1. Work grounding. In order to meet the operational requirements of the power system or electrical equipment, grounding a certain point of the power system is called work grounding, such as neutral grounding of the power system.
2. Lightning protection grounding. In order to avoid damage to the person or equipment caused by lightning overvoltage, the grounding of the overvoltage maintenance equipment is called lightning protection grounding, such as grounding of lightning rod and arrester.
3. Maintain grounding. In order to avoid the insulation damage of electrical equipment, limit the voltage of the metal casing to the ground to a safe voltage, avoid forming a personal electric shock, and ground the metal casing of the electrical equipment through the grounding wire, which is called maintenance grounding, such as:
(1) Metal bases and casings for motors, transformers, lighting appliances, hand-held or mobile electrical appliances and other electrical appliances;
(2) Transmission equipment for electrical equipment;
(3) The structure of the disk (table, box) for power distribution, handling and maintenance;
(4) The structure of the AC/DC power cable, the metal casing of the junction box and the terminal box, the metal sheath of the cable and the threaded steel pipe;
(5) Metal frame of indoor and outdoor power distribution equipment or steel bars of reinforced concrete frame and metal occlusion and metal doors close to the live parts.
4. Repeat grounding. In the TN-C system of the low-voltage power distribution system, in order to avoid the loss of grounding maintenance due to neutral line faults, the risk of electric shock and damaged equipment are formed, and the neutral line is repeatedly grounded.
5. Anti-static grounding. In order to eliminate the grounding caused by static electricity damage to people and equipment, such as the metal of certain liquids or gases, or the grounding of the vehicle.
6. Shield grounding. In order to avoid electrical equipment from being disturbed by electromagnetic interference, the grounding of shielding equipment that affects its operation or forms electromagnetic disturbance to other equipment.