1、Categorization of insulated wires
A: There are often insulated wires as follows: PVC insulated wires, PVC insulated flexible wires, nitrile PVC mixture insulated flexible wires, rubber insulated wires, agricultural underground directly buried aluminum core plastic insulated wires, rubber insulated cotton yarn textile flexible wires, PVC insulated nylon sheathed wires, PVC insulated flexible wires for power and lighting, and so on.
2, cable tray is suitable for what occasions?
A: cable tray is suitable for general industrial and mining enterprises indoor and outdoor overhead laying of power cables, control cables, can also be used for telecommunications, radio and television broadcasting and other departments in the indoor and outdoor erection.
3, the types of cable accessories
A: Commonly used electrical accessories are cable terminal junction box, cable intermediate junction box, connecting tubes and terminals, steel wiring troughs, cable bridges and so on.
4, the meaning of the cable intermediate joints
A: Connecting the cable and cable conductor, insulation shield and protective layer, in order to connect the cable line device, known as the cable intermediate joints.
5, what is the main electrical connector?
A: The main electrical wiring is a power plant, substation in the main electrical equipment and bus connection, including the main bus and plant power system according to certain functional requirements of the connection.
6, in the selection of power cable cross-section, which provisions should be followed?
A: The selection of power cables should comply with the following principles:
(1) the rated voltage of the cable should be greater than or equal to the rated voltage of the power supply system at the point of installation;
(2) The continuous allowable current of the cable should be equal to or greater than the maximum continuous current of the power supply load;
(3) Core cross-section to meet the requirements of the stability of the power supply system in the event of a short circuit;
(4) According to the length of the cable to check whether the voltage drop meets the requirements;
(5) The minimum short-circuit current at the end of the line should be able to make the protective device operate reliably.
7, cross-linked polyethylene cables and oil paper cables compared to what are the advantages?
A: (1) easy to install, because it allows a small minimum bending radius, and light weight;
(2) not subject to line drop limitations;
(3) Good thermal performance, high allowable operating temperature, and large transmission capacity;
(4) Simple cable accessories, all dry structure;
(5) Simple operation and maintenance, no oil leakage;
(6) Lower price;
(7) High reliability, low failure rate;
(8) less manufacturing processes, simple technology, significant economic benefits.
8, fixed AC single-core cable clamp has what requirements? Why?
A: The fixture should be free of iron to form a closed magnetic circuit, this is because when the cable core through the current, the magnetic lines of force generated around it, the magnetic lines of force and the size of the current through the core is directly proportional to the use of iron and other magnetically conductive materials, according to the electromagnetic induction can be seen in the iron will produce eddy currents in the cable heating, or even burned out of the cable. So do not use iron for single-core AC cable fixed fixture.
9、What are the biggest features and advantages of the following accessories for heat-shrinkable cable head?
A: The biggest feature of heat shrinkable accessories is to replace the traditional stress cone with stress tube, which not only simplifies the construction process, but also reduces the size of the terminal of the connector, easy to install, saves time and labor, has superior performance and saves metal. Heat-shrinkable cable accessories combine the advantages of both pouring type and dry-packing type into one.