Some electrical designers are not clear about the concepts of flame retardant cables and fire-resistant cables, and do not understand the structure and characteristics of the two cables, which leads to the failure to choose and design these two cables correctly according to the requirements of power supply, and the failure to guide the laying of these two cables correctly in the field of design agents or supervision.
1. What is the flame retardant cable?
Flame-retardant cable refers to the cable in which the sample is burned under the specified test conditions, and the flame spread only within a limited range after the removal of the test flame source, and the flame or flame can go out by itself within a limited time.Its fundamental characteristics are: in the case of fire may be burned out and cannot operate, but can prevent the spread of the fire.Generally speaking, in case of a fire, the cable can limit the combustion to a local area without spreading, so as to save other kinds of equipment and avoid causing greater losses.
2. Structural characteristics of flame retardant cable
The structure of the flame retardant cable is basically the same as that of the ordinary cable, except that the insulation layer, sheath, outer sheath and auxiliary material (wrapping and filling) are all or part of the flame retardant material.
3. What is fire-resistant cable?
Fire-resistant cable refers to the performance that the sample can maintain normal operation in a certain period of time when it is burned in flame under specified test conditions.Its fundamental characteristic is that the cable can maintain the normal operation of the line for a period of time under the condition of combustion.In common terms, in case of fire, the cable will not burn, the loop is safer.
4. Structural features of fire-resistant cable
The structural characteristics of fire-resistant cable and ordinary cable are basically the same, the difference is that the conductor of fire-resistant cable USES copper conductor with good fire-resistant performance (the melting point of copper is 1 083℃), and between the conductor and insulation layer add fire-resistant layer.The refractory layer is composed of multiple layers of mica tape.Because the allowable working temperature of different cloud master tapes varies greatly, the key to the fire resistance of cables is mica tapes.
The main difference
Therefore, the main difference between fire-resistant cable and fire-retardant cable is that fire-resistant cable can maintain normal power supply for a period of time in case of fire, while fire-retardant cable does not have this characteristic.This characteristic determines that fire-resistant cable plays an important role in modern urban and industrial buildings.
In case of fire, the power supply circuit of the control, monitoring, guidance and alarm system must be maintained in normal operation.Therefore, this cable is mainly used in power supply circuits from emergency power supply to user's fire fighting equipment, fire alarm equipment, ventilation and smoke exhaust equipment, guidelights, emergency power sockets, emergency elevators and other power supply circuits.