What Do You Know About The Causes Of Cable Heating?

When power cables pass through a certain load current, they will definitely generate heat. As the load current increases, the surface temperature of the cable will become higher. If not dealt with in a timely manner, the consequences can be imagined. For example, polyvinyl chloride (PVC) cables are designed with a core temperature limit of 70 degrees Celsius, resulting in a surface temperature drop of 5-10 degrees Celsius. So it is basically safe for the surface temperature of the cable to be below 60 degrees. From the perspective of power maintenance, the lower the temperature, the better.
The reasons for the heating of power cables during operation are as follows:
1. The resistance of the cable conductor does not meet the requirements, causing the cable to generate heat during operation.
2. Improper selection of cable model results in the conductor cross-section of the cable being too small, causing overload during operation. After prolonged use, the cable's heating and heat dissipation become unbalanced, leading to overheating.
3. When installing cables, they are arranged too densely, resulting in poor ventilation and heat dissipation, or the cables are too close to other heat sources, which affects the normal heat dissipation of the cables and may also cause heating during operation.
4. Poor joint manufacturing technology and loose crimping can result in excessive contact resistance at the joint and also cause heating of the cable.
5. The insulation performance between cable phases is poor, resulting in low insulation resistance and heat generation during operation.
6. The partial sheath of the armored cable is damaged, causing slow damage to the insulation performance after water ingress, resulting in a gradual decrease in insulation resistance and also causing heating during cable operation.
After the power cable generates heat, if the cause is not found and the fault is not eliminated in a timely manner, the cable will continue to operate continuously with electricity, resulting in insulation thermal breakdown. Causing phase to phase short circuit tripping of cables, which may seriously lead to fire.