Rated Voltage 6–35kV XLPE Insulated Fire-Resistant Power Cable

Executive Standards
This series strictly complies with the following national, industry, and enterprise-specific standards:
- Q/320481SS295-2022: Fire-resistant power cables with XLPE insulation for rated voltages from 6 kV to 35 kV (core specialized standard).
- GB/T 12706.2 / .3-2020: Specifies the basic construction and performance of extruded insulation power cables for voltages from 6 kV to 35 kV.
- GB/T 19666-2019: General rules for flame retardant and fire-resistant wires and cables or optical cables, defining fire resistance classifications and codes.
- GB/T 19216 (IEC 60331): Test standard for circuit integrity under fire conditions.

Model Code Definitions
Model codes combine specific designations to reflect insulation material, fire resistance, and environmental characteristics:
- N / NH: Fire-resistant code (ensuring circuit integrity).
- YJ: Cross-linked polyethylene (XLPE) insulation.
- V / Y: Outer sheath material (V-PVC; Y-PE or polyolefin).
- WDZN: Low-smoke zero-halogen (LSZH) flame retardant and fire-resistant type.
- Z(A/B/C)N: Flame retardant (Class A/B/C) + fire-resistant.
- 62 / 63 / 22 / 33: Armoring structures (e.g., double non-magnetic metal tape, steel tape, or steel wire armor).

Example models:
- WDZAN-YJY: Copper core, XLPE insulated, polyolefin sheathed, LSZH flame retardant Class A fire-resistant power cable.
- NH-YJV22: Copper core, XLPE insulated, steel tape armored, PVC sheathed fire-resistant power cable.

Product Specification Range
The cables cover single-core and three-core configurations to meet capacity requirements at different voltage levels:
- 3.6/6 kV Grade:
  · Single-core: 10 – 1000 mm²
  · Three-core: 10 – 500 mm²
- 6/6 kV, 6/10 kV Grade:
  · Single-core: 16 – 1000 mm²
  · Three-core: 16 – 500 mm²
- 8.7/10 kV, 8.7/15 kV Grade:
  · Single-core: 25 – 1000 mm²
  · Three-core: 25 – 500 mm²
- 12/20 kV to 26/35 kV: Large cross-section fire-resistant specifications available upon request.

Core Technical Parameters
1. Conductor Operating Temperature: The maximum allowable long-term operating temperature is 90°C; the maximum temperature during a short circuit (up to 5 s) is 250°C.

2. Fire Resistance Performance:
- Class A fire resistance (highest level): Capable of maintaining power supply for 90 minutes (or longer by agreement) under 950°C–1000°C flame conditions without circuit interruption.
- Class B fire resistance: Capable of maintaining power supply for 90 minutes under 750°C–800°C flame conditions.

3. Electrical Performance: Extremely low partial discharge (≤5 pC at 1.73 U₀); insulation resistance constant (at 90°C) ≥3.67 MΩ·km.

4. Environmental Characteristics: For low-smoke zero-halogen (WDZN) types, light transmittance during combustion ≥60%, pH value ≥4.3, with extremely low corrosivity.

Structural Characteristics
- Triple-layer co-extrusion shielding: The conductor shield, XLPE insulation, and insulation shield are applied using a triple co-extrusion process, ensuring a uniform electric field and eliminating partial discharge risks.
- Core fire-resistant layer: Multiple layers of high-quality synthetic mica tape are lapped around the conductor. Mica tape has an extremely high melting point and dielectric strength, providing a critical barrier to prevent phase-to-phase short circuits during a fire.
- Metallic shielding and grounding: Copper tape or copper wire shielding structures provide high fault current carrying capacity.
- Comprehensive protective sheath: The outer sheath can be selected from flame retardant PVC, weather-resistant PE, or low-smoke zero-halogen polyolefin based on the installation environment, with optional armoring to resist mechanical stress.

Applicable Scenarios
- Major transportation hubs: Subway tunnels, airport terminals, high-speed rail stations, and cross-sea tunnels.
- Densely populated and high-risk areas: Large shopping malls, hospitals, schools, theaters, and petrochemical control zones.
- Critical energy facilities: Power plant step-up substations, key substation outgoing lines, and distribution mains in non-containment areas of nuclear power plants.
- Emergency support systems: Specifically designed to supply medium-voltage power to fire pumps, smoke exhaust fans, emergency lighting, and fire alarm systems.

Selection and Installation Recommendations
- Fire resistance rating matching: For public or super high-rise buildings exceeding 100 meters in height, it is recommended to prioritize cables that meet Class A fire resistance standards and possess Class ZA flame retardant performance, such as the WDZAN series.
- Installation temperature limit: The ambient temperature during installation should not be lower than 0°C. In extremely cold environments, preheat the cable to prevent damage to the fire-resistant barrier.
- Bending radius control: Due to the fire-resistant barrier, strictly observe minimum bending radius requirements during installation (typically 20D for single-core and 15D for three-core cables, where D is the cable diameter) to avoid damaging the internal mica tape structure through rough handling.