IEC Standard XLPE Insulated Fire-Resistant Low Voltage Power Cable

Core Standards System
This product series strictly complies with the following international and national standards:
- Design standard: IEC 60502-1 (Power cables with extruded insulation and their accessories for rated voltages of 1 kV and 3 kV).
- Fire resistance: IEC 60331 series (Test for circuit integrity under fire conditions), requiring that the circuit remains intact under a flame of not less than 750 °C for 90 minutes.
- Conductor standard: IEC 60228 (Conductors of insulated cables).
- Flame retardant characteristics: IEC 60332 series (Vertical flame test for a single cable and for bunched cables).
- Low-smoke zero-halogen indicators (for LSZH types): IEC 60754 (Determination of corrosive gas emission) and IEC 61034 (Measurement of smoke density).

Model Code Definitions
The product typically uses international or national industry codes for identification:
1. Common international examples:
   - N2XH FE 180: Copper conductor / XLPE insulation / halogen-free low-smoke flame retardant and fire-resistant (circuit continuity maintained for 180 minutes).
   - CU/MICA/XLPE/PVC: Copper conductor / mica tape fire barrier / XLPE insulation / PVC sheath.
2. Common Chinese codes:
   - WDZN-YJY: Halogen-free low-smoke flame retardant and fire-resistant, XLPE insulated, polyolefin sheathed.
   - NH-YJV: Copper conductor, XLPE insulated, PVC sheathed, fire-resistant power cable.
   - A/B/C: Denotes fire resistance or flame retardant class.

Product Specification Range
The conductor may be annealed copper or aluminium, satisfying various cross-section requirements from residential buildings to large industrial power distribution:
- Core configurations: 1, 2, 3, 4, 5 cores, and combinations such as 3+1, 3+2, 4+1.
- Cross-section range: 1.5 – 1000 mm² (single-core up to 1000 mm², multi-core typically up to 400 mm²).

Core Technical Parameters
1. Rated voltage (U₀/U): 0.6/1 kV (maximum system voltage 1.2 kV).
2. Operating temperature: The maximum continuous permissible conductor operating temperature is 90 °C; during a short circuit (max. 5 s), the maximum conductor temperature can reach 250 °C.
3. Fire resistance performance:
   - Class A: Flame temperature 950–1000 °C, fire exposure for not less than 90 minutes.
   - Class B: Flame temperature 750–800 °C, fire exposure for not less than 90 minutes.
4. Minimum bending radius:
   - Non-armoured type: ≥ 6D (D is the overall cable diameter).
   - Armoured type: ≥ 12D.

Cable Structural Characteristics
- High-quality conductor: Annealed copper conforming to IEC 60228 ensures sound electrical conductivity.
- Fire-resistant barrier (core component): Multiple layers of mica tape are lapped around the conductor. Mica withstands temperatures above 1000 °C and is the core barrier ensuring power supply integrity during a fire.
- High-performance insulation: XLPE material forms a network structure through a cross-linking process, offering dielectric strength and heat resistance far superior to standard PVC.
- Specialized outer sheath:
  - Flame retardant PVC: Suitable for general indoor and tunnel applications, with good corrosion resistance.
  - LSZH (low-smoke zero-halogen): Light transmittance during combustion ≥ 60%, no release of highly toxic halogen acid gases (pH ≥ 4.3), particularly suitable for densely populated places.

Applicable Scenarios
- Enclosed densely populated places: Subways, railway stations, airport terminals, hospitals, schools, large shopping malls, and super high-rise buildings.
- Fire interlock systems: Specifically used for fire pump power supply cables, emergency lighting, smoke exhaust fans, fire alarm and public address systems.
- Critical energy facilities: Nuclear power plants (outside the nuclear island), thermal power plants, large data centers, and petrochemical facility areas.

Selection and Installation Recommendations
- Rating matching: For important fire protection equipment, priority should be given to products meeting Class A fire resistance (950 °C class) with Class ZA flame retardant performance.
- Environmental safety: In enclosed spaces, WDZN (halogen-free low-smoke) series must be selected to prevent secondary harm to personnel from toxic smoke generated by halogen-containing materials.
- Armour selection: For direct underground burial or environments with risk of external mechanical damage, it is recommended to select steel tape armour (such as YJY22 or STA) to enhance mechanical protection.
- Installation temperature: The ambient temperature during installation should not be lower than 0 °C; otherwise, the cable needs to be preheated.