The following is the analysis of the characteristics, classification and selection of flame retardant wires and cables:

1. Structural characteristics of flame retardant cable

The structure of the flame-retardant cable is basically the same as that of the ordinary cable. The Chaoyang cable editor reminds that the insulation layer, sheath, outer sheath and auxiliary materials (straps and fillers) are all or partly made of flame-retardant materials.

2. Classification of flame retardant cables

According to the different flame-retardant materials of cables, flame-retardant cables are divided into halogen-containing flame-retardant cables and halogen-free low-smoke flame-retardant cables.

Among them, all or part of the insulation layer, sheath, outer sheath and auxiliary materials (straps and fillers) of halogen-containing flame-retardant cables are made of halogen-containing polyethylene (PVC) flame-retardant materials, so they have good flame retardant properties. The editor reminds that when the cable is burning, a large amount of dense smoke and halogen acid gas will be released. The halogen acid gas has a corrosive hazard to the surrounding electrical equipment. Rescuers need to wear a gas mask to approach the scene to extinguish the fire. When the cable burns, it will cause harm to the surrounding electrical equipment and rescuers, which is not conducive to fire fighting and rescue work, resulting in a serious "secondary hazard".

According to the provisions of "Wire and Cable Combustion Test Method", the flame retardant cables evaluated by the bundled combustion test method are divided into A, B, and C3 categories. Among them, the test conditions of the A cable are more severe, and the performance is better than the B and C categories. Also expensive.

3. Issues to be noted when selecting flame-retardant cables

According to the specific characteristics of the flame-retardant cable, the design and selection of the flame-retardant cable and the installation work should be paid attention to, and the following issues should be noted:

(1) Since halogen-containing flame retardant cables (including flame retardant cables and low halogen low smoke flame retardant cables) will release corrosive halogen acid gas when burning, it greatly hinders the fire fighting work and delays the fire rescue time and aggravates the spread of fire. The editor recommends that halogen-free, low-smoke flame-retardant cables should be designed and selected in public places with high population density. Any kind of flame-retardant cable can be used in the working area with a small population density.

(2) The A, B, and C categories of the flame-retardant cable cannot be distinguished from the appearance. Only the manufacturer guarantees the supply. The editor reminds everyone that the cable manufacturer should be carefully selected when choosing. You can request to provide relevant information.

(3) Compared with halogen-containing flame-retardant cables, halogen-free and low-smoke flame-retardant cables have the advantages of low corrosion and low smoke, but the electrical and mechanical properties are significantly reduced. The editor of Chaoyang Cable suggests that when laying cables, halogen-free Low-smoke flame-retardant cables should have a larger bending radius than halogen-containing flame-retardant cables.

(4) In the design of cable laying, it is not advisable to lay non-flame-retardant cables and flame-retardant cables in parallel, and it is not advisable to lay flame-retardant cables of different flame-retardant types in parallel.