Structural requirements for explosion-proof distribution boxes:
1. The outer surface of the Distribution Box shell is coated with silver-gray powder paint. The explosion-proof joint surface of the explosion-proof distribution box is coated with 204-1 displacement type anti-rust oil.
2. The insulation level of the insulation material in the junction box of the explosion-proof distribution box is not less than 6mm, and the creepage distance is not less than 10mm.
3. The material of the explosion-proof distribution box shell is made of cast aluminum alloy with magnesium content not more than 6% (mass percentage).
4. Explosion-proof power distribution shall be provided with internal and external grounding screws. The size of the internal grounding screw shall not be less than M6, and the size of the external grounding screw shall not be less than M8.
5. The explosion-proof distribution box enclosure should have a clear and permanent relief mark “Ex†in the obvious place. EX is the general mark of explosion protection, the abbreviation of Explosionp-roof in English. With this mark, the product is explosion-proof and can be used in specific hazardous locations.
6. The minimum width L and the maximum gap ic of the explosion-proof distribution box explosion-proof joint surface corresponding to the volume of the casing shall comply with the provisions of Table 3 of Class IIB of GB3836.2-2000, and the Class IIC shall be as specified in Table 4, and the joint surface shall be fastened. The distance between the bolt hole and the inside of the casing l shall comply with the provisions of 5.2.6 of GB3836.2-2000, and the average roughness Ra of the joint surface shall not exceed 6.3 μm.
7. The transparent part of the observation box of the distribution box is directly glued in the opening of the cover, and the shortest path from the inside to the outside of the flameproof casing through the adhesive bonding surface is not less than 10mm.
8. All ferrous metal parts of the explosion-proof distribution box must have anti-rust measures, and the surface must not be peeled off.
9. The operating handle of the explosion-proof distribution box must be flexible and reliable, and should have a clear "divided" and "closed" mark.
10. The distribution box should be provided with nameplates and warning signs. Nameplates and warning signs are made of brass plates or other chemically resistant materials.
11. If you need to repair, you need to repair with professional tools.
Overhaul of explosion-proof distribution box:
1. First, disassemble the packaging of the explosion-proof distribution box. According to the data on the design drawing and the manual, carefully check the quantity and specifications, check whether it meets the requirements, whether there is damage or rust, and check whether the spare parts are complete. In case of damage, the location and extent of the damage should be recorded, or a photo should be taken for proof.
2. After opening the box, check the technical information documents such as the factory certificate, manual and internal wiring diagram. After the high-voltage distribution box is unpacked, the distribution box number is sequentially transferred according to the design drawings, and then moved into the installation position in the substation for later installation.
3. After the explosion-proof distribution box is placed on the channel steel, use the thin horn to coarsely adjust the high-voltage box, and then adjust the rest based on one of them, so that the whole high-voltage cabinet has the same surface and uniform clearance. After the bolts are fixed, the cabinets are kept 2 to 3 slits. Finally, the cabinets are permanently fixed to the foundation channel by fixing bolts or welding methods. For the sake of beauty, the welds should be welded to the inside of the cabinet, and no less than 4 places, each length is 80-100~. If the welding part or the distribution box is easily accessible, there is a sharp place that is sharp or easy to cut, and it is polished with a sander or sandpaper until the hand touches it without feeling obvious.
4. Connect the busbars. The main busbar and instrument on the high-voltage power distribution cabinet are provided by the switch factory, or can be made according to the design drawings at the construction site. The connection of the main busbar, the connection between the main busbar and the lower busbar, and the connection between the busbar and the instrument are bolted. The electric compound grease should be applied at the connection surface of the busbar. The tightening degree of the bolt and the connection state of the connecting surface are determined by the torque wrench. Torque values ​​are tightened to control the bolts.