There are a lot of small knowledge in the field of wire and cable, even the cable person may not know! If you don't believe me, read on!

1. What kinds of commonly used wires and cables are divided into according to their uses?

Answer: it can be divided into bare wire, insulated wire, heat-resistant wire, shielded wire, power cable, control cable, communication cable, radio frequency cable and so on.

2. What kinds of insulated wires are there?

Answer: often the insulated wire has the following kinds: PVC insulated wire, PVC insulated flexible wire, nitrile soft PVC compounds insulation wire, rubber insulated wire, agricultural underground buried plastic insulation aluminum core wire, rubber insulation cotton textile soft wire, PVC insulated nylon sheathed wire, electric power and lighting soft PVC insulated wire and so on.

3. What provisions should be followed when selecting the cross section of power cables?

Answer: The selection of power cables should follow the following principles:

(1) The rated voltage of the cable shall be 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 wire core section should meet the stability requirements of the power supply system in the case of short circuit;

(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 shall enable the protection device to operate reliably.

4. What are the advantages of XLPE cable and oil paper cable?

(1) Easy to install, because it allows a small minimum bending radius and light weight;

(2) It is not restricted by line drop;

(3) Good thermal performance, high allowable working temperature and large transmission capacity;

(4) cable accessories are simple, all are dry structure;

(5) Simple operation and maintenance, no oil leakage problem;

(6) Low price;

(7) High reliability and low failure rate;

(8) Less manufacturing process, simple technology, remarkable economic benefits.

5. What are the biggest characteristics and advantages of the following heat-shrinkable cable head accessories?

A: the biggest characteristic of heat shrinkable accessories is to use stress pipe instead of the traditional stress cone, it not only simplifies the construction process, but also reduces the size of the joint terminal, convenient installation, save time and labor, superior performance, saving metal. Heat shrinkable cable accessories are integrated with pouring type and dry package type, which combine the advantages of the two kinds of accessories.

6. What inspection work should be carried out before cable laying?

(1) The bracket should be complete and the paint should be complete.

(2) Cable type, voltage and specification meet the design.

(3) the cable insulation is good, when there is doubt about the seal of the oil-paper cable, the damp judgment should be made; Directly buried cables and small bottom cables should pass the DC voltage test. The oil sample of the oil filled cable shall pass the test.

(4) The oil pressure of the oil-filled cable should not be lower than 1.47MPa.

7. When there is doubt about the seal of oil paper insulated power cable, how to use a simple way to check whether the cable insulation paper is damp?

Answer: ignite the cable insulating paper or put it in the cable oil of about 150℃ for inspection, no "hiss" sound or white foam appears, indicating that it is not affected with moisture.

8. What content should be indicated on the cable marking plate? What are the writing requirements?

A: The cable line design number, cable model, specification and starting point should be indicated on the marking board. The cable used in parallel should have serial number. Requirements for clear handwriting, not easy to fall off.

9, the production of cable joint with yellow silk ribbon, black glass lacquered tape, non-alkali glass ribbon, etc., before the construction of how to carry out moisture treatment?

(1) Constant temperature drying method: roll the insulating strip into small rolls with a diameter of 25~30mm, put them into a constant temperature drying oven at 110~120℃ to dry for 4~5h, cool and dry them, and put them into a dry sealed cylinder.

(2) Oil immersion and moisture removal method: put the small coil of the insulating strip into the cable oil at a constant temperature of 120~130℃, keep a 30mm distance from the bottom of the pot, take it out after a certain time after the oil surface no longer produces foam, and put it into the barrel containing the cable oil. The oil level should exceed all the objects loaded and sealed.

10. What is the function of the cable inner sheath?

Answer: so that the insulation layer will not contact with water, air or other objects, to prevent the insulation from moisture and insulation layer from mechanical damage.