The distribution box is assembled according to the requirements of electrical wiring. The switchgear, measuring instrument, protective appliance and auxiliary equipment are assembled in a closed or semi-closed metal box or on the screen, which is a low-voltage distribution box. The circuit can be switched on and off by manual or automatic switching during normal operation. In the event of a fault or malfunction, the circuit is switched off or alarmed by means of a protective device. The measuring instrument can display various parameters in the operation of the circuit, and can also adjust some parameters to prompt or signal the deviation from the normal working state. Commonly used in factories, buildings, and substations.
1. Classification and general provisions of the distribution box The distribution box mainly has three installation methods: hanging type, in-wall type and floor type. The installation should meet the basic requirements of the distribution box.
(1) The distribution box can be divided into indoor and outdoor. The indoor distribution box is suitable for offices and production sites, and the outdoor distribution box is suitable for transformers, lighthouses, light bridges and other premises.
(2) Both the indoor distribution box and the outdoor distribution box should be made of iron distribution box. The iron distribution box should be made of 2mm thick iron plate. When the length of the distribution box is 600mm or more, double door should be used. . The indoor distribution box can be installed in both dark and clear modes.
(3) The cabinet of the iron distribution box should be treated with anti-corrosion treatment before installation. Apply a primer first and then apply two gray paints.
(4) There should be a grounding terminal in the iron distribution box. The distribution box door should be opened outwards. The box door should be locked. The outdoor distribution box should be well sealed and protected from dust and rain.
2. Production and related regulations of distribution box
(1) The indoor and outdoor distribution boxes should be equipped with a main switch in front of the meter. Generally, no more than 4 circuits are allocated after the meter. Each circuit should be equipped with a sub-switch. When there is only one circuit, the table may not be Set the switch.
(2) When the load current exceeds 15A, the current transformer should be installed. The accuracy level of the current transformer is 0.5 or above. The current transformer should be installed behind the switchboard.
(3) Current transformers, main switches, electric energy meters, and sub-switches of each circuit can be installed in a floor-standing distribution box and the installation of high and low voltage switchgear is basically similar. According to the drawings, a power distribution box shall be installed. The electricity meter shall be installed separately for the load of different electricity prices. As a base or pre-embed mechanical bolts, and then assembled, the specific installation steps are as follows.
1) The switch, electric energy meter, fuse and other equipment on the switchboard should be installed vertically, the upper end is connected to the load, and the phase sequence is the same, from left to right, A, B, C, or AN, BN, CN, respectively The circuit shall indicate the name of the circuit, a system diagram, and the name of the inspector.
2) The distribution box under the change table should be made open on both sides (doors open outwards). For easy maintenance, the distribution box should be installed on the bracket. The height of the bottom of the distribution box should not be less than 1.2m from the bottom. connection. The introduction (outlet) of the distribution box shall be piped, and the protection pipes shall be arranged neatly and blackened with oil, and the cable shall be marked on the protection pipe.
3) All electrical appliances on the switchboard should be neatly arranged, and the minimum clear distance between the components should not be less than the specified value.
4) Production and processing of the main distribution box. The total distribution box is equipped with a total isolating switch, a shunt disconnecting switch, a total electric energy meter, and a shunt leakage circuit breaker, and is provided with a working neutral terminal block, a protective neutral terminal block, and a three-phase five-wire terminal block.
5) Distribute the electrical box for processing. The distribution box is equipped with a total isolating switch, a shunt leakage circuit breaker, and a working neutral terminal block, a protective neutral terminal block, and a three-phase five-wire terminal block.
6) Switch box production and processing. The switch box is provided with a total fuse, a total isolating switch, a shunt fuse, a shunt breaker, a three-phase four-wire socket and a single-phase three-wire socket, and a working neutral terminal block and a protection neutral terminal block.
3. Wiring and installation of distribution box
(1) The selected conductor cross section should meet the requirements of equipment capacity and safe current carrying capacity. The copper conductor should not be less than 1~5mm; the aluminum conductor should not be less than 2.5ram2. The conductor below 10mm~ should be used in single strand and twice in the box. There should be no connectors on the line.
(2) The wiring of the distribution box generally adopts the wiring behind the board. The lead wire should be insulated from the panel. The loops should be neatly arranged and the wiring should be beautiful. When the ends of the wires are separated, the cores, wires and equipment should not be damaged. Wiring terminals are generally used for connection, and bus wiring is preferred. Do not wire the wires themselves.
(3) When the wire is passed through the pipe, the total section of the wire shall not exceed 40% of the inner diameter of the protection pipe. There shall be no joints in the pipe. The wire shall not be damaged when threading, and the wires of different circuits are not allowed to penetrate into the same protection pipe.
(4) The protective tube enters the box body, and the end should be provided with a protective wire hoop. The protective tube is not allowed to have a joint. When the cable is introduced (out), the inner diameter of the protective tube should be greater than 1.5 times the outer diameter of the cable.
(5) The indoor distribution box should be installed in a place that is dry, bright, not easily damaged and vibrated, and is convenient for operation and maintenance. It should not be installed in a damp place and as close as possible to the load center. Do not install in the pool or water gate. The fixing bolts should not be less than M10mm.
(6) The installation height of the distribution box shall be determined according to the design requirements. If there is no regulation, the height of the bottom of the wall of the wall mounted or dark assembled electrical box shall not be less than 1.2m; the vertical and horizontal deviation of the installation of the distribution box shall not exceed 3mm. The height of the distribution box installation in the same building should be the same.
(7) When the distribution box embedded in the wall needs to be reserved, the reserved hole size should be about 20mm larger than the outer shape of the distribution box; when it is concealed in the 240mm thick wall, the rear wall of the wall needs to be installed with 10mm. Thick asbestos board with wire mesh and smooth with 1:2 cement mortar to prevent cracking.
(8) The metal components of the distribution box, the iron plate surface and the metal casing of the electrical appliance shall have good grounding.
(9) After the installation of the distribution box, the insulation resistance test shall be carried out. The insulation resistance shall not be less than 0.5MΩ, and the certificate of all electrical appliances shall be retained.
4. Installation of floor-standing distribution box
(1) Pre-bury the channel steel or anchor bolts on the designed cable trench.
(2) Measure the horizontal and verticality of the I-beam.
(3) Hang the distribution box on the I-beam and level it to be fixed.
(4) Make the cable end of the cable in the cable trench and connect it to the equipment in the power distribution box.
(5) Clean the distribution box and check the isolation switch, fuse, operating mechanism, small busbar, instrument, etc.
(6) Decorate the distribution box and repaint if necessary. Indicate the name and number of the appliance in the cabinet.
Suizhou simi intelligent technology development co., LTD , https://www.msmvape.com