The installation position of the low-voltage distribution box should be protected from direct sunlight, avoid splashing water, avoid moisture, and have sufficient operating space in front. The equipment in the cabinet should be cleaned regularly, the terminals should be inspected, the switches should be inspected, the contactors should be good, and there should be no overheating inside. The sealing performance of the power distribution cabinet should be checked regularly to prevent small animals from entering or dew condensation inside. For areas with high humidity, it is also equipped with a humidifier, a dryer, and the like. The installation position should be checked for firmness and must not be shaken.
(1) Equipment requirements
1) The appearance of the cabinet (disc) should be inspected without damage and deformation, and the paint should be intact. Internal inspection of the cabinet (disc): electrical equipment and components, insulating porcelain parts are complete, no damage, cracks and other defects.
2) Before installation, check whether the distribution box number is consistent with the installation position, and check the box number and the circuit number inside the box according to the design drawings. The grounding of the door should be made of soft copper braided wire and special terminal block. The wiring inside the box should be neat and meet the requirements of design requirements and acceptance specifications (GB50303-2002).
(2) Working conditions
The civil works of the installation box of the distribution box shall have the basic conditions for the completion of the internal painting and the installation of the doors and windows. The buried pipeline and the embedded parts should be cleaned up; the site has transportation conditions to keep the road smooth and smooth.
(3) Distribution box positioning: According to the design requirements, determine the location of the distribution box and the actual equipment installation on the site, and locate the elastic line according to the outer dimensions of the box.
(4) Basic steel installation
1) Prefabricated and processed basic steel frame according to the requirements of the drawings, and do anti-corrosion treatment. Place the prefabricated basic steel frame on the reserved iron piece according to the position marked on the construction drawing, leveling and aligning the basic steel. The frame, the embedded iron parts and the gasket are welded and welded firmly. Finally, the top of the basic steel should be 10mm higher than the flat surface.
2) Basic steel grounding: After the basic steel is installed, the grounding wire should be welded to both ends of the basic steel. The welding surface is twice the width of the flat steel, and then connected to the grounding bar of the cabinet. And do anti-corrosion treatment.
(5) Distribution cabinet (disk) installation
1) Cabinet (disc) installation: According to the layout of the construction drawing, the power distribution cabinets should be placed one by one on the basic section steel. The vertical adjustment of the cabinet surface and the side of the cabinet (disk) can be solved by adding the iron, but not more than three pieces, and the welding is firm. After each row of cabinets (discs) is in place, the level and panel deviation of the cabinets should be adjusted and adjusted to meet the construction specifications.
2) The wall-mounted distribution box can be fixed to the wall by expansion bolts, but the hollow brick or block wall should be pre-embedded with dovetail bolts or fixed by pulling bolts.
3) The installation of the distribution box should be pre-embedded, and the rear panel should be level with the wall.
4) After the adjustment of the cabinet (disc), apply the bolts to fasten the cabinet to the basic section steel.
5) Cabinet (disk) grounding: Each cabinet (disk) is connected to the basic steel separately. The copper wire can be reliably connected with the grounding bolt and the spring washer can be used for anti-loose treatment. Each cabinet door should be reliably connected to the PE row by a copper braided wire.
6) The top of the cabinet (disc) is connected with the busbar. Note that the busbar supporting wrench should be used for fastening according to the requirements. The contact surface should be coated with neutral Vaseline. When connecting the busbars between cabinets, please pay attention to whether the busbars are too close to other devices or housings, and pay attention to the correct phase.
7) Control circuit check: It should be checked whether the line is loosened due to transportation and other factors, and tightened one by one, and the electrical components are damaged. In principle, the cabinet (disc) control line is verified at the factory, and the line inside the cabinet should not be adjusted privately. If problems are found, contact the supplier.
8) After the control line is calibrated, each core wire is circled and connected to each terminal plate with galvanized screws, eye circles and spring pads. One terminal on each side of the terminal block is usually pressed by one wire, and the maximum number of wires cannot be more than two, and the eyelets are added between the two wires. Multi-strand lines should be tinned, and no breaks are allowed.
(6) Cabinet (disk) test adjustment
1) The high voltage test shall be carried out by a test unit licensed by the local power supply department. The test standards are in line with national regulations, local power supply department regulations and product technical data requirements.
2) Test content: high voltage cabinet frame, bus bar, lightning arrester, high voltage porcelain bottle, voltage transformer, current transformer, various switches, etc.
3) Adjustment content: overcurrent relay adjustment, time relay, signal relay adjustment and mechanical interlock adjustment.
4) Secondary control small line adjustment and simulation test, tighten all the terminal screws again.
5) Insulation test: Test the resistance of each circuit at the terminal board with a 500V insulation resistance tester. The resistance must be greater than 0.5MΩ.
6) If there are transistors, integrated circuits or electronic components in the secondary small-line circuit, use a multimeter to test whether the circuit is connected.
7) Turn on the temporary control power and operating power; remove the upper phase of the control and operation power circuit fuses in the cabinet (disk) and connect the temporary power supply.
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