When wires and cables pass a certain load current, they will definitely generate heat. As the load current increases, the surface temperature of the cable will become higher. If it is not enough, the consequences can be imagined. For example, polyvinyl chloride (PVC) cables, so if the core temperature is capped at 70 degrees, the surface temperature will be 5 to 10 degrees lower. Therefore, the cable surface temperature is basically safe below 60 degrees. From the research on power supply care, of course, the lower the temperature, the better.

The reasons why wires and cables heat up during operation are as follows:

1. The resistance of wires and cables does not meet the requirements, causing the cables to heat up.

2. Improper selection of wires and cables, the cross-section of the cable conductor used is too small, and overload occurs during operation. After being exposed to sunlight for a long time, the cable will heat up due to uneven heat dissipation.

3. When installing cables, they are arranged too densely and the ventilation and heat dissipation effect is not good, or the cables are too close to other heat sources, which affects the normal heat dissipation of the cables and may also cause the cables to heat up during operation.

4. The joint manufacturing process is not good and the crimping is not tight, resulting in excessive contact resistance at the joint and heating of the cable.

5. The insulation function between cable phases is not good, resulting in low insulation resistance and heat generation during operation.

After the wires and cables heat up, if you can't find the cause, quickly remove the obstacles. When the cable is continuously energized, insulation thermal breakdown will occur. A phase-to-phase short circuit trip in the cable may cause a fire.

The construction of wires and cables occupies a small area and is usually buried in the soil or indoors. The area is always very small because after all, it is only the size of the model. So in terms of floor space, it is always very small. Comparing its application process, it can be seen that the design of the cable is still very scientific and unique, and its functions will gradually be improved.

How are wires and cables routed in buildings?

1. Pipeline wiring For new buildings without embedded pipelines, wiring construction can be carried out at the same time as building decoration, which not only facilitates wiring, but does not affect the beauty of the building.

2. Pipes are generally buried from the wiring room to the installation holes of the information sockets. During construction, as long as the twisted pair is fixed at the terminal of the information socket and the cable is pulled out from the other end of the pipe, the wires and cables can be introduced into the wiring room.

3. Cabling in the ceiling

1. Request construction drawings and confirm wiring routes;

2. Open the ceiling along the designed route (i.e. within the cable trough) and push each panel open with both hands;

3. Arrange multiple cable boxes upward parallel to the outlet;

4. Label, the carton can be marked directly, the label of the cable is written on the end of the cable and affixed with a label;

5. Connect the pulling wire of appropriate length to the coil;

6. From the end far away from the wiring room, pull both ends of the cable (tied together) along the cable tray to one end of the ceiling corridor;

7. Move the ladder and throw the cable to the next hole in the ceiling until the rope reaches the end of the corridor;

8. Pull out the cable every 2nd box to make it "right".