Earthing?

[Robin Hewitt]

Earth loops are always trying to sneak in and act like shorted out transformers. For example, an AC electric motor has an earth connection that goes to it's casing and that casing connects to the machine body which has a seperate ground connection. That is an earth loop with some major magnetic field activity in one corner and current starts to flow. Not only does the motor earth wire heat up but so do any other loops in the system, especially if they pass through the machine body. The Volts may be low but the current can be enormous.