1. What kinds of commonly used wires and cables are classified according to their purposes?
A: According to the use, it can be divided into bare wire, insulated wire, heat-resistant wire, shielded wire, power cable, control cable, communication cable, RF cable, etc.
2. What are the types of insulated wire and cable?
Answer: There are commonly used insulated wires: polyvinyl chloride insulated wire, PVC insulated wire, nitrile polyvinyl chloride mixture insulated cord, rubber insulated wire, agricultural underground direct buried aluminum core plastic insulated wire, rubber insulated cotton yarn Textile cords, PVC insulated nylon sheathed wires, PVC insulated cords for power and lighting, etc.
3. What kind of occasion is the cable tray suitable for?
Answer: The cable tray is suitable for laying power cables and control cables indoors and outdoors in general industrial and mining enterprises. It can also be used for erection indoors and outdoors in telecommunications, radio and television departments.
4. What are the cable accessories?
Answer: Commonly used electrical accessories include cable terminal junction box, cable intermediate junction box, connecting pipe and terminal block, steel plate wiring slot, cable tray and so on.
5, what is the cable intermediate connector
Answer: The device that connects the cable and the conductor of the cable, the insulating shield and the protective layer to connect the cable line is called the cable intermediate connector.
6, what is the electrical main wiring
Answer: The main electrical wiring is the connection method of the main electrical equipment and busbar in the power plant and substation, including the connection method of the main busbar and the plant power system according to certain functional requirements.
7. What regulations should be followed when selecting the cross section of the power cable?
A: The choice of power cable should follow the following principles:
(1) The rated voltage of the cable is greater than or equal to the rated voltage of the power supply system at the installation point;
(2) The continuous allowable current of the cable shall be equal to or greater than the maximum continuous current of the power supply load;
(3) The core section must meet the stability requirements of the short circuit of the power supply system;
(4) Check whether the voltage drop meets the requirements according to the cable length;
(5) The minimum short-circuit current at the end of the line should enable the protection device to operate reliably.
8. What are the advantages of XLPE cable and oil-paper cable?
(1) Easy to install because it allows a small minimum bending radius and is light in weight;
(2) Not subject to line drop*;
(3) Good thermal performance, allowing high operating temperature and large transmission capacity;
(4) The cable accessories are simple and all are dry structures;
(5) Simple operation and maintenance, no oil leakage problem;
(6) the price is lower;
(7) High reliability and low failure rate;
(8) The manufacturing process is small, the process is simple, and the economic benefits are remarkable.
9. What are the requirements for the clamp of the fixed AC single-core cable? why
Answer: The clamp should be free of iron to form a closed magnetic circuit. This is because when the cable core passes current, magnetic flux is generated around it. The magnetic flux is proportional to the current passing through the core. If a magnetic material such as iron is used, Electromagnetic induction knows that eddy currents will be generated in the iron parts to heat the cable and even burn the cable. Therefore, iron parts cannot be used as fixing fixtures for single-core AC cables.
10. What are the biggest features and advantages of the following accessories for heat shrinkable cable heads?
Answer: The biggest feature of the heat shrinkable accessory is that it replaces the traditional stress cone with a stress tube. It not only simplifies the construction process, but also reduces the size of the terminal of the joint. It is easy to install, saves time and labor, has superior performance, and saves metal. The heat-shrinkable cable accessory combines a perfusion and a dry-package, combining the advantages of both accessories.