A Professional Engineering Guide for EPC Contractors, Electrical Engineers, and Developers | Covering a Full Range of Low-Voltage (0.6/1kV) and Medium-Voltage (6–35kV) Products
In modern urban development—particularly in high-rise residential buildings, densely populated public facilities, underground utility tunnels, and transportation tunnels—traditional PVC cables pose significant fire safety risks. When burning, they release toxic, corrosive halogen gases and dense black smoke, which can easily lead to secondary casualties and equipment damage. Consequently, Low-Smoke Zero-Halogen (LSZH) cables have become a mandatory safety requirement for high-standard residential and public power projects both domestically and internationally.
Unlike standard flame-retardant cables, LSZH cables utilize halogen-free polyolefin materials for their insulation and outer sheathing. When exposed to fire, these cables emit no toxic halogen gases and maintain extremely low smoke density, thereby facilitating safe personnel evacuation while effectively protecting electrical assets. This article provides an in-depth analysis of LSZH cables suitable for low-voltage distribution and medium-voltage backbone networks. It covers key advantages, technical specifications, IEC and GB compliance requirements, application scenarios, and real-world engineering case studies, offering practical guidance on cable selection for construction and design teams.
LSZH cables completely eliminate chlorine, bromine, and all other halogen elements from their raw materials. When exposed to flames or high-temperature combustion, they effectively prevent the three major secondary hazards associated with traditional plastic cables:
- High light transmittance (≥80%): Maintains clear visibility within enclosed buildings, significantly improving escape efficiency during fire emergencies.
- No corrosive halogen gases: Prevents acidic gas corrosion of metal supports, switchgear, cable joints, and structural steel, thereby substantially reducing post-fire restoration costs.
- Non-toxic and eco-friendly combustion residues: Complies with global standards for green building, fire safety, and low-carbon infrastructure.
LSZH solutions cover two voltage classes:
- Low Voltage (LV) 0.6/1kV: Suitable for terminal power distribution within buildings, elevators, lighting, and fire emergency circuits.
- Medium Voltage (MV) 6kV–35kV: Suitable for municipal utility tunnel trunk lines, substation feeder lines, and main power supplies for large-scale complexes.
All performance metrics for Jinhong LSZH (Low Smoke Zero Halogen) cables strictly adhere to unified international and domestic specifications, meeting dual certification requirements for both cross-border and local projects:
- IEC 60754-1/2: Halogen content testing
- IEC 61034: Smoke density (light transmittance) testing
- IEC 60332-3: Vertical flame spread classification for bunched cables
- GB/T 17650: Low smoke zero halogen testing specifications
- GB/T 18380-2023: Latest flame combustion assessment standards
- GB/T 12706: General requirements for low- and medium-voltage XLPE power cables
China's GB standards adopt an equivalent IEC technical framework, ensuring full alignment in core safety performance while incorporating supplementary provisions for local adaptability to high-altitude and hot, humid environments. LSZH cables certified to both IEC and GB standards satisfy tender requirements in overseas markets—such as Africa and Southeast Asia—while also meeting acceptance criteria for domestic municipal engineering projects.
Test conditions: Copper conductor with XLPE insulation, standard atmospheric pressure, ambient temperature 25°C.
| Test Parameter | 0.6/1kV Low Voltage LSZH Cable | 6–35kV Medium Voltage LSZH Cable | Mandatory Standard Basis |
|---|---|---|---|
| Continuous long-term operating temperature | 90°C | 90°C | IEC 60287 / GB/T 16895 |
| Short-circuit withstand temperature (≤5s) | 250°C peak | 250°C peak | Global unified cable thermal standard |
| Halogen gas release content | 0% zero halogen | 0% zero halogen | IEC 60754-2 |
| Smoke light transmittance after burning | ≥80% | ≥80% | IEC 61034 low smoke requirement |
| Optional flame retardant grade | ZA/ZB/ZC | ZA high-grade flame retardant | IEC 60332-3 bundle burning test |
| Minimum construction bending radius | 10 * cable outer diameter | 15 * cable outer diameter | On-site wiring construction norms |
| Typical cable model | WDZ-YJY, WDZN-YJY | WDZ-YJY23, WDZN-YJV22 armored | Universal engineering model specification |
| Core application positioning | Indoor terminal power distribution, emergency lighting | Underground trunk transmission, key public substation lines | Public & residential power system layout rules |
- High-rise residential projects: Indoor power distribution, corridor public lighting, elevator power supply, and emergency circuits for fire pumps and smoke exhaust systems
- High-occupancy public buildings: Hospitals, primary and secondary schools, large shopping malls, exhibition centers, and office buildings
- Enclosed indoor spaces: Underground parking garages, vertical cable shafts, and indoor cable trenches
- Green, low-carbon residential communities: Integrated power cabling systems compliant with LEED and domestic green building certification standards
- Municipal underground infrastructure: Main lines for urban utility tunnels; power feeders for expressways and subway tunnels
- Public power distribution hubs: Community substations and municipal medium-voltage backbone grids
- Super-high-rise landmark complexes: Main power supply lines for the building
- Public facilities in coastal and humid environments: Corrosion-resistant LSZH armored cables suitable for long-term enclosed underground installation
Project Requirements: Upgrade and replace aging PVC wiring in a 32-story residential complex; elevator and fire emergency circuits required non-toxic, low-smoke cables to comply with the latest residential fire safety codes.
Cable Selected: 0.6/1kV WDZ-YJY Flame-Retardant, Low-Smoke Zero-Halogen (LSZH) Copper-Core Cable
Actual Outcome: Eliminated the risk of dense, toxic smoke filling corridors during a fire; successfully passed local fire department inspection; significantly enhanced resident evacuation safety without a substantial budget increase.
Project Requirements: High-density cable installation within fully enclosed municipal utility tunnels posed a significant risk of cross-propagation of flames; cables were required not to release corrosive acidic gases during combustion to prevent damage to metal supports and monitoring equipment.
Cable Selected: 8.7/15kV WDZ-YJY23 Armored, Low-Smoke Zero-Halogen (LSZH) Medium-Voltage Cable
Actual Outcome: Passed rigorous IEC vertical flame spread tests for bunched cables; effectively inhibited flame propagation between cable groups; generated no corrosive gases during combustion; fully compliant with national standards for municipal utility tunnel construction.
Project Requirements: Medical facilities have stringent fire safety requirements; fire protection equipment and central power supply systems must not generate secondary toxic pollution during a fire.
Selected Cable Configuration: 0.6/1kV WDZN low-smoke, zero-halogen, flame-retardant cables for medical emergency equipment; 26/35kV WDZ-YJY23 low-smoke, zero-halogen, flame-retardant armored cables for the hospital's main incoming power circuits.
Actual Outcome: Full coverage of low-smoke, zero-halogen cables across the hospital's entire network; ensured clear evacuation routes and the stable operation of life-support medical equipment during fire incidents, meeting international electrical safety standards for medical buildings.
- Mandatory LSZH (Low Smoke Zero Halogen) Standard: The use of standard PVC cables is strictly prohibited in all enclosed spaces, densely populated public buildings, high-rise residential buildings, tunnels, and municipal utility tunnels; LSZH is the minimum safety requirement.
- Voltage Rating Principles: Use 0.6/1 kV low-voltage LSZH cables for indoor terminal power distribution; use 6–35 kV medium-voltage LSZH cables for long-distance underground main power transmission in public infrastructure projects.
- Flame Retardancy Matching: For cable trenches and tunnels with high cable density, select the highest flame-retardant grade (Grade ZA); for common areas in standard residential buildings, Grades ZB or ZC may be used to balance safety performance with procurement costs.
- Installation Environment Optimization: For direct burial, road crossings, and outdoor exposed installations, armored LSZH cables with compression and UV resistance (e.g., Type YJY23) must be used.
- Certification Priority: Prioritize suppliers capable of providing comprehensive IEC CB, CE, and GB test reports to avoid disqualification during the bidding process or failure to pass on-site acceptance inspections in international projects.
LSZH (Low Smoke Zero Halogen) cables represent a mainstream safety upgrade for modern residential and public power infrastructure. Compared to traditional PVC cables, they fundamentally eliminate secondary fire hazards such as toxic gas corrosion and smoke-induced visibility loss. With a comprehensive product range covering both medium- and low-voltage applications and compliance with both IEC and GB standards, LSZH cables have become the preferred choice for high-rise residential, municipal infrastructure, healthcare, and commercial building projects worldwide.
The standardized application of LSZH cables significantly enhances the fire safety of power distribution systems, reduces long-term operational and maintenance risks, and ensures compliance with increasingly stringent international fire safety and green building regulations.
Jinhong Cable offers a complete range of LSZH power cables, including 0.6/1kV low-voltage and 6–35kV medium-voltage options. All products hold authoritative IEC and GB safety certifications and deliver consistent low-smoke, zero-halogen performance, making them widely used in residential, municipal, hospital, and public infrastructure projects across Africa, Southeast Asia, the Middle East, and Latin America.
