What are the causes of overheating of wires and cables in use?
When wires and cables are powered on, the metal core will generate heat. As the power on time increases, the temperature on the surface of the wires and cables will become higher and higher. If not handled in a timely manner, the consequences can be imagined. The sheath of our commonly used PVC wires and cables is made of PVC, which is considered based on the upper limit of the core temperature of 70 degrees. The surface temperature will be 5 to 10 degrees lower. Therefore, the cable surface temperature below 60 degrees Celsius is fundamentally safe. From the perspective of power supply maintenance, of course, the lower the temperature, the better.
It is normal for wires and cables to overheat, but there are some conditions that may cause wires and cables to overheat. Today, the the Pearl River Cable Editor will talk about the causes of overheating of wires and cables in use.
1、 Causes of overheating of wires and cables in use
1. The wires and cables are not tightly crimped at the joints, resulting in excessive resistance at the joints, which may overheat the wires and cables when powered on for a long time;
2. Inadequate consideration was given to the design, planning, and installation of wires and cables, and wires and cables that did not match the conductor resistance of the cable were selected. When the energized current was greater than this large negative current, overheating would occur;
3. Improper selection of cable type may cause the conductor cross-section of the used cable to be too small, resulting in overload during transportation. After long-term use, the heating and heat dissipation imbalance of the cable may cause overheating;
4. Due to the unprofessional installation personnel, the arrangement of cables during installation is too dense, the ventilation and heat dissipation effect is not good, or the cables are too close to other heat sources, affecting the normal heat dissipation of the cables, which may also cause overheating of the cables during operation;
5. Poor interphase insulation performance of cables leads to low insulation resistance and overheating during transit;
6. The partial sheath of armored cables is damaged, causing slow damage to the insulation performance after water ingress, resulting in a gradual decrease in insulation resistance, and also causing overheating during cable operation;
7. Many inferior wires and cables on the market have poor insulation, resulting in a decrease in insulation resistance, which can cause overheating during prolonged operation;
8. Improper selection of wire and cable models, such as fire resistant wire and cable should be selected in high temperature or flammable environments.