Distribution box is an indispensable power distribution equipment in modern homes and enterprises, and its installation and use are crucial to the safety and stability of the power system. But when it comes to the taboos of the installation of the distribution box, presumably most electrical personnel are half-understood, and a variety of building electrical lighting distribution box installation work is facing new challenges, therefore, the installation of the lighting distribution box is prone to a variety of problems. Therefore, when installing the lighting distribution box, we need to understand what problems are prone to occur and what taboos need to be observed, so as to ensure the safety of the use of electrical equipment. To ensure safety and reliability, the following article will give you a detailed introduction, after reading the article, I hope to bring you some help in the work.

01 The lighting distribution box (board) is not checked

Consequences: The lighting distribution box (board) is not inspected on the approach, and it is often found after installation: The second layer board has no special grounding bolt, the protection ground wire section is small, the open door equipped with electrical appliances is not reliably connected with the bare copper flexible wire and the metal frame, the wire and the appliance are not firmly connected, there is a reverse ring phenomenon, the screw does not use galvanized parts, the wire diameter does not meet the requirements, the color code is not marked, there is no card cabinet and electrical circuit diagram, the appliance layout and spacing are unreasonable, The N and PE terminals are not configured. The quality is also affected by the delay in the construction period.

Measures: First of all, in the processing of orders should be put forward to the manufacturer in line with the design and specification standards of the technical requirements, ask the manufacturer to make samples, after receiving qualified experience, reproduction; And when the product enters the market, it is inspected and accepted strictly according to the design and standard requirements, and then installed after it is confirmed.

02 The lighting distribution box (panel) is made of wood without flame retardant treatment

Consequences: If the lighting distribution box (board) is used in wet and dusty places, it is easy to mold and leak electricity; In addition, the wooden box (board) is not flame retardant treatment, easy to cause fire, is an unsafe hidden danger.

Measures: In order to ensure safe use, the lighting distribution box (board) should not be made of combustible materials. Even in places without dryness and dust, the wooden distribution box (board) should also be used after flame retardant treatment.

03 Elevation does not meet the requirements, the edge around the panel is not close to the wall

Consequences: The elevation of the lighting distribution box (board) installation does not meet the requirements, the installation is not firm, the box is not vertical, when installing, the edge around the panel is not close to the wall, affecting the use of the function, the look and feel is not good.

Measures: The elevation should meet the design requirements. If the design does not specify, the height between the bottom side of the lighting distribution box and the ground should be 1.5m. The height between the bottom edge of the lighting power distribution board and the ground should be 1.8m. The lighting distribution box (board) should be firmly installed, the allowable deviation of the installation verticality should not be greater than 3mm, when installing, there should be no gap around the distribution box, the edge of the panel should be close to the wall, and the contact part of the box and the building and structure should be coated with anti-corrosion paint.

04 The cables in the lighting distribution box (panel) are cluttered and not bundled

Consequences: The wiring in the lighting distribution box (board) is messy, and the pipe mouth of the two layer board in the box is tightly pressed, which affects the wire into the box. If it is forced into the box, the insulation damage of the wire will be caused for a long time, and it is easy to cause short circuit. And make maintenance inconvenience, affect the perception.

Measures: When metal boxes are used in lighting distribution boxes, anti-rust and anti-corrosion treatment should be done. Do not use electric gas welding to open the cable holes in the box. One pipe must have one hole, and the metal box holes must be properly protected before threading. The cables should be arranged neatly, and the pipes into the box should be placed in a reasonable position. Do not allow the two-layer panels to compress the pipes. The cables in the box should be coiled straight around the box, and bundled neatly.

05 The N and PE bus bars are not installed in the lighting distribution box (panel)

Consequences: The N and PE bus bars are not set in the lighting distribution box (board), and the safe operation of the line cannot be guaranteed.

Measure: The lighting distribution box (board) should be equipped with neutral (N) and PGND (PE) bus bars. The neutral line and PGND cable should be connected on the bus bars, without stranded connections, and should be numbered.

06 The screw fuse installed in the lighting distribution box (board) is not connected correctly

Consequences: The screw fuse wiring installed in the lighting distribution box (board) is not correct, and the power cord is connected to the threaded terminal, which affects the replacement of the melt core, and the improper operation is easy to cause electric shock accidents.

Measures: In order to ensure safety, the screw fuse installed in the lighting distribution box (board) should be connected to the terminal of the middle contact, and the load line should be connected to the terminal of the thread.

07 The protection wire cannot be located, and the wire diameter does not meet

Consequences: The protection wire of the lighting distribution box (board) is not arranged from the terminal, but is connected in series by the box frame, the wire diameter is not set according to the requirements, and the PGND wire is not set for the devices with ultra-safe voltage in the distribution box door, which is easy to cause safety accidents.

Measure: According to the specifications, a PGND cable bus bar should be installed in the lighting distribution box (board), and the PGND cable should be connected to the bus bar. The cross-sectional area of the PGND cable should not be less than the cross-sectional area of the largest lead from the power supply to the electrical appliance. It should also be selected according to relevant regulations. The grounding on the distribution box (board) should be firm and good, and there must be an anti-loosening device.

For open doors with electrical equipment exceeding 50V, the movable panel shall be securely connected to a well-grounded metal frame with a bare copper cord. The cross-sectional area of the bare copper cord should also be selected according to the regulations. The metal box and box body with a wall thickness of less than 2.5mm should not be used as the span of the pipeline. Ground cable and PGND voltage contact of electric appliance. Cross-sectional area of the PGND cable Cross-sectional area of the PGND cable (mm2) Cross-sectional area of the phase conductor S Cross-sectional area SP of the corresponding protection conductor

S≦16 SP=S

16≦S≦35 SP=16

S > 35 SP =S/2

08 The brake inside the lighting distribution box (panel) is not marked with the circuit name

Consequences: The brake in the lighting distribution box (board) does not mark the circuit name, which brings inconvenience to the use and maintenance. If the brake should not be closed by mistake, it is easy to cause safety accidents.

Measures: In general, according to the requirements of the standard, the lighting distribution box (board) door should be affixed with the line system diagram, and the circuit name should be marked on the gate, especially if the lighting distribution box (board) has AC, DC or different levels of power supply, it should have obvious signs. Bring convenience and safety to the work of users and maintenance personnel.

09 Electric appliance instrument installation is not firm, spacing does not meet the requirements

Consequences: The electrical appliances and instruments in the lighting distribution box (board) are not securely installed, uneven, and the spacing is not enough, which affects the safety of use.

Measures: The lighting distribution box (board) power-on devices and meters should be firmly installed, smooth and neat, the spacing should be uniform, the copper terminal is not loose, the opening and closing is flexible, and the parts are complete. The spacing between electric appliances and instruments should meet the requirements in Table 3-19.

10 The wires in the lighting distribution box (board) are not routed according to the color code

Consequences: If not according to the color code wire, in the use of single-phase circuit, because it is not easy to identify the three-phase power supply, it is difficult to balance the load, resulting in serious three-phase imbalance, and in the use of three-phase equipment, because there is no color code, it is easy to mix the phase sequence when wiring, in some equipment operation needs to be fixed steering, and it is not good to grasp the direction of its rotation.

Measures: In order to ensure safety and convenient construction, the wires in the lighting distribution box (board) can be separated into the main line of the tube according to the regulations, but a section of the main line circuit from the pipe port to the main switch of the distribution box (board) and each electrical branch should be separated according to the color standard requirements. In this way, when using single-phase circuit, it can better balance its load, and when using three-phase power supply, it is connected in phase sequence to ensure the normal operation of the equipment.

11 Removable metal plate that is not connected to the PGND cable system

Consequences: The detachable metal plate in the lighting distribution box is equipped with a variety of electrical accessories, and is not connected with the protection ground wire, which is easy to cause electric shock.

Measures: The detachable metal plate in the lighting distribution box should have reliable grounding protection. Therefore, the metal plate should be provided with a special non-detachable ground screw, and the PGND cable should be effectively connected to it. The diameter of the PGND cable should be configured according to the specifications and standards to ensure safe use.

12 The lighting distribution box is improperly located in the shaft

Consequences: The lighting distribution box is located in the shaft, because there are generally strong and weak electricity in the shaft, and the space is very small, not easy to operate, a little careless, easy to cause safety accidents.

Measures: After receiving the drawings, the drawings should be carefully reviewed. If it is found that the layout of the electrical pipes and boxes in the shaft cannot meet the requirements of the specifications and standards, it should be proposed at the time of design disclosure.

Generally, an operation and maintenance distance of not less than o. 8m should be left in front of the lighting distribution box and terminal box in the electrical shaft. In order to prevent the interference of strong current to weak current, strong current and weak current are arranged on both sides of the shaft or isolation measures are taken.

13 The cable and pipe ports in the floor-to-ceiling distribution box are too low

Consequences: The wire and pipeline mouth laid in the floor-to-ceiling distribution box is too low, which is easy to make water and debris enter the pipe and reduce the insulation strength of the wire.

Measures: The cable protection tube in the floor type distribution box should be 50 to 80mm higher than the base surface of the distribution box. The pipes should be arranged neatly, and the pipe mouth should be flared.

14 Metal accessories are not treated with corrosion protection

Consequences: Metal accessories are not galvanized parts or do not do anti-corrosion treatment, easy to corrosion, shorten the service life.

Measures: In order to ensure project quality and extend service life, metal accessories used in wiring and electrical device lighting projects, such as pipe clamp, bracket, hook, pull ring and box (box) bolts, nuts and other black metal accessories, should be galvanized or coated with anti-corrosion paint.