System category A——This category comprises those systems in which any phase conductor that comes in contact with earth or an earth conductor. is disconnected from the system within 1 min.
System category B ——This category comprises those system which,under faultconditions,are operated,are operated for ashorttimewith one phase earthed.This period should not exceed 1 h..Fora longer period, not exceeding 8h on any occasion, can be tolerated.The total duration of earth faults in any year should not exceed 125h.
System categeory C——This category comprises all systems which do not fall into A and B
电缆的型号Type of cable
型号 Type 名称 Designation 适用范围 Application
YJV 铜芯交联聚乙烯绝缘氯乙烯护套电力电缆 Copper conductor,XLPE insulated and PVC sheathed power cable 室内、隧道及电缆沟等场所,不能承受机械外力。单芯电缆不允许敷设在磁性管道中。 For laying indoors 、 intunnel or cable trench,unable to bear external mechan-icalforces.Single-core cable in magnetic duct is not permissible
YJLY 铝芯交联聚乙烯绝缘乙烯护套电力电缆 Aluminium conductor, XLPE insulated and PVC sheathed power cable
YJY 铜芯交联聚乙烯绝缘氯乙烯护套电力电缆 Copper conductor ,XLPE insulated and PEsheathed power cable