BBTRZ cable, with the full name of flexible magnesium hydroxide mineral-insulated non-combustible fireproof cable, is a high-performance mineral-insulated cable mainly composed of inorganic materials, widely used in locations with extremely high requirements for power supply safety. On the basis of inheriting the advantages of traditional rigid mineral cables such as fire resistance, explosion protection, and high-temperature resistance, it significantly improves flexibility and installation convenience, and is known as a "truly fireproof cable."
I. Core Structural Composition
BBTRZ cable adopts a multi-layer composite structure design to ensure its stable operation in extreme environments:
Conductor: Stranded from multiple oxygen-free copper wires, featuring good electrical conductivity and bending characteristics.
Insulation layer: Wrapped with high-temperature-resistant mica tape, capable of withstanding temperatures above 950°C while maintaining insulation performance without degradation.
Mineral filler layer: Flexible mineral mixture (such as magnesium hydroxide) is used to fill the gaps between wire cores, providing thermal insulation, fire protection, and moisture resistance.
Waterproof isolation layer: Polyethylene material, enhancing the overall sealing performance of the cable.
Outer sheath: Low-smoke halogen-free polyolefin material, featuring flame retardancy, non-toxicity, and corrosion resistance, suitable for use in densely populated areas.
Compared with rigid mineral cables such as BTTRZ, BBTRZ has no metal tube sheath, but instead adopts a double sheath structure (copper tape longitudinal wrapping + PVC/steel tape armoring), making it softer and easier to bend, with no special tools required for installation.
II. Key Performance Advantages
Excellent Fire Resistance
It can maintain power supply continuously for 180 minutes (3 hours) in a 950°C flame without breakdown, meeting the requirements of the GB/T 19216 standard.
It also has resistance to water spray and mechanical impact, and can still ensure the normal operation of firefighting equipment during a fire.
High Flexibility and Installation Convenience
Small bending radius, generally 6–12 times the cable outer diameter, facilitating installation in narrow spaces or complex routes.
Supports fixed-length production without intermediate joints, reducing the risk of failure; ordinary electricians can install it in the conventional manner.
Safety and Environmental Friendliness
No toxic gases are released during combustion, with low smoke density and high light transmittance, facilitating personnel evacuation and firefighting rescue.
Halogen-free, lead-free, and no corrosive gas emissions, meeting modern green building standards.
Excellent Electrical and Mechanical Performance
Large current-carrying capacity, superior to ordinary flame-retardant cables at the same cross-section, allowing selection of 1–2 cross-section grades lower.
Voltage withstand rating up to 1000V, strong impulse voltage resistance, suitable for systems with frequent start-stop or large load fluctuations.
Certain shielding effect, capable of resisting electromagnetic interference, suitable for sensitive environments such as data centers and hospitals.
III. Typical Application Scenarios
BBTRZ cable is particularly suitable for critical circuits that must maintain continuous power supply during a fire, commonly found in the following locations:
High-rise buildings: Power supply circuits for fire pumps, emergency lighting, smoke control and exhaust systems, fire elevators, etc.
Public facilities: Power and control circuits in densely populated areas such as hospitals, schools, gymnasiums, exhibition centers, and rail transit.
Industrial and energy sectors: Power distribution systems in high-temperature and high-risk environments such as petrochemical plants, power stations, and substations.
Underground works: Power transmission in humid and enclosed spaces such as tunnels, underground garages, and cable trenches.
