1. The power distribution system of the construction site is classified into three levels, and the main distribution board (or distribution room) is set. The switch box is set below the main distribution board, and the power consumption equipment is below the switch box.

2. The main distribution board should be set near the power supply, where the power consumption equipment of the distribution box or the load is concentrated; When the distance between the distribution box and the switch box exceeds 30m, the switch box shall not distribute power in the terminal distribution box. When the horizontal distance between the switch box and the fixed electrical equipment controlled by it exceeds 3M, the switch box shall not be used.

3. The distribution board and switch box of the construction site shall be set in a ventilated, dry and normal temperature place. It is strictly forbidden to install on the gas, smoke, steam, liquid and other harmful media with serious damage, and it is not allowed to install in the place vulnerable to impact, vibration, liquid invasion and heat source burning. A tea space and channel are needed around the distribution board and switch box. Two people work on the cloud synchronously. Do not pile up objects that hinder operation and maintenance, and do not have weeds Shrubs, etc.

4. The distribution board and switch box must be made of iron element board or excellent insulating material, and the thickness of iron element board must be greater than 1.5mm. For the electrical equipment in the distribution board, please install it on the metal or non wood insulation electrical equipment installation board first, and then fasten it in the shell of the distribution board as a whole. Please make electrical connection between metal plate and switchboard shell.

5. The connecting wires in the distribution boards and switch boxes at the construction site are insulated wires, and the joints are not loose, so the live parts are not exposed. The working zero line in the distribution board and switch box shall be connected with the wiring terminal board, and the protective zero line shall be separated from the wiring terminal board. Metal box of distribution board and switch box, metal electrical installation board and non charged metal base of electrical equipment in the box