14 installation taboos for lighting distribution boxes compiled by an old electrician

14 installation taboos for lighting distribution boxes

Taboo 1

The lighting distribution box (board) has not been inspected upon arrival

Consequence: The lighting distribution box (board) has not been inspected upon arrival, and it is often discovered after installation that the second floor board does not have a dedicated grounding bolt, the cross-section of the protective ground wire is small, the openable door containing electrical appliances is not reliably connected to the metal frame with bare copper flexible wires, the connection between the wires and appliances is not firm, and there are reverse turns. The screw nut does not use galvanized parts, and the wire diameter does not meet the requirements. It is not marked according to the color code, and there is no card cabinet or electrical circuit diagram, The layout and spacing of the equipment are unreasonable, and there are no N and PE terminal blocks set up.

Measures: When processing and ordering, technical requirements that meet the design and specification standards should be proposed to the manufacturer. The manufacturer should make samples and pass the acceptance before production; When the product enters the site, it shall be strictly inspected and accepted in accordance with the design and standard requirements, and installation shall be carried out after confirmation of conformity.

Taboo 2

Using wood materials without flame retardant treatment

Consequence: If the lighting distribution box (board) is used in a damp and dusty place, the wooden one is prone to mold and leakage. In addition, wooden boxes (boards) without flame retardant treatment are prone to fire and are an unsafe hazard.

Measures: To ensure safe use, it is required that the lighting distribution box (board) should not be made of combustible materials. Even in dry and dust-free places, wooden distribution boxes (boards) used should be treated with flame retardancy before use.

Taboo 3

Unsecure installation

The elevation does not meet the requirements

During concealed installation

The edges around the panel are not tightly attached to the wall surface

Consequence: The installation elevation of the lighting distribution box (board) does not comply with the regulations, the installation is not firm, the box is not vertical, and when concealed, the edges around the panel do not closely adhere to the wall, affecting the use function, and the appearance is not good.

Measures: The elevation should meet the design requirements, and the bottom edge of the lighting distribution board should be 1.8m above the ground. The installation of lighting distribution boxes (boards) should be firm, and the allowable deviation in installation perpendicularity should not exceed 3mm. When concealed, there should be no gaps around the distribution box, and the edges of the panel should be close to the wall. The contact area between the box and the building or structure should be coated with anti-corrosion paint.

Taboos 4

The lines intersect in disorder and are not bundled together

Consequence: The wiring inside the lighting distribution box (board) is messy, and the second layer of the board inside the box is tightly pressed against the pipe opening, which affects the entry of wires into the box. If the wires are forced into the box, the insulation of the wires will be damaged over time, which can easily cause short circuits. And it makes maintenance inconvenient and affects the appearance.

Measures: When using metal boxes for lighting distribution boxes, rust prevention and anti-corrosion treatment should be carried out. The outlet holes in the box cannot be opened by electrical welding. Each pipe should have one hole, and the metal box holes should be protected before threading. The wiring should be arranged neatly, and the position of the pipes entering the box should be reasonably arranged. The second layer board should not be tightly pressed on the pipes. The wires inside the box should be coiled straight around the box and bundled neatly.

Taboos 5

Do not set N and PE busbars

Consequence: N and PE busbars are not installed in the lighting distribution box (board), which cannot ensure the safe operation of the line.

Measures: In the lighting distribution box (board), a neutral line (N line) and a protective ground wire (PE line) busbar should be installed separately. The neutral line and protective ground wire should be connected on the busbar, not twisted, and should be numbered.

Taboos 6

Incorrect wiring of the installed spiral fuse

Consequence: The spiral fuse installed in the lighting distribution box (board) is not wired correctly. Connecting the power cord to the threaded terminal can affect the replacement of the fuse core, and improper operation can also lead to electric shock accidents.

Measures: To ensure safety, the power line of the spiral fuse installed in the lighting distribution box (board) should be connected to the terminal of the intermediate contact, and the load line should be connected to the threaded terminal.

Taboos 7

The protective wire is not done properly

Wire diameter does not match

Consequence: The protective wires of the lighting distribution box (board) are not arranged from the terminals, but are connected in series using the box structure. The wire diameter is not set according to the requirements, and the protective ground wire is not set for devices with ultra safe voltage on the distribution box door, which can easily cause safety accidents.

Measures: According to regulatory requirements, a protective ground wire busbar should be installed inside the lighting distribution box (board), and the protective ground wire should be connected to the busbar. The cross-sectional area of the protective ground wire should not be less than the cross-sectional area of the maximum lead wire from the power supply to the corresponding electrical appliance, and should also be selected according to relevant regulations. The grounding on the distribution box (board) should be firm and good, and there must be anti loosening devices.

Taboos 8

The circuit name is not indicated on the brake

Consequence: The switches inside the lighting distribution box (board) are not labeled with circuit names, which brings inconvenience to use and maintenance. If the wrong switch is accidentally closed, it can easily cause safety accidents.

Measures: Generally, according to the requirements of regulations and standards, the lighting distribution box (board) should have a circuit system diagram posted inside the door, and the circuit name should be indicated on the gate. Especially, if there are AC, DC or different levels of power supply inside the lighting distribution box (board), there should be obvious signs to facilitate the work of users and maintenance personnel.

Taboos 9

The installation of electrical appliances and instruments is not firm or flat

The spacing does not meet the requirements

Consequence: The installation of electrical appliances and instruments in the lighting distribution box (board) is not firm, flat, and the spacing is not enough, which will affect the safety of use.

Measures: The electrical appliances and instruments on the lighting distribution box (board) should be installed firmly, smoothly, and neatly, with even spacing, no loose copper terminals, flexible opening and closing, and complete components.

Taboos 10

Wire not threaded according to color code

Consequence: If the wires are not threaded according to the color code, it is difficult to balance the load when using single-phase circuits due to the difficulty in identifying the three-phase power supply, resulting in serious three-phase imbalance. However, when using three-phase equipment, without the color code, it is easy to mix the phase sequence during wiring, and it is difficult to grasp the direction of rotation when some equipment requires fixed turning during operation.

Measures: In order to ensure safety and construction convenience, the wires inside the lighting distribution box (board) can be threaded into the main line of the pipe according to regulations without color separation. However, the main circuit and each power branch from the pipe mouth to the main switch of the distribution box (board) should be colored according to the color code requirements. This way, when using a single-phase circuit, it can better balance its load. When using a three-phase power supply, it should be connected in phase sequence to ensure the normal operation of the equipment.

Taboos 11

Detachable metal plate

Not connected to the protective ground wire system

Consequence: The detachable metal plate inside the lighting distribution box is equipped with various electrical accessories, without a protective ground wire, which can easily lead to electric shock accidents.

Measures: The detachable metal plate in the lighting distribution box should have reliable grounding protection. Therefore, it is required that there should be a non detachable special grounding screw on the metal plate, and the protective ground wire should be effectively connected to it. The diameter of the protective ground wire should be matched according to the requirements of the specifications and standards to ensure safe use.

Taboos 12

Inappropriate location within the shaft

Consequence: The lighting distribution box is located inside the vertical shaft. Due to the generally strong and weak electricity in the shaft, and the space is very small, it is not easy to operate. If there is a slight carelessness, it can easily cause safety accidents.

Measures: After receiving the drawings, the drawings should be carefully reviewed. If it is found that the layout of various electrical pipelines and boxes in the vertical shaft cannot meet the requirements of the specifications and standards, it should be proposed during the design disclosure. It is generally required to leave a distance of no less than 0.8m for operation and maintenance in front of the lighting distribution box and terminal box in the electrical shaft. To prevent interference from strong electricity on weak electricity, strong and weak electricity should be arranged separately on both sides of the shaft or isolation measures should be taken.

Taboos 13

Wire conduits in floor mounted distribution boxes

Laying too low

Consequence: The opening of the wire pipeline laid in the floor mounted distribution box is too low, which can easily cause water and debris to enter the pipe, reducing the insulation strength of the wire.

Measures: The wire protection pipe in the floor mounted distribution box should have its mouth 50 to 80mm higher than the basic surface of the distribution box. The pipeline should be arranged neatly, and the pipe orifice should be in a trumpet shape.

Taboos 14

In wiring and electrical installation lighting engineering

All metal accessories

Not galvanized parts and not subjected to anti-corrosion treatment

Consequence: Metal accessories are not galvanized or do not undergo anti-corrosion treatment, which is highly corrosive and shortens their service life.

Measures: In order to ensure the quality of the project and extend its service life, it is required that all metal accessories used in wiring and electrical installation lighting projects, such as pipe clamps, brackets, hooks, pull rings, and black metal accessories such as box (box) bolts and nuts, should be galvanized or coated with anti-corrosion paint.