If ground and earth potential are not properly isolated, the following problems as well as others can occur:
Therefore, earth potential and the negative pole of the power supply of all devices in the electric assembly that provide the option, should be connected separately. If possible, the negative pole of the power supply should only be connected to earth potential at one point in the entire system.
Wiring Example
|
|
|
Device with shielded wires |
Device featuring protection class II |
Occurrence of ground loops The devices shown in the following image do not feature the possibility to connect the earth potential and the negative pole of the power supply separated from each other. How ground loops are created. A ground loop is a ground connection of an electric wiring assembly that is closed as a loop. Due to impedance (resistance R > 0) of the loop, low-frequency interference currents can lead to an unwanted voltage drop in the signal path.
|