The role of the ground:
1, to protect human safety: electrostatic discharge will produce a large number of charges, the ground can lead the current to the ground, so as to protect the safety of human life.
2, lightning: tall buildings, all kinds of communication systems will be installed to prevent lightning strike grounding system, encountered a thunderstorm, there is a very good protection, can avoid electrical appliances are damaged.
3, to protect the normal work of the machine: a lot of electrical appliances must have electricity to work, especially in the medical field, the role of the ground is to avoid a sudden power outage will not be affected, can still run some small loads of normal potential.