Today's brief introduction Fireproof cable The classification is mainly based on different structures. Let's first understand the two major structural components of cables: conductors and insulators
1、 Cables mainly have copper conductors:
Conductor can be divided into bare copper, copper plating, copper clad steel, copper alloy, copper foil wire, etc.
Bare copper --- Low conductor resistance, easy to oxidize copper plating --- Enhanced oxidation resistance
Tinned copper --- Enhanced oxidation resistance for subsequent welding of silver plated copper --- High conductivity, high price, mostly used for RF cable and fluoroplastic high-temperature wire
Copper clad steel --- High strength, commonly used for overhead cables
copper alloy --- High strength (a small amount of other metals are added to copper)
tinsel --- Strong bending resistance and high flexibility (copper is pressed into thin sheets and wrapped on elastic fibers)
In order to improve the strength of the conductor, it is usually adopted to Stranding method
2、 Cable insulator:
Common insulation materials include PVC （ PolyVinyl Chloride , PVC ) 、 SR-PVC （ Semi-rigid PVC , semi hard PVC ）、 PP (Polypropylene , polypropylene) PE （ Polyethylene , polyethylene) Foam-PE 、 Foam-PE+Skin And the latest magnesium oxide（ MI ）Mineral insulator.
3、 Type of fireproof cable:
YTTW-- The outside of the fireproof cable is copper strip longitudinally wrapped and welded, and the inner cable core insulation is wrapped with fire-resistant mica tape. Finally, the cable is formed with glass fiber or other fire-resistant fillers.
BBTRZ-- The fireproof cable has the same structure as the above one, that is, the fire-resistant mica tape is replaced by the ceramic silicone rubber tape. I don't know which of the two cables with different insulation is better.
NG-A-- The outer sheath of the fireproof cable is made of aluminum, which means that the longitudinal wrapped welding of copper strip has changed into the longitudinal wrapped welding of aluminum strip. The cable core inside may be wrapped with several layers of fire-resistant insulating tape.
BTLY-- The external protection of the fireproof cable adopts continuous extrusion aluminum tube, and the internal cable core protection is also continuous extrusion coated aluminum tube. The aluminum tube protection inside and outside the cable is polished rod, without rolling lines. The bending performance of this cable must be free of longitudinal cladding welding and rolling lines Flexible fireproof cable 。
BTTZ-- Mineral insulated cable is also called magnesium oxide cable. This cable should have good fireproof performance, but the production process is very complicated, mainly because the filling of magnesium oxide powder is difficult, and the equipment for producing this cable cannot be localized, mainly by introducing advanced technology and equipment.
