What is a flexible mineral insulated cable?

Flexible mineral insulated cables are mineral insulated cables made by twisting multiple copper cores. Flexible mineral insulated cable models include BTLY, YTTW, NG-A, BBTRZ, etc. Due to the wide variety of flexible mineral insulated cable models, more model specifications refer to the data of State Grid flexible mineral insulated cables, including cable model, cable outer diameter, rated current carrying capacity, cable cross-sectional area, cable weight, etc. Flexible mineral insulated cables are improved and upgraded models based on mineral insulated cable BTTZ. The selection of flexible mineral insulated cables must comply with the British BS 6387 standard for cables. The development of flexible mineral insulated cables inherits the excellent performance of BTTZ cables and makes installation and laying more convenient.

Flexible mineral insulated cable model YTTW BTTW BTLY BBTRZ and a brief introduction

1、 BBTRZ flexible mineral insulated cable fireproof cable

Ordinary wires and cables, due to the use of organic polymer materials for insulation, are prone to carbonization under flame conditions and lose their insulation effect. Due to the fact that the main material of flexible mineral insulated fire-resistant cables (BBTRZ) is composed of mineral compounds, it itself will not cause a fire and cannot burn or support combustion. And these materials generally have a high melting point above 1500 ℃, so fire-resistant cables can still function normally even under flame conditions, making them a true type of fire-resistant cable. And can pass the BS6387 C, W, and Z tests.

This type of cable can ensure emergency use after installation, and can also be used as a temperature resistant 125 ℃ halogen-free flame-retardant cable or fire-resistant cable in daily life. Due to its wide coverage, this series of cables not only overcomes the defects of rigid MI cables, but also leverages the advantages of flexible MI cables. It provides practical products for various key projects, enabling modern engineering to achieve the effect of short circuit non combustion and combustion non short circuit in electrical circuits, The application case used in this article demonstrates that flexible mineral insulated cables can be successfully applied not only in fire alarm and emergency rescue circuits, but also in high-density current and other special performance requirements.

2、 BTLY insulated (flexible) mineral insulated fire-resistant cable

Replacing copper tube drawing with aluminum as the main material not only simplifies the process and improves efficiency, but also significantly reduces product costs (aluminum only accounts for 1/10 of the comprehensive cost of copper). The reason why aluminum tubes can replace copper tubes and do not melt under high temperature flames is due to the expansion refractory layer extruded outside the aluminum tube: under the invasion of flames, the expansion layer foams and solidifies, forming a thick barrier to block the direct injection of flames on the aluminum tube. Not only is the integrity of the aluminum tube preserved, but also the heating temperature of the mica tape is reduced to below 600 ℃, undoubtedly improving the stability of the mica tape insulation (the insulation resistance of the mica tape increases with the decrease of temperature)

The fire resistance standard can pass the three assessments of BS6387: no breakdown under a flame at 950 ℃ for 3 hours, 15 minutes of water spray after 30 minutes at 650 ℃ (direct immersion is also acceptable), and 15 minutes of impact vibration without damage under a flame at 950 ℃, thus fully meeting the assessment standards of BTT in terms of fire resistance performance.

3、 BTTW (YTTW, BTTRZ, BTTE) flexible copper sheathed inorganic mineral insulated fire-resistant cable

The conductor of YTTW series metal sheathed inorganic mineral insulated power cables is made of multi stranded copper wire, and the insulation is mechanically wrapped with high-temperature resistant synthetic mica tape. The insulation layer is densely filled with alkali free glass fiber, and the sheath is longitudinally wrapped with copper tape and welded into copper tubes, which are then continuously rolled and corrugated. For specific requirements where the metal sheath cannot be exposed, a layer of polyolefin (low smoke and halogen-free) sheath can be added outside.

1. Cable conductor: It is made by twisting multiple copper wires and has good bending characteristics.

2. Insulation layer: Made of high-temperature resistant and non combustible inorganic mineral insulation material.

3. Copper sheath: Copper material, specially processed with good bending characteristics, and used as PE wire.

4、 BTTZ copper sheathed magnesium oxide mineral insulated cable

Fireproof and explosion-proof, waterproof, high-temperature, radiation resistant, electromagnetic interference resistant, high mechanical strength, good grounding performance, halogen-free, smoke-free, non-toxic, strong corrosion resistance, large current carrying capacity, strong overload capacity, small volume, light weight, and long service life

Fire resistance performance:

The cable not only cannot burn on its own, but also will not trigger a fire source. Even in the event of a fire, the cable can still function properly. And as long as the flame temperature is lower than the melting point temperature of copper, after the fire is eliminated, the cable does not need to be replaced and can still be used. Replacing the sheath and core wire material provides better fire resistance and can be used in oil and gas environments.