With the development of social economy, our daily life is inseparable from the use of wires and cables, however, some times, due to our improper use of wires and cables, resulting in many fires. Therefore, the use of fireproof wires and cables is a crucial step. According to the characteristics of the cable itself, fire-resistant wire and cable can be divided into flame-retardant cable and fire-resistant cable. So, do you know the difference between flame retardant cable and fire resistant cable? Next, I will tell you.
Flame retardant cable refers to: under the specified test conditions, the sample is burned, after removing the test fire source, the flame only spreads in a limited range, and the remaining flame or residual combustion can extinguish itself in a limited time. In the category of wire and cable, it is usually expressed by - Zr, while fire-resistant cable refers to the cable whose sample burns in the flame under the specified test conditions and can maintain normal working performance within a certain period of time. According to the national standard, fire resistant wires and cables can be divided into a and B levels, which are represented by NHA and nhB.
Differences:
1. Their structures and materials are different
The basic structure of flame retardant cable is as follows: (1) flame retardant material is used for insulation layer; (2) flame retardant material is used for sheath and outer sheath; (3) flame retardant material is used for coating and filling.
Fire resistant cable usually adds another layer of refractory between conductor and insulation layer, so in theory, refractory layer can be added to the structure of flame-retardant cable to form flame-retardant and fire-resistant cable.
2. Their working principles are different
The flame retardant principle of halogen cable depends on the flame retardant effect of halogen. The flame retardant principle of halogen-free cable is to reduce the temperature by precipitating water. Fire resistant cable depends on the fire resistance and heat resistance of mica material of fire resistant layer, so as to ensure that the cable can work normally in fire.
3. They have different characteristics.
The basic characteristics of flame retardant cable are: once there is a fire, it will burn out and cannot operate, but it can prevent the spread of fire. Generally speaking, in case of fire, the cable can control the combustion in a local range, without causing diffusion, and keep all kinds of equipment, so as to avoid greater losses.
The basic characteristic of fire-resistant cable is that it can maintain the normal operation of the line for a period of time under the burning condition. Generally speaking, once there is a fire, the cable will not burn out immediately, and the circuit is also good.
The main difference between fire-resistant cable and flame-retardant cable is that fire-resistant cable can maintain normal power supply for a period of time in case of fire, but flame-retardant cable does not have this characteristic. Therefore, fire-resistant cable can replace flame-retardant cable, but flame-retardant cable can not replace fire-resistant cable.
How to determine whether wire and cable products are fire resistant? Is it to see if the wire and cable products themselves go out? No, of course not. "It has nothing to do with the spontaneous combustion of the product. Because in the structure of flame-retardant cable, adding refractory layer to form fire-resistant wire and cable is a kind of both flame-retardant and fire-resistant wire and cable. One of the major functions of fire-resistant wire and cable is the fire resistance of wire and cable products. Fire resistant wires and cables can normally work at 750 ℃ to 800 ℃ for at least 180 minutes.
Well, the above is the difference between flame-retardant cable and fire-resistant cable, I hope you have an understanding.
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