N2XH IEC 60502-1 XLPE FRNC 0.6/1kV Cable Voltage (Uo/U) 600/1000V Product Category 1. Ordinary flame retardant cable: In the event of fire, the cable may produce a large amount of corrosive gases and smoke after combustion, and can be used in general occasions with low flame retardant requirement. Its flammability has A, B,C, D four categories, and its cable models are added with ZRA- (or ZA-), ZRB- (or ZB-), ZRC- (or ZC-), and ZRD- (or ZD-) before ordinary cable models,