system grounding size

[Toros]

HI ,
my fried contractor installs a system-grounding for the new 600A service;
3/0 cu to the cold water pipe
but we do not know what size ?????? for ground Rods


Thank you

 

[LarryFine]

but we do not know what size ?????? for ground Rods

Rods never require greater than #6 cu,