|MadSci Network: Engineering|
The subject of grounding electrical systems is complex. I recently had my house rewired, and the electricians put in two ground rods: iron bars 10 feet long and a half inch in diameter driven into the ground. In some areas of the world, the ground wire may simply be tied to a water pipe and use the water supply piping to the house as a ground. When you say you put a pipe in the ground, does it have as much surface area in contact with the soil at those two ground rods? It may, since you do measure 110 volts, but if that ground has a high resistance, not a "solid" ground, current flow through it will be restricted. You should be able to measure 110 V from the hot side of an AC outlet to any part of your plumbing system - which is a lot of pipes buried in the ground. Your local utility is using the earth as part of its distribution system. They recommend local grounding as a safeguard against lightning strikes, but without any local ground, your appliances, lights, etc. would work just as well. Your pipe just provides a current path in parallel with the utility's ground system. Power still flows through the Watt-Hour meter to feed your house.
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