Knkong Electric Co.,Ltd

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What is the grounding and zero connection protection system


1) The TN-S zero-protection system shall be adopted for the low-voltage power distribution system where the neutral point of the power supply dedicated to the construction site is directly grounded;
2) The distribution system on the construction site must not use two protection systems at the same time; 
3) The protective neutral wire should be led out from the working ground wire, the zero wire of the power supply side of the main distribution box or the zero wire of the power supply of the main leakage protector. The metal shell of the electrical equipment must be connected to the protective zero wire;
4) The protective neutral wire should be laid separately. It is strictly prohibited to install switches or fuses on the line, and it is strictly prohibited to pass the working current;
5) The insulated zero wire should be insulated wire, and the specifications and color marking should meet the requirements of the specification; 
6) The protection neutral of the TN system should be repeatedly grounded at the main distribution box, the middle and the end of the distribution system; 
7) The grounding wire of the grounding device should use 2 or more conductors, and make electrical connection with the grounding body at different points. The grounding body should be angle steel, steel pipe or smooth round steel;
8) The working grounding resistance shall not be greater than 4Ω, and the repeated grounding resistance shall not be greater than 10Ω;
9) Cranes, material hoists, construction elevators and scaffolds on the construction site shall take lightning protection measures according to the specifications, and the impact grounding resistance value of the lightning protection device shall not be greater than 30Ω;
10) For the electrical equipment on the lightning protection grounding machine, the protective neutral must be grounded at the same time.

Date:2020-01-08 09:20

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