I have a dry type transformer about 100 feet away from the building it is serving (pump house). We have a panel inside the building. A metal water pipe enters the building from underground up through the slab about 30 feet from the panel, roughly in the middle of the building. How would you route the grounding electrode conductor to the waterpipe: exposed, rmc, pvc etc? The grounding electrode conductor to the water pipe may be 60 feet long, is there a limit to how long the GEC could be?