The influence of temperature on current carrying capacity

    The current carrying capacity refers to the current value that can be carried in the conductor, and generally refers to the current value in normal operation. Generally, it is related to the conductor's resistivity, cross-sectional area, length, shape and other factors, which are the physical characteristics of the conductor itself. However, during specific use, temperature also has an effect on the current carrying capacity. Specifically, the higher the temperature, the smaller the current carrying capacity. How can this be understood?

    For general conductors, we cannot ignore its internal resistance, even if its internal resistance is very small. When a current flows, the conductor itself heats up, which will cause the temperature of the conductor to rise. When we use electrical equipment with relatively large power, we generally choose a cable with a relatively large cross-sectional area, that is, to reduce the internal resistance of the cable and reduce the heat generation of the cable itself. The outside of the cable should also have good heat dissipation. If the cables are concentrated or run through pipes, cables with larger cross-sections should generally be selected.

    The outside of the cable is covered with insulating material. The PVC material of low-temperature cable generally can withstand a temperature of about 70℃, and some high-temperature cables and special cables can withstand more than 200℃ after using temperature-resistant insulating materials. Whether it is the heating of the conductor itself or the ambient temperature, from a safety point of view, we need to control the temperature of the insulating layer and the conductor in a lower temperature range.

    (huiputech)