低倍过载聚氯乙烯电线的火灾危险性研究

Fire Hazard Study of PVC Wire under Low Times of Overload Condition

分析了低倍过载条件下聚氯乙烯电线绝缘材料的热分解特性和绝缘性能,研究过载状态下电线的火灾危险性。结果表明:经过载老化的电线较未加载电线的热解燃烧危险性减小,绝缘性能降低;样品的质量损失率与热失重第一阶段关联较大,第二失重阶段只是一些结构的重整;过载倍数越高,电线的热解燃烧危险性越小,绝缘性能越差;1.5倍穿管电线绝缘材料的火灾危险性较小。

The thermal decomposition characteristic and insulating properties of the polyvinyl chloride （PVC） wire insulating material under low times of overload condition were analyzed to study the fire hazard of the wire. The results show that compared with the new wire, the fire hazard of pyrolysis of the overloaded wire reduces, and the insulating properties decrease. The mass loss rate of the sample is asso- ciated with the first TG stage, while the second TG stage is just some reforming of structure. The high- er the overload ratio, the smaller the fire hazard of pyrolysis is, and the poorer the insulating properties are. The fire hazard of the wire protected by flame-retardant PVC conduit under 45 A overload current is smaller.