Whether the fence being energized and tripping the breaker would depend on the conductivity of the soil, I wired a gas station building and another contractor wired the pumps, The soil was rocky and a poor conductor. The pump electricians used the ridgid conduit to the pumps as the equipment ground, The only thing was they used a pvc nipple between the wireway on the outside of the building and the panel inside. They had pulled a spare 20 amp circuit into the wireway, but failed to wirenut it off. the pumps, door frames of the building, anything metal that was not bonded to the service became live to anything that was. There was probably at least 600' of ridgid in the ground, but due to poor soil conductivity, it did not have enough current to trip the breaker. Ground fault protect the circuit and you should be OK