If the distribution cabinet wiring can meet this standard, it is really worth the pride of electrici
Electric power workers know that the connection of the distribution cabinet wires accounts for a large proportion of the work of electricians. Most electrician masters have relative specifications for wiring. Almost all wiring is based on the realization of electrical control functions. But looking back, the wiring of electrical distribution cabinets also has certain standards and specifications.
1. Precautions for wiring connection of distribution cabinet:
1. The first is to ensure that the cross-section of the conductor can carry normal working current, and the same heat loss as the components inside the cabinet, so that the temperature must be higher than the outside of the cabinet. For the connection of the control circuit wires, the requirements for the tensile strength under special conditions must also be considered.
2. There are buttons and other components on the door of the control cabinet, which makes it extremely necessary to place a spare line on the cabinet door. Because it is very possible to modify and add circuits to the actual working conditions at the scene, and the wiring harness on the cabinet door is usually protected by a winding tube, which makes it particularly special to add wires to the components on the cabinet door. trouble. Therefore, the color of the spare line is also very conspicuous yellow, so that the circuits added and modified in the cabinet will be clear at a glance.
3. The end of the control line must be treated with a special copper connector and a standard crimping tool that matches it. It is found in the manufacturer that the treatment of the end of the control line actually uses the cutting edge of the oblique pliers for shear crimping or the flat pressing of the force plane of other pliers. However, the biggest problem with these methods is that the crimp quality of each wire-end connector varies greatly with the gripping strength of the wiring staff and the fatigue of the wiring staff's wrist. Excessive holding force will cause the copper connector and the copper wire to be cut together. If the grip is lower, it can only ensure that the copper connector is not separated from the copper wire temporarily. However, these problems will not be found at all during general inspection, which will bring more "test questions" to the complex field repair itself. ". Naturally, there is no guarantee of product quality.
Second, the standard of the wiring of the distribution cabinet:
1. The minimum cross-sectional area of the insulated wire of the power distribution board should be 1.0mm². For low-level electronic circuits, it is allowed to use a cross-section of less than 1.0mm² (but it must not be less than the requirements of the installation section of the electronic equipment manufacturer). When the cross-sectional area is not more than 8mm², the bending radius should be greater than three times its outer diameter. The transition wires of the moving parts such as the panel of the power distribution board should have sufficient windability.
2. The insulation of the connecting wires should be resistant to moisture, mildew and flame. The insulation voltage level is: When the line working voltage is less than or equal to 100V, the insulation voltage level should be greater than or equal to 250V; the line working voltage is greater than 100V and less than or equal to 450V. When the insulation voltage level is greater than or equal to 500V.
3. The wires should be correctly connected to the designated terminals in strict accordance with the drawings.
4. The wiring should be neatly arranged, clear and beautiful, and the wires should be well insulated without damage.
5. The external wiring must not put extra stress on the interior of the appliance.
6. Wiring should be performed in accordance with the markings on the terminals.
7. The diameter of the wire connecting the power indicator is 1.5mm2.
8. The minimum diameter of the single circuit entering the circuit breaker and leakage switch is 1.5mm2.
9. The minimum diameter of the single main circuit is 1.5mm2.
10. The minimum wire diameter of the switch jumper line is 2.5mm2.
11. The minimum wire diameter into the primary winding of the transformer is 1.5mm2.
12. The minimum wire diameter of the control line power supply jumper is 1.5mm2.
13. The minimum wire diameter of the control line is 1.0mm2.
14. The minimum wire diameter from the panel control circuit to the bottom plate is 1mm2.
15. Use 1.5mm2 for voltmeter wire.
16. Use 1.5mm2 for current transformer wire connection.
17. Panel spare wires use 1.0mm2 yellow wires.
18. The lighting cable in the cabinet is 1.0mm2.
19. Multi-core type flexible cord for panel-to-baseboard control wires.
20. Use hard and soft wires for backplane wiring.
21. Special circumstances: PLC, x41, y41 and other connectors can be used 0.3mm2. When the panel and cabinet space is small, it is available, but it must be approved by the person in charge.
22. The main circuit lead, tail and middle are all marked with colored plastic sleeves (yellow, green, red).
23. The color of the power indicator connecting wire matches the power voltage level.
24. The color of the connecting wire of the voltmeter matches the voltage level indicated.
25. The current transformer wire is black. The ends must be covered with insulating sleeves.
26. The end of the connecting wire should generally use a dedicated wire connector. When the terminal structure of the device is a pressure plate insertion type, use a flat-pin copper connector to crimp it before connecting it. When the wire is a single-core hard wire, it is not practical to use a wire connector, and the wire end is made into a ring connector before being connected.
27. If the cross section of the wire entering the circuit breaker is less than 6mm2, when the terminal is a pressure plate type, the wire should be treated as a crimped copper joint to prevent the wire from being scattered. The wire is tied tightly and then connected to the pressure plate.
28. The single-strand copper core wire and single-strand aluminum core wire with a cross-section of 10mm2 or less can be directly connected to the terminals of equipment and appliances.
29. The cores of multi-strand copper core wires with a cross-section of 2.5mm2 or less should be tightened with tinned or crimped terminals before connecting with the terminals of equipment and appliances.
30. For multi-strand aluminum core wires and multi-strand copper core wires with a cross-section greater than 2.5 mm2, in addition to the equipment's own plug-in terminals, the terminals should be soldered or crimped before connecting with the equipment and component terminals.
31. With no connector at the end of the wire: For a plug-in connector, L takes the plug-in length of the plug-in terminal board; for a ring-shaped connector, L takes the length of the ring-shaped connector to an appropriate straight portion. The length of the straight part should be considered according to the radius of the flat washer, so that the flat washer is pressed against the ring joint close to the insulation cut, and is not pressed onto the insulation layer.
32. The size and number of conductors shall meet the design requirements; when there is no design requirement, the total cross-sectional area of the conductors including the insulation shall not be greater than 60% of the cross-sectional area of the trunking.
33. In the trough of the removable cover, the sum of the cross-sectional areas of all the conductors at the wire joint including the insulation layer should not be greater than 75% of the cross-sectional area of the trough; The connector should be placed in the junction box of the trunking.
34. When stripping the insulation layer, the core must not be damaged, and the end faces of the core and the insulation layer should be neat and as perpendicular to the core axis as possible. There must be no oil stains or residue on the core.
35. A special wire stripping tool should be used to strip the insulation of the wire. The wire core should not be damaged, and the unstripped insulation should not be damaged. The cut should be flat.
36. The pressure plate or other special fixtures should match the specifications of the wire core. The fasteners should be tightened in place, and the anti-loosening device should be complete.
37. The wires and electrical components shall be bolted, plugged, welded or crimped, etc., which shall be firm and reliable.
38. The bushing connector, stamper, etc. should match the specifications of the wire core.
39. Before the joint is crimped, the rubber film, residue and oil on the copper core wire should be removed.
40. The winding direction of the ring joint should be the same as the tightening direction of the terminal nut.
41. Check the joint before crimping, and there should be no flaws, such as scars, rust spots, cracks, rips, that prevent use.
42. Except for the special wiring design, all terminal posts in the electrical cabinet must be connected with standard crimping pliers and standard copper connectors.
43. After completing the door panel control line, at least 20% spare lines must be placed, and at least three.
44. The length of the spare line in the cabinet shall be based on the farthest component that can be connected to the cabinet.
45. If the panel has a wireless slot, roll the spare wire into a 100mm diameter coil and secure it with the cable tie at the panel cable tie.
46. The cable cores of the panel and cabinet should be regularly or vertically arranged, and must not be arbitrarily skewed and cross-connected. There should be an appropriate margin for the spare core length.
47. The wiring of the PLC input circuit in the cabinet should not be laid in the same trough as the control line of the main circuit and other voltage level circuits.
48. Avoid connecting several wires to the same terminal, and the joints on general components should not exceed 2 ~ 3. When several wire connectors are connected to the same terminal, the contact should be flat and good.
49. Centralized control consoles should use stranded stranded marine conductors. For the wires transmitting information, necessary anti-interference measures should be taken. The wires should be laid in the cable trough or fixed with a clamping plate. The wires should be connected reliably and there should be relaxation measures.
50. The short wiring of the centrally arranged components such as terminals does not enter the trunking, so as to facilitate inspection and save the wiring space of the trunking.
51. The cables introduced into the cabinet should be arranged neatly, clearly numbered, avoid crossing, and should be fixed firmly, and should not subject the connected terminal block to mechanical force.
52. The grounding jumper wires of the panel and cabinet should not be entangled in the wiring harness.
53. The lighting wires exposed in the cabinet outside the trough must be protected by winding pipes.
54. The exposed part of the panel wiring should be protected by a winding pipe.
55. The rubber-insulated core wire shall be protected by an insulating tube.