Template:Networking device manual powering options ground loops switches
Ground loops
Do not connect the power supply negative terminal of our device to the chassis or earth exclusively.
This connection could cause ground loops. For example, if the antenna shield and power supply negative terminal are connected to the chassis or earth, it forms a ground loop, therefore unwanted current could flow through a device PCB ground and may cause damage.
In networking switches connecting our device power supply negative terminal to the chassis or earth could cause damage to other devices connected to the switch or unintentional power up of other devices.