Selection of the hottest electrical device

2022-08-04
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Selection of electrical devices

1. The electrical appliances in the distribution box and switch box must be reliable and intact. It is strictly prohibited to use damaged and unqualified electrical appliances

2. The electrical appliances of the general distribution box shall have the functions of power isolation, normal connection and disconnection of circuits, as well as short circuit, overload and leakage protection. The electrical equipment shall be set in accordance with the following principles:

1) when the main circuit is set with the main leakage protector, the main disconnector, shunt disconnector, the main circuit breaker, shunt circuit breaker or the main fuse and shunt fuse shall also be installed. When the general leakage protector is a leakage circuit breaker with short-circuit, overload and leakage protection functions at the same time, the general circuit breaker or general fuse may not be set

2) when shunt leakage protector is set for each shunt, main disconnector, shunt disconnector, main circuit breaker, shunt circuit breaker or main fuse and shunt fuse shall also be installed. When the leakage protector set in the shunt station is a leakage circuit breaker with short-circuit, overload and leakage protection functions at the same time, the shunt circuit breaker or shunt fuse may not be set

3) the disconnector shall be set at the incoming end of the power supply, and the disconnector with visible breaking point during disconnection shall be adopted, which can disconnect all poles of the power supply at the same time. If the circuit breaker with visible breaking point is adopted, no additional isolating switch can be set

4) the fuse shall be the product with reliable arc extinguishing and breaking function

5) the rated value and action setting of the main switch shall be consistent with the rated value and action setting value of the shunt switch

3. The general distribution box shall be equipped with voltmeter, general ammeter, watt hour meter and other necessary instruments. The installation of special electric energy measuring instruments shall meet the requirements of the local power supply and consumption management department

when installing the current transformer, the secondary circuit must have a connection point with the protection zero line, and it is strictly prohibited to disconnect the circuit

4. The distribution box shall be equipped with main disconnector, shunt disconnector, main circuit breaker, shunt circuit breaker or main fuse and shunt fuse. Its setting and selection shall comply with the requirements of clause 8.2.2 of this specification

5. The switch box must be equipped with isolating switch, circuit breaker or fuse, and leakage protector. When the leakage protector is a leakage circuit breaker with short-circuit, overload and leakage protection functions at the same time, the circuit breaker or fuse may not be installed. The disconnector shall have a visible breaking point during breaking, and calibration is not required; ③ An 8-channel door lock switch is provided to control the isolating appliance that can disconnect all poles of the power supply at the same time, and shall be set at the incoming end of the power supply. When the circuit breaker has visible breaking point, it is not necessary to set another isolating switch

6. The isolating switch in the switch box can only directly control the lighting circuit and the power circuit with a capacity not greater than 3.0kw, but should not be operated frequently. Power circuit with capacity greater than 3.0kw shall be controlled by circuit breaker, and contactor or other starting control device shall be attached when operation is frequent

7. The rated value and action setting value of various switching devices in the switch box shall be compatible with the rated value and characteristics of the control electrical equipment. The specifications of electrical appliances in the general motor switch box can be selected according to Appendix C of this specification

8. The leakage protector shall be installed at the side of the main distribution box and switch box close to the load, and shall not be used to start the operation of electrical equipment

9. The selection of leakage protector in case of tubing rupture shall comply with the provisions of the current national standards General requirements for residual current operated protectors (GB 6829) and requirements for installation and operation of leakage protectors (GB 13955)

10. The rated leakage action current of the leakage protector in the switch box shall not be greater than 30mA, and the rated leakage action time shall not be greater than 0.1s

the leakage protector used in places with wet or corrosive medium field decomposition temperature of 190 ℃ ~210 ℃ shall be splash proof products, and its rated leakage action current shall not be greater than 15mA, and the rated leakage action time shall not be greater than 0.1s

11. The rated leakage action current of the leakage protector in the general distribution box shall be greater than 30mA, and the rated leakage action time shall be greater than 0.1s, but the product of the rated leakage action current and the rated leakage action time shall not be greater than 30mA? s。

12. I hope to give you some help. The number of poles and lines of leakage protector in the main distribution box and switch box must be consistent with the number of phases and lines of load at the load side

13. Leakage protectors in distribution boxes and switch boxes should be non auxiliary power (electromagnetic) products, or auxiliary power (Electronic) products that can be automatically disconnected in case of auxiliary power failure. When selecting auxiliary power type (Electronic) products that cannot be automatically disconnected in case of auxiliary power failure, phase loss protection shall be set at the same time

14. The leakage protector shall be installed and used according to the product manual. For leakage protectors that have been used for a long time or have been used continuously, their characteristics shall be tested month by month, and problems shall be repaired or replaced in time

the correct use and wiring method of leakage protector shall be selected according to figure 8.2.14

15. It is forbidden to use plugs and sockets for movable connection at the power inlet of distribution box and switch box

16. The distribution box and switch box shall have the name, purpose, shunt mark and system wiring diagram

17. The doors of distribution box and switch box shall be equipped with locks and shall be in the charge of a specially assigned person

18. The distribution box and switch box shall be inspected and maintained regularly. The inspection and maintenance personnel must be professional electricians. During inspection and maintenance, insulating shoes and gloves must be worn as required, electrical insulating tools must be used, and inspection and maintenance records shall be made

19. During the regular maintenance and inspection of the distribution box and switch box, the corresponding power isolating switch at the previous level must be switched off and powered off, and the signboard of no switching on and no working power off shall be hung, and live work is strictly prohibited

20. The distribution box and switch box must be operated in the following order:

1) the power transmission operation sequence is: main distribution box, distribution box and switch box

2) power failure operation sequence: switch box distribution box general distribution box

except in case of electrical failure

21. When the construction site stops working for more than 1 hour, the power switch box shall be powered off and locked

22. The operator of the switch box must comply with the provisions of article 3.2.3 of this specification

23. No sundries shall be placed in the distribution box and switch box, and they shall be kept clean

24. Other electric equipment shall not be connected to the distribution box and switch box at will

25. The electrical configuration and wiring in the distribution box and switch box shall not be changed at will

when replacing the fuse melt, it is strictly prohibited to replace it with the melt that does not meet the original specification. Before using the leakage protector every day, the leakage test button shall be started for trial tripping. It is forbidden to continue to use the leakage protector when the trial tripping is abnormal

26. The incoming and outgoing lines of the distribution box and switch box shall not bear external forces, and shall not contact with sharp metal fractures, strong corrosive media and inflammables and explosives

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