Let me share with you a brief introduction to the flexible mineral insulated cable models YTTW, BTTW, BTLY, and BBTRZ.
1. BBTRZ Flexible Mineral Insulated Cable: Fire-Resistant Cable
General wires and cables are made of organic polymer materials for insulation, which easily carbonizes under flames, losing their insulating properties. Flexible mineral insulated fire-resistant cable (BBTRZ) is primarily composed of mineral compounds, which are inherently non-flammable and cannot burn or support combustion. These materials generally have high melting points exceeding 1500°C, making them truly fire-resistant, capable of transmitting power even under flames. They can also pass BS6387 C, W, and Z tests.
After installation, this type of cable can be used for emergency situations and can also be used as a 125°C halogen-free flame-retardant or fire-resistant cable. Due to its wide coverage, this cable series overcomes the shortcomings of rigid MI cables while leveraging the advantages of flexible MI cables. It provides practical products for key projects, enabling modern engineering to achieve the goal of preventing short circuits from burning and burning from short circuits in electrical wiring. The application case presented in this article demonstrates the successful application of flexible mineral insulated cables not only in fire-resistant applications such as fire alarms and emergency lifeline circuits, but also in high-density current and other applications requiring specialized performance.
II. BTLY Isolated (Flexible) Mineral Insulated Cable, Fire-Resistant Cable
Using aluminum as the primary metal tube extrusion material instead of copper tube drawing not only simplifies the process and improves efficiency, but also significantly reduces product costs (aluminum costs only 1/10 of the overall cost of copper). The reason aluminum tubes can replace copper tubes and remain resistant to high-temperature flames is due to the intumescent refractory layer extruded over the tubes. Under the attack of flames, the intumescent layer foams and solidifies, forming a thick barrier that blocks the flames from directly impacting the tubes. This not only preserves the integrity of the tubes but also reduces the heating temperature of the mica tape to below 600°C, significantly improving the insulation stability of the mica tape (the insulation resistance of mica tape increases with decreasing temperature).
The fire resistance standard meets the three BS6387 tests: no breakdown under a 950°C flame for 3 hours; no damage after 30 minutes at 650°C and then 15 minutes of water spray (direct immersion is also acceptable); and no damage after 15 minutes of impact and vibration at 950°C, thus fully meeting the BTT fire resistance standards.
3. BTTW (YTTW, BTTRZ, BTTE) Flexible Copper Sheathed Inorganic Mineral Insulated Fire-Resistant Cables
The YTTW series metal-sheathed inorganic mineral insulated power cables feature multi-strand copper conductors, mechanically wrapped with high-temperature-resistant synthetic mica tape, and densely packed with alkali-free glass fiber. The sheath is longitudinally wrapped with copper tape, welded into a copper tube, and then continuously corrugated. For applications where the metal sheath cannot be exposed, a polyolefin (low-smoke, zero-halogen) sheath can be added.
1. Cable Conductor: Made of twisted copper wires with excellent bending properties.
2. Insulation: Made of high-temperature-resistant, non-flammable inorganic mineral insulation material.
3. Copper Sheath: Made of copper, specially processed for excellent bending properties, and also functions as a PE conductor.
4. Outer Sheath: Made of a low-smoke, non-toxic plastic material with excellent corrosion resistance.
IV. BTTZ Copper-Sheathed Magnesium Oxide Mineral Insulated Cable
Fireproof, explosion-proof, waterproof, high-temperature resistant, radiation-resistant, electromagnetic interference-resistant, high mechanical strength, excellent grounding performance, halogen-free, smokeless, non-toxic, corrosion-resistant, high current carrying capacity, strong overload capacity, compact size, light weight, and long life.
Fire Resistance:
The cable itself is incombustible and will not ignite. Even in the event of a fire, the cable will continue to operate normally. Furthermore, as long as the flame temperature is below the melting point of copper, the cable can continue to be used after the fire is extinguished without replacement. Replacing the sheath and core materials improves fire resistance and allows use in oil and gas environments.
