The role of grounding for power adapter

The role of grounding is to prevent personal electric shock, damage to equipment and lines, prevent fire and lightning strikes, prevent electrostatic damage, and ensure the normal operation of power systems.

Grounding is one of electrical safety measures to ensure the normal operation of electrical equipment and personal safety. It is achieved by connecting metal wires to the grounding device. There are are protective grounding, working grounding, lightning protection grounding, shielding grounding, and antistatic groundingto be used commonly. The grounding device introduces the leakage current, static charge and lightning current that may be generated on electrical equipment and other production equipment into the ground, to avoid personal shock and possibility fire and explosion accidents.

1) Prevent personal electric shock
Make a good metal connection between the metal part of the electrical equipment under normal circumstances and the ground electrode to protect the safety of the human body.
For electrical equipment with a grounding device, when the insulation is damaged and the casing is charged, the grounding current will flow through both the grounding electrode and the human body. The value of the current flowing through each path will be inversely proportional to the size of its resistance. The lower the resistance of the ground electrode, the smaller the current flowing through the body. When the grounding resistance is extremely small, the current flowing through the human body approaches zero, to avoids the risk of electric shock on the human body. Therefore, in any case, it should be ensured that the grounding resistance is not greater than the grounding resistance value specified in the design or regulations.

2) Ensure the normal operation of the electrical system
The power system grounding is generally a neutral point grounding, the potential between the neutral point and the ground is close to zero. When the phase line hits the shell or is grounded, the other two relative ground voltages will increase to twice the phase voltage in the neutral point insulation system; in the neutral point grounded system, it will be close to the phase voltage. Thanks to the neutral grounding wire, the reliability of the relay protection can be guaranteed. The DC power supply in the communication system generally adopts the positive electrode ground, which can prevent the noise from entering and ensure the normal operation of the communication equipment.