IEC Standard XLPE Insulated Low-Smoke Zero-Halogen Flame Retardant Low Voltage Power Cable

Executive Standards
This product is designed, manufactured, and tested in accordance with the following international and national standards:

- IEC 60502-1: Power cables with extruded insulation and their accessories for rated voltages from 1 kV up to 30 kV – Part 1: Cables for rated voltages of 1 kV and 3 kMain technical requirements for cable construction, electrical performance, mechanical properties, etc.
- IEC 60228: Conductors of insulated cables. Conductor material and cross-sectional area requirements.
- IEC 60332-1-2: Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test for vertical flame propagation for a single insulated wire or cable. Single cable flame retardant test.
- IEC 60332-3-24: Tests on electric and optical fibre cables under fire conditions – Part 3-24: Test for vertical flame spread of vertically-mounted bunched wires or cables – Category C. Bunched cable flame retardant test.
- IEC 60754-1: Test on gases evolved during combustion of materials from cables – Part 1: Determination of halogen acid gas content. Halogen-free performance test.
- IEC 60754-2: Test on gases evolved during combustion of materials from cables – Part 2: Determination of acidity (by pH measurement) and conductivity. Combustion gas corrosivity test.
- IEC 61034-2: Measurement of smoke density of cables burning under defined conditions – Part 2: Test procedure and requirements. Smoke density measurement.
- GB/T 12706.1: Extruded insulation power cables and accessories for rated voltages from 1 kV up to 35 kV – Part 1: Cables for rated voltages of 1 kV and 3 k(National adoption of IEC 60502-1).
- GB/T 19666: General rules for flame retardant and fire-resistant wires and cables. Flame retardant classification.

Through testing according to the above IEC series standards, the product is ensured to have safety characteristics such as inhibiting fire spread, producing very low smoke, releasing no toxic halogen gases, and emitting combustion gases with low corrosivity during a fire.

Type Designation
Taking the standard type WDZ-YJY-0.6/1 kV as an example, the meaning of each letter is as follows:

- W: Halogen Free – The cable material does not contain halogen elements (e.g., chlorine, fluorine, bromine), so no toxic hydrogen halide gases are produced during combustion.
- D: Low Smoke – The smoke concentration generated during cable combustion is very low, ensuring visibility for evacuation.
- Z: Flame Retardant – The cable possesses the property of inhibiting flame spread.
- ZA/ZB/ZC: Flame Retardant Class – Class A, Class B, Class C, from high to low.
- YJ: XLPE Insulation – The insulating material is cross-linked polyethylene, chemically or physically cross-linked.
- Y: Polyolefin Sheath – The sheathing material is low-smoke zero-halogen flame retardant polyolefin.
- N: Fire Resistant – Additional fire resistance property, suitable for applications with higher fire resistance rating requirements.
- YJLY: Aluminium conductor version – Conductor material is aluminium.

Cable Construction
From inside to outside, the cable consists of:

1. Conductor: Uses Class 1 (solid) or Class 2 (stranded) annealed copper conductor, complying with IEC 60228 requirements. The conductor surface is smooth, free of oil and burrs, and has good electrical conductivity and mechanical strength. The aluminium version uses an aluminium conductor.
2. Insulation: Cross-linked polyethylene (XLPE) material. Through chemical or physical cross-linking, the polyethylene molecular structure changes from a chain-like to a three-dimensional network, significantly raising the temperature rating. The insulation thickness varies depending on conductor cross-sectional area, with a minimum insulation thickness generally between 0.7 and 1.8 mm.
3. Fillers (multi-core cables): Low-smoke zero-halogen flame retardant filling materials, such as high-temperature flame retardant filler ropes, used to make the cable round and enhance overall flame retardant performance.
4. Inner covering/binding tape (optional): Low-smoke zero-halogen flame retardant tape or halogen-free flame retardant inner covering, enhancing the fire barrier effect.
5. Armour layer (armoured types such as WDZ-YJY23): Steel tape armour or tinned copper wire braided armour, providing mechanical protection.
6. Outer sheath: Low-smoke zero-halogen flame retardant polyolefin (LSZH) material, free of halogen elements. It produces very little smoke and releases no corrosive or toxic gases during combustion. The sheath is typically black in colour, with customization available based on customer requirements.

Main Technical Parameters

5.1 Electrical Parameters
- Rated voltage (U₀/U): 0.6/1 kV
- Maximum system voltage (Um): 1.2 kV
- Power-frequency voltage withstand test: 3.5 kV / 5 min, no insulation breakdown
- Conductor resistance: Meets IEC 60228 / GB/T 3956 requirements

5.2 Temperature Parameters
- Maximum continuous conductor operating temperature: +90 °C
- Permissible conductor short-circuit temperature (max. 5 s): +250 °C
- Maximum permissible overload temperature: +130 °C
- Ambient temperature range: -25 °C to +45 °C
- Minimum installation temperature: 0 °C (preheat the cable if ambient temperature is below 0 °C)

5.3 Bending Radius
- Single-core cable (non-armoured): 20 times the cable outer diameter (20D)
- Multi-core cable (non-armoured): 15 times the cable outer diameter (15D)
- Single-core cable (armoured): 15 times the cable outer diameter (15D)
- Multi-core cable (armoured): 12 times the cable outer diameter (12D)
Note: D is the actual outer diameter of the cable.

5.4 Specification Range
Core Configuration – Conductor Cross-Sectional Area Range:
1 core: 1.5 – 1000 mm² (copper) / 16 – 630 mm² (aluminium)
2 cores: 1.5 – 400 mm²
3 cores: 1.5 – 400 mm²
4 cores: 1.5 – 400 mm²
5 cores: 1.5 – 400 mm²
3+1 cores: 2.5 – 400 mm²
3+2 cores: 2.5 – 400 mm²
4+1 cores: 2.5 – 400 mm²

5.5 Core Identification (Copper)
2 cores: Red, Blue
3 cores: Yellow, Green, Red; or Red, Blue, Yellow/Green
4 cores: Yellow, Green, Red, Blue
5 cores: Yellow, Green, Red, Blue, Yellow/Green
(Other identification schemes available upon request.)

Fire Performance Characteristics
This product is an environmentally friendly low-smoke zero-halogen flame retardant cable. During a fire, it provides the following key safety features:

6.1 Flame Retardancy
- Single cable flame test (IEC 60332-1-2): A single cable will not continuously propagate flame along its length; the flame self-extinguishes.
- Bunched cable flame test (IEC 60332-3-24): When cables are installed in bunches, the flame propagation distance is limited (≤ 2.5 m), and the fire self-extinguishes within the specified time.
- Flame retardant classes are divided into Class A, B, C, and D, with Class A being the most stringent.

6.2 Halogen-Free Property (IEC 60754-1)
The cable material does not contain halogen elements. The total halogen acid gas content during combustion is very low (typically below 5 mg/g), and no highly toxic corrosive gases such as HCl or HF are produced.

6.3 Low Corrosivity (IEC 60754-2)
The aqueous solution of the gases evolved during combustion has a pH value of not less than 4.3 and a conductivity of not more than 10 µS/mm. This indicates that the combustion gases have very low corrosivity and will not cause severe corrosive damage to electronic equipment or building structures.

6.4 Low Smoke Property (IEC 61034-2)
The smoke density during cable combustion is very low, with a minimum light transmittance of ≥ 60%. This ensures clear visibility for personnel evacuation at the fire scene and facilitates fire rescue operations.

6.5 Oxygen Index
The oxygen index of the sheath material is not lower than 32%. The material is not easily ignitable and does not contribute to flame spread.

Product Advantages
- Sound electrical performance: XLPE insulation features high insulation resistance, low dielectric loss, and good voltage withstand characteristics.
- Strong heat resistance: The continuous conductor operating temperature can reach 90 °C, and the short-circuit temperature can reach 250 °C, significantly higher than standard PVC insulated cables (70 °C).
- High mechanical strength: XLPE material has good resistance to crushing, abrasion, and environmental stress cracking.
- Environmentally safe: The material is completely halogen-free. During combustion, smoke is minimal, no toxic gases are released, and gas corrosivity is very low, meeting green environmental requirements.
- Reliable flame retardant performance: Strictly tested according to the IEC 60332 series of standards, effectively preventing fire from spreading along the cable.
- TÜV certified: Some products have passed TÜV international certification, with product quality and safety verified by an authoritative third party.

Applicable Scenarios
This product is widely used in various locations with high fire protection and safety requirements:

- Civil buildings: High-rise buildings, large shopping malls, hospitals, hotels, residential buildings and other densely populated places.
- Transportation facilities: Subways, light rail, urban rail transit, tunnels, airport terminals, parking lots.
- Energy facilities: Power stations, renewable energy generation facilities (e.g., photovoltaic power plants, wind power plants).
- Industrial facilities: Petrochemical plants, industrial and mining enterprises.
- Critical facilities: Data centers, broadcasting and television stations, telephone exchange rooms, nuclear power plants.
- Public facilities: City squares, theatres, exhibition centers, chemical plants.
- Special locations: Ships and offshore oil platforms (marine power cables), fire-fighting equipment power supply lines.

Note: This cable is generally intended for fixed installations and suitable for building wiring. It should not be directly buried underground or installed in conduits without armour (select armoured type for direct burial).

Installation Methods
The cable can be installed using the following methods:
- In conduits
- In cable trenches
- In tunnels
- In shallow troughs
- In intermediate floors
- Supported overhead installation
- Suspended overhead installation
- Other methods as appropriate for the specific construction.

Product Certification and Marking
This product is designed and manufactured in accordance with international standards such as IEC 60502-1 and has passed the following certifications and tests:
- TÜV certification – Product certified by the German Technical Inspection Association.
- IEC system conformity testing – Including all IEC fire performance tests for flame retardancy, halogen-free, low smoke, and low corrosivity.
- Conductor complies with IEC 60228 Class 2 requirements (Class 5 flexible conductors can be applied when suitable).
- The cable surface is marked with information such as product type, voltage rating, manufacturer's mark, and flame retardant class for easy on-site identification.