22. Wire and cable products are mainly divided into five categories:
1) Bare wires and bare conductor products
The main characteristics of this kind of products are: pure conductor metal, no insulation and sheath layer, such as steel reinforced aluminum stranded wire, copper aluminum bus bar, electric locomotive line, etc.; the processing technology is mainly pressure processing, such as smelting, calendering, drawing, stranding / pressing stranding, etc.; the products are mainly used in suburban, rural, user main line, switch cabinet, etc.
2) Power cable
The main features of this kind of products are: the insulation layer is extruded (wound) outside the conductor, such as overhead insulated cable, or several core stranded (corresponding to the phase line, neutral line and ground wire of power system), such as overhead insulated cable with more than two cores, or additional sheath layer, such as plastic / rubber sheathed wire and cable. The main process technologies include drawing, stranding, insulation extrusion (wrapping), cabling, armor, sheath extrusion, etc. the different process combinations of various products have certain differences.
Products are mainly used in power generation, distribution, transmission, transformation, power supply lines in the power transmission, through the current (dozens of a to several thousand a), high voltage (220 V to 500 kV and above).
3) Wires and cables for electrical equipment
The main characteristics of this kind of products are: various specifications, wide range of applications, and more use voltage of 1kV and below. In the face of special occasions, new products are constantly derived, such as fire-resistant cable, flame retardant cable, low smoke and halogen-free / low smoke and low halogen cable, termite proof, rat proof cable, oil / cold resistant / temperature resistant / wear-resistant cable, medical / agricultural / mining cable, thin-wall wire, etc.
4) Communication cable and optical fiber
With the rapid development of communication industry in the past 20 years, the product also has an amazing development speed. From the simple telephone and telegraph cable in the past, it has developed to thousands of pairs of voice cable, coaxial cable, optical cable, data cable, and even combined communication cable.
This kind of product structure size is usually small and uniform, and the manufacturing precision is high.
5) Electromagnetic wire (winding wire)
It is mainly used in various motors, instruments and meters.
Wire and cable derivatives / new products:
The derivative / new products of wire and cable are mainly produced by adopting new materials, special materials, changing product structure, improving process requirements, or combining different varieties of products due to different application occasions, application requirements, convenience of equipment and requirements for reducing equipment cost.
Different materials are used, such as flame retardant cable, LSZH / LSZH cable, termite proof cable, mouse proof cable, oil / cold / temperature resistant cable, etc;
Change product structure, such as: fire resistant cable, etc;
Improve process requirements, such as: medical cable, etc;
Combined products such as OPGW, etc;
It is convenient to install and reduce equipment cost, such as prefabricated branch cable.
23. List the cable racks you are familiar with.
Answer: tailor welded E-frame, fabricated E-frame, bridge cable rack, cable bracket, hook type bracket, single cable support, etc.
24. What requirements should be met for cable laying?
A: the following requirements should be met:
1) In terms of safe operation, all kinds of external damage should be avoided as far as possible to improve the power supply reliability of cable lines;
2) In terms of economy, we should consider the least investment;
3) In terms of construction, the route of cable line must be convenient for construction and maintenance after commissioning.
25. What are the insulation materials for making cable terminal or intermediate joint?
Answer: there are insulating glue, insulating tape, insulating pipe, insulating gloves, insulating resin, etc.
26. What are the requirements for the arrangement of cables?
1) Power cable and control cable shall not be arranged on the same layer of support.
2) High and low voltage cables, strong and weak current control cables shall be arranged in layers according to the required sequence. Generally speaking, they should be arranged from top to bottom. However, when high-voltage cables above 35kV are introduced into the cabinet panel, they can be configured from the bottom to meet the bending radius.