A ground loop is also what exists when you hear a hum in your stereo equipment
. When multiple electronic device
s are connected to the same electrical supply, current
can leak from one device to another if there is no clear path to ground
It can be cured by ensuring that every device in the system has a clean, solid path to a common ground. In a car, this means that every device needs a ground wire going to shiny bare metal somewhere on the car body that is at least as thick as the wire providing power. In the home, if your power amp or receiver doesn’t have a three-prong plug, the grounding lug or a screw going into the amp’s chassis should be connected to a radiator pipe, or other metal with a path to the building's foundation. Some home-improvement stores sell a blank three-prong plug with only the grounding prong made of metal, and a wire to attach to things that need to be grounded. Every device sensitive to electrical noise, like an analog tape deck or a phonograph, should be attached to the grounding point on the amp or receiver.
A ground loop often occurs in aftermarket car stereo installations, and has the potential to become a nightmare if the installer is not skilled in dealing with the situation. (It can also be exacerbated by spark plug or other engine electrical noise.) It can also occur in the home, but not as frequently since there is a common power connection standard in the wall socket. Also, equipment susceptible to ground loop noise, like a turntable, usually have an extra grounding wire to prevent such a thing from happening.