I am upgrading a residential service from 200A to 320A. There is existing 200A main breaker panel, and I installed a new 200A main breaker panel next to existing. My question is for my grounding I will have to upsize to #2 for my water main and leave the #6 to ground rod. Can I jump from new panel to existing panel with #2 and tie to ground or do I have to run to waterline with another separate #2 and run to ground rod with another #6?
