Flexible mineral insulated cables are mineral insulated cables made of twisted copper cores. The types of flexible mineral insulated cables are: BTLY, YTTW, NG-A, BBTRZ, etc. Due to the variety and models of flexible mineral insulated cables, more models and specifications refer to the data of flexible mineral insulated cables of the State Grid, including cable model, cable outer diameter, rated Ampacity, cable cross-sectional area, cable weight, etc. The flexible mineral insulated cable is an improved and upgraded model based on the mineral insulated cable BTTZ. The selection of flexible mineral insulated cables must pass the British bs6387 standard cables. The research and development of flexible mineral insulated cables has inherited the excellent performance of BTTZ cables, and it is more convenient to install and lay.

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

1. BBTRZ flexible mineral insulated cable fireproof cable

General wires and cables use organic polymer materials for insulation, so they are easily carbonized under flame conditions and lose their insulating effect. Since the main material of the flexible mineral insulated fireproof cable (BBTRZ) is composed of mineral compounds, it will not cause fire by itself, and it is impossible to burn or support combustion. These materials generally have a higher melting point above 1500°C, so the fireproof cable can also perform normal power transmission functions even under flame conditions, and it is a real fireproof cable. And can pass BS6387 C, W, Z test.

This type of cable can guarantee emergency use after installation, and can also be used as a temperature-resistant 125°C halogen-free flame-retardant cable and fire-resistant cable. Because this series of cables covers a wide range, it not only overcomes the defects of rigid MI cables, but also gives full play to flexible MI cables. The advantages of cables, and provide practical products for various key projects, so that modern engineering can achieve the effect of short circuit without burning, burning without short circuit. The application cases used in this paper prove that flexible mineral insulated cables are not only used in fire alarm and emergency rescue It can be successfully applied in the fire protection performance of the circuit, and can also be popularized and applied in the case of high-density current and other special performance requirements.

2. BTLY isolated (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 greatly reduces the product cost (aluminum is only 1/10 of the comprehensive cost of copper). The reason why the aluminum tube can replace the copper tube is that it does not melt under high-temperature flames, thanks to the expansion refractory layer extruded on the outside of the aluminum tube: the expansion layer foams and solidifies under the attack of the flame, forming a thick barrier that blocks the impact of the flame on the aluminum tube. Tube for direct injection. Not only the integrity of the aluminum tube is preserved, but also the heating temperature of the mica tape is reduced to below 600°C, and the insulation stability of the mica tape is undoubtedly improved (the insulation resistance of the mica tape increases with the decrease of temperature)

The fire-resistant standard can pass the three assessments of BS6387: that is, it will not break down under the flame of 950°C for 3 hours, withstand water spraying for 15 minutes after 30 minutes at 650°C (directly immersed in water), and withstand knocking and vibration for 15 minutes under the flame of 950°C without damage. In terms of fire resistance, it can fully meet the assessment standard of BTT.

3. BTTW (YTTW, BTTRZ, BTTE) flexible copper sheath inorganic mineral insulated fireproof cable

The conductor of YTTW series metal sheathed inorganic mineral insulated power cable is made of multi-strand copper stranded wire, the insulation is mechanically wrapped with high temperature resistant synthetic mica tape, the insulation layer is densely filled with non-alkali glass fiber, and the sheath is welded longitudinally with copper tape It is formed into a copper tube, and then formed by continuous rolling and corrugation. If the metal sheath is not exposed to specific requirements, a layer of polyolefin (low-smoke and halogen-free) sheath can be added outside.

1. Cable conductor: twisted with multiple strands of copper wire, it has good bending properties.

2. Insulation layer: High temperature resistant, non-combustible inorganic mineral insulation material.

3. Copper sheath: Copper material, which has good bending properties after special processing, and is used as PE wire.

4. BTTZ copper sheathed magnesium oxide mineral insulated cable

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

Fire resistance:

Not only can the cable itself not burn, but it will not cause an ignition source. Even in the event of a fire, the cable will still work. And as long as the flame temperature is lower than the melting point of copper, after the fire is eliminated, the cable can continue to be used without replacement. The replacement sheath and core wire materials are more fire resistant and can be used in oil and gas environments.