:2021-01-16 :205
According to the different environments in which wires and cables are installed or stored, we have summarized the following 6 points that need to be paid attention to:
First, under the eaves: ordinary LAN cables can be used only when the cables are not directly exposed to sunlight or very high temperatures, and pipes are recommended.
Second, the external wall: It should be prevented from direct sunlight on the wall and man-made damage to the cable.
Third, in the pipeline: pay attention to whether the plastic pipeline is damaged and the thermal conductivity of the metal pipeline.
Fourth, suspended applications/overhead cables: the sag and gravity of the cable should be considered. Pay attention to the correct use of bundling methods, whether the cables are exposed to yang, high temperature resistance (flame retardant).
Fifth, laying directly in the underground cable trench, this kind of environment is the smallest in the scope of manipulation. The installation of the cable trench shall be checked regularly for dryness or moisture level.
Sixth, underground pipeline: it is convenient for future cable replacement and isolation from the surface pressure and surrounding environment, and the auxiliary pipeline is isolated. But pay attention to keep the pipeline dry.
What are the faults caused by improper installation or storage of wires and cables? What are the common causes?
1. External force damage Judging from the operation analysis in recent years, a considerable number of cable faults are now caused by mechanical damage caused by external force.
2. The insulation is damp. This situation is also very common, and it usually occurs at the cable joints in direct burial or piping.
3. Chemically corroded cables are directly buried in areas with acid and alkali effects, which will often cause the cable armor, lead skin or outer protective layer to be corroded. The protective layer suffers from chemical corrosion or electrolytic corrosion for a long time, causing the protective layer to fail and the insulation to decrease. , Resulting in cable failure.
4. For long-term overload operation, due to the thermal effect of the current, the load current will inevitably cause the conductor to heat up when the load current passes through the cable. At the same time, the skin effect of the charge and the loss of the insulation medium will also generate additional heat, which will increase the temperature of the cable and cause failure.