp breaker panels that all have a #6 CU running individually to a ground rod and 3 individual runs to water meter. I know this is wrong and will be correcting it.

How are you changing this and why do you think this is wrong

 

[moresi]

I think that I may have posted this question in haste. I always had done installs where the grounding conductor would run from one panel to the next in multiple panel situations and then to the electrode. I looked further into this (after posting my question) and now understand this to be acceptable but the preferred method is to have seperate runs from each panel. So I guess my only question is what is your preferred method of grounding multiple panels when doing a 2 panel plus service? Do you size according to the rating of the biggest ungrounded conductor feeding the panels or the ganged meter enclosure?