Cindy,
No one can reference the code for more than a #6 to a ground rod. It is all the earth can possibly take for fault (Circular Mil Area/42.25 = 5 second fault rating for a conductor) and is sufficient for equalizing potential which is its intended purpose in our service side system anyway. Unless you are creating a system for the supply side, you never need larger than a #6 to a ground rod and your code quotation is correct. [Linked Image]