Whether electrical equipment should be connected to zero or grounding
Whether electrical equipment should be connected to zero or with protective grounding depends mainly on whether the neutral point of the power distribution system is grounded, the nature of the low-voltage power grid, and the tentative voltage level of the electrical equipment.
In low-voltage power distribution systems with good grounding at the neutral point, the protection zero connection method should be used. Most factories and enterprises are powered by separate distribution transformers, so they belong to this category. However, except for the following cases: urban public power grids (ie, low-voltage networks supplied by the same distribution transformer to provide more users with electricity) should adopt a unified protection method; all rural distribution networks are due to inconvenience and strict management. To avoid accidents caused by mixing the two protection methods of zero connection and grounding, it is stipulated that the protection of zero connection shall not be implemented, but the protection grounding method shall be adopted.
In low-voltage distribution networks where the neutral point is not grounded, protective grounding is used. High-voltage electrical equipment generally implements protective grounding.