What is a flexible mineral insulated cable?

Flexible mineral insulated cable is a mineral insulated cable 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 Cable, including cable model, cable outer diameter, rated current carrying capacity, cable cross-sectional area, cable weight, etc. Flexible mineral insulated cable is an improved and upgraded model based on mineral insulated cable BTTZ. The selection of flexible mineral insulated cables must comply with the British BS6387 standard. 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 brief introduction

1、 BBTRZ flexible mineral insulated fire-resistant cable

Due to the use of organic polymer materials for insulation, general wires and cables are prone to carbonization and loss of insulation under flame conditions. Due to the fact that the main material of flexible mineral insulated fire-resistant cable (BBTRZ) is composed of mineral compounds, it itself does not cause fires and cannot burn or support combustion. And these materials generally have a high melting point above 1500 ℃, so fire-resistant cables can still perform normal power transmission functions even under flame conditions, making them a truly fire-resistant cable. And it can pass the BS6387 C, W, 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. 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, and provides practical products for key projects, achieving the effect of short circuit non combustion and combustion non short circuit in electrical circuits. The application cases used in this article prove that flexible mineral insulated cables can not only be successfully applied in fire alarm and emergency rescue circuits, but also be promoted and applied in high-density current and other special performance requirements.

2、 BTLY Insulated (Flexible) Mineral Insulated Cable Fireproof Cable

Using aluminum as the main material for metal tube extrusion instead of copper tube drawing not only simplifies the process and improves efficiency, but also significantly reduces product costs (aluminum is only 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 on the outside of the aluminum tube: under the invasion of flames, the expansion layer foams and solidifies, forming a thick barrier to block the direct spray of flames on the aluminum tube. Not only is the integrity of the aluminum tube preserved, but the heating temperature of the mica tape is also reduced to below 600 ℃, undoubtedly improving the stability of the mica tape insulation (the insulation resistance of the mica tape increases with decreasing temperature)

The fire resistance standard can pass the three assessments of BS6387: no breakdown under a flame of 950 ℃ for 3 hours, 15 minutes of water spray after being immersed in water at 650 ℃ for 30 minutes (direct immersion is also acceptable), and 15 minutes of impact vibration under a flame of 950 ℃ without damage, thus fully meeting the BTT assessment standard 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 tube, which is then continuously rolled and corrugated. In specific situations where the metal sheath cannot be exposed, a layer of polyolefin (low smoke halogen-free) sheath can be added on the outside.

1. Cable conductor: It is made up of multiple stranded copper wires and has good bending characteristics.

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

3. Copper sheath: Made of copper material with excellent bending characteristics after special processing, and used as a PE wire.

4、 BTTZ copper sheathed magnesium oxide mineral insulated cable

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

Fire resistance performance:

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