and I have a question about the possible shock hazzard of touching the grounded surface of a system during the instant of a ground fault. If you have energized the bonded metal parts (with what ever potential) and you touch this metal. What will you also have to touch or be in contact with to be a path for current to flow on? certainly if you touch another bonded metal object it's not likely to be of a substantially different potential that the metal you're touching in the first place. And if you are a parallel path, your own resistance is likely to be so much greater than the bonded metal parts that there isn't much of a hazzard. And then the overcurrent protection opens the circuit.