YTTW - The outer surface of the fire-proof cable is welded rolled strip of copper strip. The inner core insulation of the cable is wrapped by fire-resistant mica tape. Finally, the cable is made of glass fiber or other fire-resistant fillers.

BBTRZ--防火电缆和上面结构一样，就是把耐火云母带换成了陶瓷化硅橡胶带，这两种绝缘不同的电缆我也不知道哪种更好。

BBTRZ - Fire-proof cable is the same as the above structure, which is to replace the refractory mica tape with the ceramic silicone rubber tape. I don't know which of the two different insulated cables is better.

NG-A--防火电缆外护套用的是铝，也就是由铜带纵包焊接轧纹变成了铝带纵包焊接轧纹，里面的缆心可能会多绕几层耐火绝缘带。

NG-A - The outer sheath of fire-proof cable is made of aluminium, that is, from copper strip longitudinal cladding to aluminium strip longitudinal cladding. The inner core of cable may be wound by several layers of fire-resistant insulating strip.