Some electrical designers can’t distinguish the concepts of flame-retardant cables and fire-resistant cables, and don’t know much about the structure and characteristics of the two, which leads to the inability to correctly design and select these two cables according to the power supply requirements, and carry out design agency or supervision work on site It is impossible to correctly guide the laying construction of these two cables. the

Flame retardant cable refers to the cable that: under the specified test conditions, the sample is burned, and after the test fire source is removed, the spread of the flame is only within a limited range, and the residual flame or residual flame can extinguish itself within a limited time. Its fundamental characteristics are: it may be burned out and cannot operate in case of fire, but it can prevent the spread of fire. In layman’s terms, if the cable catches fire, it can limit the combustion to a local area without spreading, keep other various equipment, and avoid greater losses.

Structural characteristics of flame retardant cables

The structure of the flame-retardant cable is basically the same as that of the ordinary cable, the difference is that all or part of its insulation layer, sheath, outer sheath and auxiliary materials (taping and filling) are made of flame-retardant materials.

Fire-resistant cable refers to: under the specified test conditions, the sample is burned in the flame, and the performance can still maintain normal operation within a certain period of time. Its fundamental characteristic is that the cable can still maintain the normal operation of the line for a period of time under burning conditions. In layman’s terms, in case of fire, the cable will not burn immediately, and the circuit is safer.

Structural characteristics of fire-resistant cables

The structure of the fire-resistant cable is basically the same as that of the ordinary cable. The difference is that the conductor of the fire-resistant cable is a copper conductor with good fire resistance (the melting point of copper is 1 083 ° C), and a fire-resistant layer is added between the conductor and the insulating layer. The refractory layer is made of multi-layer mica tapes. Because the allowable working temperature of different mica tapes varies greatly, the key to cable fire resistance is the mica tape.

Therefore, the main difference between fire-resistant cables and flame-retardant cables is that fire-resistant cables can maintain normal power supply for a period of time when a fire occurs, while flame-retardant cables do not have this feature. This feature determines that fire-resistant cables play an important role in modern urban and industrial buildings.

Because once a fire breaks out, the power supply circuits of control, monitoring, guidance and alarm systems must maintain normal operation. Therefore, the cable is mainly used in the power supply circuit from the emergency power supply to the user’s fire-fighting equipment, fire alarm equipment, ventilation and smoke exhaust equipment, guide lights, emergency power sockets, and emergency elevators.