Views:1 Author:Site Editor Publish Time: 2021-11-22 Origin:Site
In recent years, in the global power system fire accidents, the proportion of power system power supply interruptions caused by power cables on fire has been on the rise. Therefore, it is increasingly important to use flame-retardant cables to prevent fire from spreading in power plants, substations and other places where there are a large number of electrical equipment and a large number of cables are densely laid. However, some electrical designers are not clear about the concept of flame-retardant cable and fire-resistant cable, and do not know the structure and characteristics of the two. As a result, they cannot properly design and select these two cables according to the power supply requirements. Design agency or supervision on site The laying workers of these two types of cables cannot be properly guided during work. Therefore, a comprehensive and correct understanding of flame-retardant and fire-resistant cables is the first condition for the correct selection of them.
1. Flame retardant cable
Flame-retardant cable refers to a cable whose sample is burned under specified test conditions, and after the test fire source is removed, the flame spreads only within a limited range, and the residual flame or residual burn can be extinguished by itself within a limited time. Its fundamental feature is: it may be burned out in a fire and cannot operate, but it can prevent the spread of the fire. In layman's terms, if a cable catches a fire, it can limit the combustion to a local area without spreading, so as to protect other equipment and avoid greater losses.
2. Fire-resistant cable series
Fire-resistant cable refers to: under the specified test conditions, the sample is burned in the flame and can still maintain the performance of normal operation for a certain period of time. Its fundamental characteristic is that the cable can still maintain the normal operation of the line for a period of time under burning conditions. In layman's terms, in case of fire, the cable will not burn at once, and the circuit is safer. Therefore, the main difference between fire-resistant cables and flame-retardant cables is: fire-resistant cables can maintain normal power supply for a period of time when a fire occurs, while flame-retardant cables do not have this feature. This feature determines that fire-resistant cables play an important role in modern cities and industrial buildings, because once a fire occurs, the power supply loops of the control, monitoring, guidance and alarm systems must maintain normal operation. Therefore, the cable is mainly used in power supply circuits from emergency power supply to user fire-fighting equipment, fire alarm equipment, ventilation and smoke exhaust equipment, guide lights, emergency power sockets, and emergency elevators.