Grounding
Ground wires are attached to earth and dissipate electricity.
The ground wire should have a voltage of zero unless there is a problem.
Grounding protects against lightning, faulty wiring, and ESD.
Another very important function of grounding is that it serves as a zero voltage reference point for the computer.
The ground inside the computer is called the grounding plate or signal reference ground.
It is part of the computer case or chassis.