As an electrical person, must know the 14 taboos of the installation of the distribution box!
Distribution boxes are essential power distribution equipment in modern homes and businesses, and its installation and use is crucial to the safety and stability of the power system.
But when it comes to the taboo of distribution box installation, I think most of the electrical personnel are half-knowledgeable. A variety of building elctrical causes the installation of lighting distribution boxes to face new challenges, so the installation of lighting distribution boxes is prone to a variety of problems.
Therefore, when installing lighting distribution boxes, we need to understand what problems are prone to 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 gives you a detailed introduction, read the article, I hope to bring you some help in the work picture!
01Lighting distribution box (board) into the field did not do the inspection
Consequences: Lighting distribution box (board) into the field without inspection, often found only after installation: its two-layer board without special grounding bolts, small cross-section of protective ground, openable door with electrical appliances is not connected reliably with bare copper soft wire and metal frame, wire and apparatus connection is not solid, anti-loop phenomenon, screw mother does not use galvanized parts, wire diameter does not meet the requirements, not marked by color code, no card cabinet and electrical wiring diagram The layout and spacing of the apparatus are unreasonable, and no N and PE terminal blocks are set. Further modification delays the work schedule also affects the quality.
Measures: First of all, when processing the order, you should propose to the manufacturer to meet the technical requirements of the design and specification standards, ask the manufacturer to make samples, after acceptance, and then production; and when the product is in the field, strictly according to the design and specification standard requirements for inspection and acceptance, confirm qualified before installation.
02Lighting distribution boxes (panels) using wood materials without fire retardant treatment
Consequences: Lighting distribution box (board) if used in humid and dusty places wooden easy mold and leakage; In addition, the wooden box (board) does not go through flame retardant treatment, easy to start a fire, is not a safe hidden danger.
Measures: To ensure safe use, the lighting distribution box (board) should not be made of combustible materials. Even in a dry and dust-free place, the wooden distribution box (board) used should be treated with flame retardant before use.
03 The elevation does not meet the requirements, and the edges around the panel are not close to the wall
Consequences: The elevation of the lighting distribution box (board) installation does not meet the regulations, the installation is not solid, the box is not vertical, and when installed, the edges around its panel do not cling to the wall, affecting the use of function, and the appearance is not good.
Measures: Elevation should meet the design requirements, the design does not specify, the bottom edge of the lighting distribution box from the ground height of 1.5 m. Lighting distribution board bottom edge from the ground height of 1.8 m. Lighting distribution box (board) installation should be solid, installation verticality allowable deviation should not be greater than 3mm, installation, distribution box should be surrounded by no gaps, panel around the edge should be close to the wall, the box and the building, building contact parts coated with Anti-corrosion paint.
04 Lighting distribution box (board) within the line cross messy, not tied into a bundle
Consequences: lighting distribution box (board) within the line mess, the box of the second layer of the board tight pressure tube mouth, affecting the conductor into the box, if forced to squeeze in, over time the wire insulation damage, easy to cause a short circuit. And make maintenance inconvenience, affecting the appearance.
Measures: When using metal boxes for lighting distribution boxes, do rust and corrosion prevention treatment. Box out of the hole can not use electrical welding to open the hole, to a tube a hole, metal box hole to be in the threading before the protective set good. The line should be arranged neatly, the location of the tube into the box should be reasonably laid out, do not let the second layer of the board tight pressure on the tube, the box should be straight wire coiled around the box, and tied into a bundle neatly.
05 Lighting distribution box (board) is not set N and PE sink
Consequence: No N and PE sink is set in the lighting distribution box (board) to ensure safe operation of the line.
Measures: Lighting distribution box (board), should be set up separately zero line (N line) and protection ground (PE line) sink, zero line and protection ground should be connected on the sink, shall not be stranded, and should be numbered.
06 Lighting distribution box (board) installed spiral fuse its wiring incorrectly
Consequences: Lighting distribution box (board) installed spiral fuse wiring incorrectly connected to the power line to the threaded terminals, affecting the replacement of the fuse core, and improper operation, but also easy to cause electric shock accidents.
Measures: To ensure safety, the spiral fuse installed in the lighting distribution box (board), the power line should be connected to the middle contact terminal, the load line should be connected to the threaded terminal.
07 The protection wire is not done properly, the wire diameter does not meet
Consequences: Lighting distribution box (board) protection line is not arranged from the terminal out, but the use of box frame series connection, the wire diameter is not set according to the requirements, distribution box door with ultra-safe voltage devices are not set up to protect the ground, easy to cause safety accidents.
Measures: According to the specification requirements, lighting distribution box (board) within, should be set up to protect the ground sink, the protection ground should be connected on the sink. The cross-sectional area of the protective ground wire should not be less than the cross-sectional area of the largest lead from the power supply to the appliance to which it belongs; and should also be selected in accordance with the relevant provisions. Distribution box (board) on the ground should be solid and good, and must have anti-loose device.
The door with more than 50V electrical equipment can be opened, the active panel should be connected reliably with a well grounded metal frame with bare copper wire. The cross-sectional area of bare copper flexible wire should also be selected according to regulations. And wall thickness of less than 2.5mm metal box, box body should not be used as a pipeline across. Grounding line and electrical apparatus protection ground crimp point. The cross-sectional area of the protective ground wire according to the table protective ground wire cross-sectional area (mm2) the cross-sectional area of the phase conductor of the device S corresponding to the cross-sectional area of the protective conductor SP
S≦16 SP=S
16≦S≦35 SP=16
S＞35 SP =S/2
08Lighting distribution box (board) inside the gate is not marked circuit name
Consequences: Lighting distribution box (board) within the gate is not marked circuit name, to the use and maintenance of inconvenience, if it is wrongly closed should not close the gate, easy to cause safety accidents
Measures: In general, according to the standard requirements, the lighting distribution box (board) door should be posted 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, it should have obvious signs. Bring convenience and safety to the work of the user and maintenance personnel.
