I'm installing a 1000 amp service, and I plan on using ground rods and the water main for my grounding electrode system. I'm using 4x parallel 250 kcmil per phase. According to Table 250.66, I'd be looking at a 2/0 grounding electrode conductor, if I'm not mistaken. My question is, how do I go about attaching such a large conductor to the ground rods and water main? I asked my electrical supplier and they didn't have a quick answer, which makes me wonder if I've sized the conductor wrong. Also, do I need larger ground rods for such a large conductor?