What is a flame retardant cable? What are the character […]
What is a flame retardant cable? What are the characteristics of flame retardant cables?
The flame-retardant cable refers to the cable that is burned under the specified test conditions. After the test fire source is removed, the flame spreads only within the limited range, and the residual flame or residual burn can be self-extinguished within a limited time. Xiaobian analyzes the fundamental characteristics of flame-retardant wires: in the case of fire, it may be burned out and cannot run, but it can prevent the spread of fire. In layman's terms, if the cable is in a fire, it can limit the combustion to a local extent, without spreading, and keep other equipment to avoid further losses.
The following are the precautions for analyzing the characteristics, classification and selection of flame-retardant wire and cable:
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 difference is that the insulation layer, the sheath, the outer sheath and the auxiliary materials (packing and filling) are all or partially 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 two categories: halogen-containing flame-retardant cables and halogen-free low-smoke flame-retardant cables.
The insulating layer, the sheath, the outer sheath and the auxiliary materials (including and filling) of the halogen-containing flame-retardant cable are all or partially made of halogen-containing polyethylene (PVC) flame retardant material, and thus have good flame retardant properties. Xiaobian suggests that a large amount of smoke and halogen acid will be released when the cable is burned. The halogen acid gas is corrosive to the surrounding electrical equipment. Rescuers need to wear a gas mask to get close to the scene to extinguish the fire. When the cable burns, it will cause harm to surrounding electrical equipment and rescue personnel, which is not conducive to fire fighting and rescue work, resulting in serious "secondary hazard".
According to the provisions of the "Test Methods for Wire and Cable Combustion", the flame-retardant cables evaluated by the bundled burning test method are classified into categories A, B, and C3. The test conditions of the Class A cables are more stringent, and the performance is better than those of the B and C categories. Also more expensive.