Carrying capacity of high and low voltage cables

High and low voltage cable carrying capacity in principle is not the same. High voltage cable current carrying capacity should be slightly lower than the voltage cables.

1. Because the high and low voltage cable insulation thickness is different, so the cable conductor of heat dissipation (heat) effect is different because the carrying capacity of the cable depends on the size of the insulating material itself can withstand the conductor temperature rise, that is to say, the rise of temperature of the conductor cannot exceed normal allows the temperature of the insulating material or insulation will be destroyed. The conductor of heat dissipation is very important, of course, the thicker the relative thermal insulation is bad, the relative allows carrying capacity will be smaller.

2. And on the other hand, to consider the heat resistance, insulation materials such as high voltage cable of cross-linked polyethylene insulation used normal allowed working temperature is 90 ° C, normal and low voltage cable polyethylene, polyvinyl chloride (PVC) allowed working temperature is 70 ° C, so for the same cross-section of conductor with cross-linked polyethylene insulation than using polyethylene, polyvinyl chloride (PVC) allows the carrying capacity of the insulation.

All in all, high and low voltage cable carrying capacity depends on the kind of structure, using the insulation of the cable, the cable's external temperature, cable laying conditions, and other factors. Generally in cable design according to the structure and properties of cable load flow calculation, the calculation is relatively complex, because the consideration is more, now wires carrying capacity of the manual provided by carrying capacity is on the basis of the calculation, after the actual test and using test summary, usually, the carrying capacity of the cable is called the reference current carrying capacity, because of the way the same cable laying, use of environmental temperature and the external cooling condition is not the same as the allows the carrying capacity of the cable is not the same.