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 - 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
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.