Mica Tape Mineral Insulated Corrugated Copper Sheath Flexible Fireproof Cable (RTTZ / YTTW Series)

Official national standard name: Mica Tape Mineral Insulated Corrugated Copper Sheath Cable with Rated Voltage up to 0.6/1kV, implemented in accordance with Chinese national standard GB/T 34926-2017. Main models include RTTZ, YTTW and RTTYZ. It is a flexible mineral insulated fire-resistant cable, which thoroughly improves the defects of traditional rigid magnesium oxide mineral cables (BTTZ), such as poor bendability, complicated installation, moisture susceptibility and cumbersome connectors. Adopting multi-layer high-temperature resistant mica tape as inorganic insulation core and corrugated rolled copper sheath structure, it combines ultra-stable fire resistance and flexible laying performance, serving as the premium preferred fire-resistant cable for Class 1 fire loads.

1. Four-Layer Standard Cable Structure

1. Stranded Oxygen-Free Copper ConductorClass 2 stranded high-purity oxygen-free copper conductor features low power loss and low heat generation. The stranded design delivers natural flexibility, different from solid single-core rigid conductors of traditional mineral cables, suitable for curved wiring layout.

2. Mica Tape Mineral Fire-Resistant Insulation Layer (Core Fire Barrier)Continuous wrapping of multi-layer high-temperature synthetic mica tape forms an inorganic insulation system, with temperature resistance exceeding 1000℃. It will not melt or carbonize under open flame. Compact glass fiber filling isolates air to prevent insulation breakdown, acting as the core guarantee for continuous power supply during fires.

3. Corrugated Rolled Copper SheathManufactured by longitudinally argon-arc welding copper strip into a copper tube followed by continuous corrugation rolling:

• The corrugated structure greatly enhances flexibility, with bending radius ranging from 6 to 20 times the cable outer diameter, easily routing around cable tray bends and shaft corners;

• Integrated sealed copper sheath blocks moisture infiltration completely, eliminating the hidden danger of electric leakage caused by dampness in old rigid mineral cables;

• It can be directly used as protective earth conductor (PE line) without additional grounding wire;

• Provides integrated electromagnetic shielding, impact resistance, compression resistance and corrosion protection.

4. Optional Low Smoke Zero Halogen (LSZH) Polyolefin Outer SheathLSZH sheath can be equipped for underground humid areas, outdoor sites and acid-alkali corrosive environments to further boost weather resistance, anti-corrosion and scratch resistance; bare copper sheath laying is acceptable for dry indoor fire shafts.

2. Core Performance Advantages

1. Top-Tier Fire Resistance, Passing 3 Strict BS 6387 Fire TestsFully complies with three rigorous fire resistance standards of British BS 6387 specification:

• Item C: Continuous power supply without breakdown under 950℃ flame for 3 hours;

• Item W: Stable energization after 30 minutes of 650℃ flame combustion plus 15 minutes of water spray;

• Item Z: Normal operation under 950℃ flame accompanied by mechanical vibration & impact for 15 minutes; It ensures uninterrupted power supply for fire-fighting equipment under severe fire conditions, outperforming ordinary flame-retardant cables and Class B1 fire-resistant cables.

2. Zero Halogen, Low Smoke & Non-Toxic, Eco-Friendly SafetyEntire inorganic insulation system contains no halogen or PVC plastics. No toxic hydrogen halide gas is released during combustion with extremely low smoke emission. It maintains clear visibility for evacuation, reduces suffocation & poisoning risks for occupants, and avoids corrosion to building steel structures and precision electrical equipment.

3. Flexible Installation & High Construction EfficiencyNo customized elbows or numerous intermediate joints required unlike rigid BTTZ cables. Single continuous production length can reach over 1000 meters to cut joint failure points drastically. It adapts to conduit pulling, cable tray laying, trench burial, vertical shaft and tunnel wiring, effectively lowering labor cost and construction period.

4. Moistureproof, Waterproof & Ultra-Long Service LifeSealed corrugated copper sheath fully blocks water vapor and underground water penetration, enabling stable long-term operation in utility tunnels, damp basements and water-adjacent machine rooms. Inorganic mineral insulation never ages, with a designed service life exceeding 100 years under normal operating conditions, far longer than the 30-year lifespan of rubber & plastic cables.

5. Stable Electrical Performance & Sufficient Current-Carrying CapacityMaximum continuous operating temperature: 90℃; instantaneous short-circuit withstand temperature: 250℃. It boasts excellent insulation resistance and low power transmission loss. The integral copper sheath realizes full electromagnetic shielding, free from external signal interference and will not disturb weak-current & signal cables, ideal for data centers and rail transit power supply.

6. Comprehensive Environmental AdaptabilityExcellent compression resistance, impact resistance and rodent/termite proof performance; resistant to acid-alkali soil, UV radiation and humidity heat; applicable for overhead outdoor laying, direct burial, river-crossing installation; qualified for explosion-proof scenarios in chemical, metallurgical high-temperature & hazardous industrial plants.

3. Model Classification

• RTTZ / YTTW (Bare corrugated copper sheath): General type for dry indoor fire shafts, machine rooms and building emergency circuits

• RTTYZ / YTTWV (With LSZH outer sheath): Special type for damp basements, utility tunnels, outdoor and corrosive environments

4. Application Scenarios

Mandatorily adopted for Class 1 fire loads and highest fire safety requirement venues: Metro & light rail transit, airport terminals, large tertiary hospitals, super high-rise residential & commercial complexes, exhibition centers, stadiums, data centers and financial computer rooms; Also widely deployed in underground utility tunnels, civil air defense projects, chemical parks, metallurgical steel plants, nuclear power supporting facilities and tunnel fire protection systems; Specially applied for critical emergency power circuits including fire water pumps, smoke exhaust fans, fire elevators, emergency evacuation lighting and fire alarm control systems.