What is the mineral-insulated cable? Why is it so hot?

In recent years, with the rapid development of the city, the subway, stations, hospitals, schools, high-rise residential, and other public facilities to expand the scale of construction, the number of high-rise buildings proliferated, and the city's demand for electricity is rising.

In such densely populated key areas, the consequences of a fire are serious.

 

In 1996, when a serious fire broke out in the Channel Tunnel connecting England and France, the mineral-insulated cable system installed in the tunnel provided emergency lighting for evacuating passengers even after the reinforced concrete and welded rails were destroyed, and withstood the severe test of fire and heat because of the use of mineral insulated cables.

Because mineral-insulated cables have quality and performance that are incomparable to ordinary cables, their use is becoming more widespread.

 

However, according to the analysis of building and safety fire experts, there are still many public facilities selected cables that do not have fire performance, and it is difficult to play the role in the fire.

Many countries in the world even stipulate that the fire protection system in the fire protection design code of building engineering needs to use mineral-insulated cables to pass fire inspection and acceptance.

Because the mineral-insulated cable in the fire conditions can not only ensure that the fire duration (more than 180 minutes) of the fire power supply, but also will not delay combustion, will not produce smoke, and produce secondary disasters, thus winning valuable time for fire rescue.

Today, the ZMS cable editor will introduce you what is mineral insulated cable.

Mineral insulated cable is made of copper conductor, magnesium oxide insulation material, and copper or copper alloy sheath using a special production process, which is non-combustible, smokeless, non-toxic, and fire resistant.

The outer sheath can be made of organic materials to meet the requirements of mineral-insulated cable for halogen-free, low smoke, and flame retardant, and its performance meets the relevant provisions of national standard GB/T13033.

 

It can be said that the mineral-insulated cable is a special cable that must be used for fire fighting in every important facility construction, large public areas, high-rise buildings, and other places in the country.

Its fire resistance, durability, safety, reliability, and economy are irreplaceable by the traditional power cables.

Mineral-Insulated Cable Structure

Mineral insulated cable is a kind of copper sheath-wrapped copper conductor core, and magnesium oxide powder is an inorganic insulation material to isolate the conductor and sheath cable, and the metal core and sheath to form a close whole.

Magnesium oxide is also a non-combustible substance and does not produce toxic smoke or other harmful substances when encountering high temperatures.

Therefore, the cable with magnesium oxide as the insulator of the copper core and copper sheath has better performance and many advantages.

Mineral Insulated Cable Performance and Advantages

Mineral insulated cable mainly has BBTRZ flexible mineral insulated fireproof cable and YTTW flexible inorganic mineral insulated cable series, which has good fire resistance, high-temperature resistance, high load capacity, waterproof, corrosion resistance, mechanical damage resistance, irradiation resistance, electromagnetic compatibility, beautiful and elegant, etc. Meanwhile, the cable will not emit any smoke, halogen, or toxic and harmful gases under fire conditions.

1 Fire Performance

As all mineral cable is composed of inorganic materials, it will not cause fire itself, it is impossible to burn or fuel combustion, not to mention the production of toxic gases.

Even if there is a flame outside the burning, the cable can still work normally.

Mineral-insulated cable is insulated with magnesium oxide, and the melting point of magnesium oxide is as high as 2800 ℃, it is difficult to burn easily, so the fire performance of mineral-insulated cable is excellent.

The test shows that the mineral-insulated cable in the temperature up to 800 ℃ to 900 ℃ flames burned for 2h, and the cable has been able to normal operation.

In the 1000 ℃ flame burning for 30 min, the cable is still intact and continues to operate normally.

2 High-Temperature Operating Capacity

Mineral-insulated cables can be used at a normal temperature of 250 ℃.

In special cases, the cable can be close to the melting point of the copper sheath temperature, and a short period to maintain the work.

Very suitable for high-temperature places laying, such as metallurgy, boilers, glass kilns, blast furnaces, and other environments.

Its cross-sectional flow is also far more than other cables, because magnesium oxide powder has a better conductor coefficient than plastic, so at the same working temperature, the cross-sectional flow is greater.

For more than 16mm lines, you can reduce a cross-section, and for places where human contact is not allowed, you can reduce two cross-sections.

3 Waterproof and Explosion-Proof High Mechanical Strength

The insulation layer of mineral insulated cable is processed by a high-density compaction process and then protected by a seamless copper sheath layer, which must pass three requirements of fire resistance, spray resistance, and mechanical impact resistance in the product standard, and can withstand severe impact and mechanical damage.

Thus, it is not only protected from water, moisture, oil, and some chemical substances, but also suitable for use in places where there is a danger of explosion and for connecting various explosion-proof equipment and devices.

4 Overload Protection

When the line is overloaded, the plastic cable will cause insulation heating or breakdown due to overcurrent or overvoltage.

For mineral-insulated cables, as long as the heat does not reach the melting point temperature of copper, the cable will not be damaged.

Even if the instant breakdown, the high temperature of magnesium oxide at the breakdown point will not form carbide.

After the overload is cleared, the cable performance will not change and can continue to use normally.

5 Long Life Safety and Reliability

Because the structure of mineral insulated cable is composed of copper core and insulation sheath, is a closed whole, so the material is difficult to be the role of oxygen in the outside air and aging phenomenon, which makes the overall life of the cable length.

This, coupled with the copper sheath's characteristics, makes the cable better grounded, thus effectively achieving lightning protection grounding measures, thus ensuring the safe and reliable operation of electrical lines.

Due to the many excellent characteristics of mineral-insulated cables, they have been adopted by many electrical design codes or standards in recent years, and are also used in many projects in different industries.

Although mineral-insulated cables have strong performance, most people think that mineral-insulated cables are expensive and are not used.

This is not true, but through the continuous efforts of cable manufacturers and material suppliers in recent years, the price of mineral-insulated cables is approaching the price of ordinary cables.

ZMS cable also through the continuous introduction of advanced technology and equipment to improve the quality of mineral insulated cable at the same time with a more affordable price to promote this quality cable, I hope this cable in the future can be more widely spread to our lives, to help us to protect our life safety.