Mineral-Filled Flexible Specialty Fire-Resistant Cable (BBTRZ)

Executive Standards
This product is developed and manufactured in strict accordance with stringent enterprise technical standards:
- Q/320481SS461-2024: Dedicated execution standard for mineral-filled flexible specialty fire-resistant cables.
- It also conforms to the general technical requirements for flame retardant and fire-resistant characteristics in GB/T 19666.

Model Code Definitions
- B: Cable for building wiring (also interpreted by some as a fire-resistant code).
- B: Insulation is mineral compound.
- T: Conductor material is copper (T is usually omitted).
- R: Flexible construction.
- Z: Heavy-duty or specialty code.
- BBTRZ: The full designation refers to mineral-filled flexible magnesium hydroxide fire-resistant cable.

Product Specification Range
The conductor uses high-quality annealed copper, with specifications covering single-core to multi-core and combination configurations to meet various current-carrying requirements:
- 1 core: 1.5 – 630 mm²
- 2 cores: 1.5 – 240 mm²
- 3 cores: 1.5 – 240 mm²
- 4 cores: 1.5 – 240 mm²
- 5 cores: 1.5 – 185 mm²
- Combination configurations:
  - (3×2.5+1×1.5) to (3×240+1×120) mm²
  - (3×2.5+2×1.5) to (3×240+2×120) mm²
  - (4×2.5+1×1.5) to (4×240+1×120) mm²

Core Technical Parameters
1. Rated voltage (U₀/U): 0.6/1 kV.
2. Fire resistance performance: Capable of maintaining circuit continuity for an extended duration under a flame at 950 °C – 1000 °C, meeting Class A fire resistance test requirements.
3. Operating temperature: The maximum continuous permissible conductor operating temperature is generally 90 °C; under emergency fire conditions, the cable can withstand higher instantaneous temperature rises.
4. Bending radius: Due to the flexible design, the bending radius is much smaller than that of rigid mineral insulated cables, making installation more convenient.
5. Electrical performance: The finished cable must pass a power-frequency AC voltage test to ensure that insulation strength does not fail under high-temperature conditions.

Cable Structural Characteristics
- Conductor: Stranded fine copper wires, providing sound electrical conductivity and flexibility.
- Insulation layer: High-temperature-resistant, high-performance synthetic material, combined with a mineral fire-resistant tape.
- Filling layer: The core fire-resistant layer, filled with mineral compounds (such as magnesium hydroxide). When heated, it releases crystallized water to absorb heat and forms a ceramic-hard barrier.
- Sheath layer: The outer layer uses a low-smoke zero-halogen flame retardant polyolefin sheath that is moisture-resistant, corrosion-resistant, and ageing-resistant.

Applicable Scenarios
- Super high-rise buildings: Distribution mains for commercial centers, office buildings, and residential towers.
- Public facilities: Hospitals, schools, theatres, large sports venues, and other densely populated places.
- Transportation hubs: Subway tunnels, airport terminals, underground utility tunnels, and car parks.
- Industrial safety: Control and power circuits in petrochemical, metallurgical, and other industries with very high fire protection requirements.
- Fire protection systems: Dedicated to fire-fighting lifts, fire extinguishing systems, and emergency evacuation command transmission.

Product Advantages and Selection Recommendations
- Installation advantage: BBTRZ is supplied in coils with unlimited lengths, requiring no intermediate joints, which reduces leakage risk and installation costs.
- Environmental safety: Halogen-free, low smoke, and non-toxic. The smoke produced during a fire has high light transmittance, facilitating personnel evacuation.
- Durability: Not only fire-resistant, but also offers good resistance to mechanical impact, water, and rodent/ant damage.
- Selection tip: When selecting for special-grade or first-grade buildings, priority should be given to B1 class flame retardant ratings (e.g., WDZB1N-BBTRZ) to comply with the latest building fire protection codes.