Electrical equipment shell grounding belongs to

Electrical equipment shell grounding belongs to the protective grounding. Under normal circumstances, the metal casing of electrical equipment and the charged part is insulated, the shell will not be charged, but if the internal insulator of the appliance is aging or damaged, electricity may be transmitted to the metal casing up, if the casing is not grounded, then the person if touched on the electrocution, if the metal casing is grounded, the current will flow into the earth through the ground wire, the person touched on the metal casing will not be electrocuted, which belongs to the type of protective grounding. This is a type of protective earthing. Protective grounding, is to prevent the metal casing of electrical devices, power distribution equipment, frames and line towers and other electrically charged and endanger the safety of people and equipment grounding. The so-called protective grounding is not charged under normal circumstances, but in the insulating material is damaged or other circumstances may be charged electrical metal parts (i.e., with the charged part of the metal structure insulated part) with a wire and the grounding body is reliably connected to a protective wiring method. Grounding protection is generally used for distribution transformer neutral point is not directly grounded (three-phase three-wire system) of the power supply system to ensure that when the electrical equipment due to insulation damage and leakage of the ground voltage does not exceed the safety range.