A few years ago, we had a utility pole rot out from termites. On my place there is a pole that carries 12k and 220 on it. Both are non insulated. Well, the 12 k got into the 220 to the house, it melted off the ground rods, three, copper, and the ground to the water pipe. Melted off the pipe!! BUT no damage inside except one thing. A paper shredder. SDGE replaced that... Good grounds a must...