Summary of construction and installation points of distribution box and switch box

1. Distribution box and switch box settings

(1) The power distribution system should be equipped with a general distribution box and a distribution box to implement graded power distribution.

(2) The switch box should be distributed by the last stage distribution box.

(3) The horizontal distance between the switch box and the controlled fixed electrical equipment should not exceed 3M.

(4) There should be enough space and passage for two people to work at the same time around the distribution box and switch box, and no items that hinder operation and maintenance should be stacked.

(5) The distribution box and switch box should be installed correctly and firmly, and the mobile distribution box and switch box should be installed on a solid bracket. The bottom of the fixed distribution box and switch box is greater than 1.3M and less than 1.5M.

(6) Switches and sockets in the distribution box should be firm, not loose or skewed.

(7) The working neutral wire and the protective ground wire in the distribution box and switch box shall not be mixed.

(8) The connecting wires in the distribution box and switch box should be insulated wires, the joints should not be loose, and there should be no exposed live parts.

(9) The metal box of the distribution box and switch box, the installation of metal electrical appliances, and the uncharged metal base and shell of the electrical appliances in the box must be grounded for protection. The protective neutral line should be connected through the terminal block.

(10) The distribution box and switch box must be rain-proof, dust-proof and smash-proof.

2. Selection of electrical installations

(1) The electrical appliances in the distribution box and switch box must be reliable and intact, and damaged or substandard electrical appliances are not allowed.

(2) The main distribution box should be equipped with main automatic switch and branch automatic switch, main fuse and branch fuse, and leakage protector. The rated value and action setting value of the main switch should be compatible with the shunt switch.

(3) The main distribution box should be equipped with a voltmeter, a total ammeter, a total watt-hour meter and other instruments.

(4) The main automatic switch and branch automatic switch, the main fuse and the branch fuse shall be installed in the distribution box. The rated value and action setting value of the main switch should be compatible with the shunt switch.

(5) Each electrical equipment should have its own dedicated switch box, and the system of "one machine, one gate" must be implemented, and it is strictly forbidden to use the same switch to directly control two or more electrical equipment.

(6) The switching appliances in the switch box must be able to use electrical equipment to implement power isolation under any circumstances.

(7) A leakage protector must be installed in the switch box. The leakage protector shall be installed on the load side of the power isolating switch of the distribution box and the load side of the power isolating switch of the switch box.

(8) The selection of the leakage protector should meet the requirements of the national standard GB6829-86 "Leakage Current Action Protector (Residual Current Action Protector)". The rated leakage current of the leakage protector in the switch box should not exceed 30mA, and the rated leakage current The action time should be less than 0.1S.

(9) The rated leakage current and rated leakage operation time of the two-level leakage protectors in the main distribution box and switch box should be reasonably matched to make them have the function of graded and segmented protection.

(10) The leakage protector must be installed and used according to the product manual. For the leakage protector that has been put on hold for a long time and has been used continuously for one month, its characteristics should be carefully checked, and any problems should be repaired or replaced in time.

(11) Manual switch electrical appliances can only be used to directly control lighting circuits and power circuits with a capacity not greater than 5.5KW. Power circuits with a capacity greater than 5.5KW should be controlled by automatic switching appliances or step-down starting devices.

(12) The ratings of various switching appliances should be compatible with the ratings of the electrical equipment they control.

(13) The inlet and outlet of the wires in the distribution box and switch box should be located on the bottom surface of the box, and it is strictly forbidden to set them on the top, side, back or door of the box. The incoming and outgoing wires should be bundled with sheaths and shunt and waterproofed, and the wire bundles should not be in direct contact with the inlet and outlet of the box. The inlet and outlet lines of the mobile distribution box and switch box must use rubber insulated cables.

(14) The power cord entering the switch box must not be connected to a socket.

3. use and maintenance

(1) All distribution boxes should be marked with their names, uses, and shunt marks.

(2) All distribution box doors should be equipped with locks, and special personnel should be responsible for distribution boxes and switch boxes.

(3) All distribution boxes and switch boxes should be inspected and maintained once a month. Inspection and maintenance personnel must be professional electricians. During inspection and maintenance, insulating shoes and gloves must be worn as required, and electrical insulating tools must be used.

(4) When inspecting and maintaining the distribution box and switch box, the corresponding power switch of the previous stage must be turned off and power off, and the power failure sign shall be hung, and live work is strictly prohibited.

(5) All distribution boxes and switch boxes must follow the following sequence of operations during use:

Operation sequence of power transmission: general distribution box - distribution box - switch box

Power failure operation sequence: switch box - distribution box - main distribution box

Except for emergency measures in case of electrical failure.

(6) When the construction site stops working for more than one hour, the power switch box should be powered off and locked.