The power cable passes through a certain load current, it will be hot. As the load current increases, the surface temperature of the cable will be higher. If it is not handled in time, the consequences can be predicted.For example, polyvinyl chloride (PVC) cable is considered at the upper limit of 70 degrees of core temperature, and the surface temperature will be 5 ~ 10 degrees.Therefore, the surface temperature of the cable is basically safe under 60 degrees, and the lower the temperature is, of course, the better.The reasons for heating in operation are as follows:
1. The cable conductor resistance does not meet the requirements, Causes the cable to produce heat in operation.
2. The improper selection of cables causes the conductor cross section of the used cable to be too small, and the operation produces an overload phenomenon. After a long period of use, the heating and heat dissipation of the cable cause the heating phenomenon.
3. Cable installation is too dense,The ventilation is not good, or the cable is too close to other heat sources. It affects the normal heat dissipation of the cable, and also may cause the cable to generate heat during operation.
4. The joint manufacturing technology is not good, the pressure is not tight, and the contact resistance of the contact is too large, which also causes the heating of the cable.
5. The insulation resistance of the cable is not good, and the insulation resistance is small.
6. The local sheath of the armored cable is damaged, and the insulation performance is slowly destroyed after the water is flooded, resulting in the gradual reduction of the insulation resistance and the heating phenomenon in the operation of the cable.
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