What material is flame-retardant cable made of?

1. Flame resistant cable

Click here to get more.

The so-called flame resistant cable is a cable that can maintain normal operation for a certain period of time under specified flame conditions, or a cable that can maintain a complete circuit under burning conditions. The selection of conductor materials, mica tape, insulating materials, and auxiliary materials for flame resistant cables is described as follows.

2. The choice of flame resistant cable materials

(1) Selection of conductor material and conductive core structure

The melting point of aluminum conductor is 685&#;, and the temperature of fire-resistant cables must reach 750&#;. Obviously, aluminum conductors cannot be used as flame resistant cable; the melting point of copper is above 1,000&#;, so it can be used as conductors for flame resistant cable.

Copper wire with a cross-section of 1.0mm2 and below does not melt at high temperatures, but as the core is too thin, it is easy to break due to local overheating and slight external influences, and lose the normal energizing function. Therefore, it is not recommended to use copper wires of 1.0mm2 and below as fire-resistant cables.

The unevenness of the conductor surface will cause great damage to the mica tape, and the performance of the produced flame resistant cable is unstable.

Large cross-section cable sector core conductors are not easy to make flame resistant cable and round core conductors are suitable for fire proof cable. As the surface of the circular structure is smoother than that of the fan-shaped structure, the force of the mica tape is more uniform and will not cause damage to the mica tape, and the circular structure saves the mica tape and has a lower cost than the fan-shaped structure.

(2) The selection of mica tape

According to actual production conditions, phlogopite and synthetic mica are mostly used. The refractory temperature of synthetic mica is higher than that of phlogopite. In actual production, fire-resistant mica tape can be selected according to customer requirements. Considering the safety of flame-resistant cable and ensuring the quality and stability of flame-resistant cable, it is recommended to use synthetic mica.

(3) The selection of insulating materials

The commonly used insulating materials for fire-resistant cables are mostly PVC, PE, XLPE and so on but the effect of using PE and XLPE is better than that of PVC, since at a high temperature of 750+50&#;, the insulating material of the cable has already burned and no longer exists, but different insulation residues have different impacts on the mica tape.

The main components of PVC are PVC resin and CaCO3, which adhere to the outside of the mica tape according to its combustion mechanism. The mixture of its combustion solid residue Cao-CaCl2 is in a relatively stable state and adheres to the outside of the mica tape during the combustion process. It will generate internal stress, squeeze the mica tape, damage the mica tape, and affect the fire resistance.

PE and XLPE are pure hydrocarbons with almost no fillers. The combustion products of CO2 and water vapor escape naturally, and only a small amount of solid impurities remain on the mica tape, which will not cause damage to the mica tape. Therefore, PVC, PE, XLPE can be used for fire-resistant insulation but the PE and XLPE is better.

(4) The selection of auxiliary materials

Although the tape and filling of the auxiliary materials are not the key materials, they should be selected according to the principle of the least residues generation after combustion.

As one of the leading cables manufacturers, Jenuincable can offer the following cables:

ABC cable, Xlpe cable, Yy cable, PVC insulated cable, Fire-rated cables, Orange cable, etc.

Flame retardant cable type performance and advantages

Ordinary flame retardant wire and cable

Ordinary flame-retardant wire and cable insulation and sheathing materials are generally made of halogen-containing (or modified with halogen-containing flame retardants) polymer materials, the most commonly used is polyvinyl chloride (PVC) materials. 

Ordinary PVC resin has extremely high electrical insulation, chemical resistance, wear resistance, aging resistance, and low price. 

It has become the most used cable material in China, but it releases hydrogen chloride when it burns. 

Toxic and harmful gases such as carbon monoxide, carbon dioxide, various aromatic hydrocarbons, and chlorine-containing compounds.

SUNUA Product Page

Low smoke type flame retardant wire and cable

Low-smoke type flame-retardant wire and cable can be added with inorganic hydroxide flame retardants such as aluminum hydroxide or magnesium hydroxide in the insulation and sheath material. 

The flame retardant principle is the principle of condensed phase flame retardant: 

Aluminum hydroxide and magnesium hydroxide are thermally decomposed to release moisture while absorbing heat reduces the actual temperature of the insulation and sheath material, inhibits the decomposition of the material, and releases the combustible gas. 

The resulting metal oxide is a refractory material, and covering the surface of the material can improve the ability of the insulation and the sheath to resist the flame, and the purpose of isolating the air from combustion. 

The advantages of aluminum hydroxide and magnesium hydroxide as flame retardants are as follows: 

Non-toxic, non-volatile, inexpensive, flame retardant, and smoke-free. However, it has poor compatibility with the matrix resin. 

When it is used as a flame retardant, it must be added in a large amount to achieve a certain flame retardant level. 

A large amount of addition may easily lead to a decrease in material formability and mechanical properties.

Low-smoke flame-retardant cables can also incorporate lanthanide compounds into the material. 

The lanthanide compound itself is not a flame retardant, but a flame retardant synergist. 

It is often used in combination with a halide. 

At high temperatures, antimony trioxide reacts with a halide to form lanthanum trihalide or lanthanum oxyhalide. 

The flame retardant principle is The principle of gas phase flame retardation: 

The trihalide bismuth vapor can stay in the combustion zone for a long time and can dilute the flammable gas. 

The tri-halogenated ruthenium has a high vapor density and covers the surface of the polymer, which can play the role of heat insulation and oxygen barrier. 

The combustion of the material is very effective; the decomposition of bismuth oxyhalide is an endothermic reaction, which can effectively reduce the temperature and decomposition rate of the flame retardant material.

The surface effect of the liquid and solid lanthanum trihalide particles can reduce flame energy.

The antimony trihalide can promote the char formation reaction of the condensed phase, relatively retarding the thermal decomposition and oxidative decomposition of the flammable gas-generating material, and the formed carbon layer prevents the combustible gas from entering the flame zone and protecting the underlying material from damage.

Low-smoke halogen-free flame-retardant wire and cable

The insulation and sheathing materials of low-smoke and halogen-free flame-retardant wire and cable are mostly thermoplastic elastomer materials. 

The materials do not contain halogen elements such as chlorobromobromoiodine, etc., and mercury, chromium, cadmium and lead are excluded from the production process. 

Heavy metal elements with large pollution in the environment, are often used as polyamide. The flame retardant mechanism of this cable is to interrupt the exchange of flame retardant mechanism. 

Interrupted exchange of flame retardant means that part of the heat generated when the flame retardant material is burned away so that the material cannot maintain the thermal decomposition temperature, and thus the combustible gas cannot be continuously generated, so the combustion self-extinguishes. 

For example, when the flame retardant material is heated or burned, it can be melted, and when the molten material drops, most of the heat can be carried away, causing the combustion to be delayed, and finally, the combustion may be terminated.

Fluoroplastic flame retardant wire and cable

Fluoroplastic flame-retardant wire and cable are inherently flame-retardant due to the special chemical structure of their materials. 

This kind of material does not need modification or flame retardant treatment and has the characteristics of high-temperature resistance, oxidation resistance, non-flammability, high oxygen index, self-extinguishing, etc. 

It is an ideal line for optical fiber communication cables.

What is the difference between a normal insulated wire and a flame-retardant wire?

The difference between ordinary insulated wire and flame-retardant wire is that the flame-retardant wire has passed the flame-retardant test or certification, while the ordinary cable does not. 

Most ordinary insulated wire and flame-retardant wire have no obvious difference in appearance, but the domestic flame-retardant wire will be in ZR if added to the printed content. 

Foreign standards such as UL are printed with VW-1 or CMP, CMR, etc. depending on the flame retardant level. 

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 a limited range, and the residual flame or residual burn can be extinguished by itself within a limited time. 

The fundamental characteristic is that it may be burnt out in the event of a fire and cannot operate, but it can prevent the spread of fire. In layman's terms, in the event of a fire, the wires can be confined to a local extent without spreading, and other equipment can be saved to avoid further losses.

Contact us to discuss your requirements of Flame Retardant PE Cable Materials Exporter. Our experienced sales team can help you identify the options that best suit your needs.