Grounding

Connecting the ground terminal of power equipment to the earth with a conductor. Grounding plays an important role in preventing electric shock by allowing abnormal voltage to escape into the earth when equipment becomes electrically charged due to leakage current or other faults. Therefore, the grounding resistance value, which is the resistance between the ground terminal and the earth, is required to be low in order to allow current to flow easily into the ground. According to the Technical Standards for Electrical Installations, for low-voltage equipment of 300V or less, the grounding resistance must be 100Ω or less (Class D grounding). In addition to preventing electric shock, grounding may also be implemented as a countermeasure against noise.

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