if you are feeding a 2 gang meter base with 4/0 copper for two 200 amp panels can you run number 4 wire from each of the panels to the water line for grounding since they are 200amp each or must you run a number 2 from each panel
You can run one GEC and tap off to each panel/service disconnect. The tap/bonding jumper will be sized according to your #4/0 from the meter to the panel. The GEC will be sized according to the SEC's supplying your 2 gang meter base.