A Comparative Analysis of Polymeric Cable Insulations (XLPE & LSZH): Fire Dynamics, Operational Integrity, and Environmental Impact

Abstract

The choice of materials for electrical power cable insulation has a profound impact on fire safety, operational reliability, and environmental impact. This review compared the fire dynamics, operational performance, and environmental impact of cross-linked polyethylene (XLPE) and low-smoke, zero-halogen (LSZH) cable insulation materials. XLPE has a good thermal rating for continuous operation with mechanical strength at 90°C and short-circuit withstand capability at 250°C [12], low smoke production, and better electrical performance than PVC [6]. LSZH contains mineral fillers that release water vapour upon decomposition and retard combustion of the material [2]. According to the cone calorimeter test, LSZH cable insulation recorded 46 to 53 s time to ignition compared to 18 to 25 s for XLPE [5]. A lower peak heat release rate was also observed for LSZH with a value of 185.3 kW/m² against 243.98 kW/m² for XLPE [5]. The cable insulation material did not produce hydrogen chloride gas on combustion [13].

Introduction

The text provides a comparative review of XLPE and LSZH cable insulation materials, focusing on their causes of failure, fire behaviour, testing methods, operational performance, environmental effects, and applications.

• Electrical cables are significant fire hazards in domestic, industrial, commercial, and transport environments. Cable fires can result from short circuits, overloads, poor connections, insulation ageing, manufacturing defects, and external flames. In marine applications, engine rooms account for a large proportion of reported ship fires.
• Cable insulation is essential because it electrically and mechanically protects conductors while resisting environmental, thermal, and fire-related stresses. An effective insulation material should have high dielectric strength, good mechanical and thermal properties, fire resistance, adequate service life, and reasonable cost.
• Fire-resistant insulation is particularly important in enclosed environments because smoke and toxic gases can reduce visibility, hinder evacuation, and damage equipment. PVC, although flame-retardant, produces dense smoke and corrosive hydrogen chloride gas when burned, increasing fire-related risks.
• XLPE (Cross-linked Polyethylene) has excellent electrical, mechanical, and thermal properties. It can operate continuously at about 90°C and withstand 250°C during short-circuit conditions. It is widely used in high-voltage, underground, submarine, industrial, and outdoor power cables. However, XLPE is combustible and produces relatively high heat and smoke during combustion.
• LSZH (Low Smoke Zero Halogen) was developed to reduce the smoke and corrosive gases associated with conventional cable materials. Its metal-hydroxide additives absorb heat and release water vapour during decomposition, helping to reduce heat release and smoke. LSZH produces no halogen-based acidic gases and forms a protective char layer during combustion.
• In terms of fire behaviour, LSZH generally performs better than XLPE. At a heat flux of 50 kW/m², LSZH showed a longer time to ignition (46–53 s) compared with XLPE (18–25 s) and a lower peak heat release rate (185.3 kW/m²) than XLPE (243.98 kW/m²).
• Smoke production is a major advantage of LSZH. The reported total smoke release was about 596.5 m²/m² for LSZH, compared with 150 m²/m² for XLPE and 2350.6 m²/m² for PVC in the cited results. LSZH therefore provides greater visibility and reduced smoke-related hazards during fires.
• XLPE has stronger mechanical properties, including tensile strength, abrasion resistance, and impact resistance. LSZH generally sacrifices some mechanical performance because of the incorporation of flame-retardant hydroxide additives.
• Both materials have similar thermal performance and expected service life, with typical insulation service life reported at approximately 30–40 years.
• The vertical cable flame test is used to evaluate flame spread, burning duration, char length, self-extinguishing behaviour, molten dripping, and afterglow. Relevant standards include IEC 60332 and Indian standards such as IS 10810.
• The cone calorimeter test evaluates fire performance through parameters such as time to ignition, heat release rate, total heat release, smoke production, mass loss, residual mass, gas generation, and fire growth rate. Increasing heat flux generally reduces ignition time and increases peak heat release.
• Application suitability differs between the materials: XLPE is better suited to high-voltage power transmission and distribution because of its superior mechanical and electrical properties, while LSZH is more suitable for enclosed, public, transport, data-centre, and other fire-critical environments where low smoke and low corrosivity are priorities.
• Although LSZH is generally more expensive and may require more skilled installation, its improved fire safety can justify the additional cost in high-risk environments.
• Future research may focus on AI and machine-learning prediction of cable fires and material performance, nano-additives, graphene-based insulation, hybrid flame retardants, and environmentally friendly insulation materials.

Conclusion

A. Summary of Findings From the analysis, it was established that LSZH material offers better fire protection than XLPE material [1][2][5]. LSZH insulation records a longer time to ignition (TTI) and lower peak heat release rate (PHRR) compared to XLPE [5]. LSZH produces less smoke and toxic gases than XLPE, thus making it safer for use in enclosed environments [1][5]. The mechanical properties of XLPE are better than LSZH [6], and as a result, XLPE is suitable for use in high-voltage power transmission and distribution networks [6][12]. XLPE and LSZH materials have comparable thermal performance and similar service life [7][8][12]. B. Key takeaways 1) The choice of insulation material depends on the intended application [1][3][6]. 2) Higher filler loading enhances the fire protection performance of LSZH, but compromises its mechanical properties [2][6]. 3) Regulatory requirements will continue to drive the adoption of LSZH materials in various applications [1]. 4) Future possibilities include exploring nano-additives and hybrid flame retardants in the production of advanced cable insulation materials [9]. 5) Various standards can be used to compare the performance characteristics of XLPE and LSZH materials [6][14][15]. C. Recommendations 1) Use LSZH material in enclosed environments where fire safety is a concern [1]. 2) Use XLPE material in high-voltage power transmission and distribution networks [6][12]. 3) Consider using LSZH material coating for XLPE power cables to enhance their fire performance [1][2]. 4) Follow the relevant standards when making decisions regarding the adoption of XLPE or LSZH materials [6][13][14][15]. 5) Make informed decisions based on the latest trends and developments in cable insulation materials [3][4][9].

References

[1] Casals-Torrens, P., & Castells, M. (2018). Use of Low Smoke and Halogen Free Cables for Marine Fire Safety Design. Naše more, 65(3), 1-6. [2] Matteucci, V., et al. (2024). Crystallinity of Halogen-Free Flame-Retardant Polyolefin Compounds Loaded with Natural Magnesium Hydroxide. Eng, 5, 2050-2066. [3] Saleh, M. A., et al. (2025). A Review on the Lifetime Estimation Methods of XLPE Power Cables. IEEE Open Journal of Industry Applications. [4] Gugulothu, B. N., et al. (2024). A study of XLPE insulation failure in power cables under electromagnetic stress. Engineering Research Express, 6, 035352. [5] Jicable\'15. (2015). Heat release measurement and cone calorimeter testing of cable materials. [6] IS 7098-2:2011. Crosslinked Polyethylene Insulated Thermoplastic Sheathed Cables. [7] Lin, J., & Cai, L. (2020). Research on the thermal ageing life prediction of XLPE cable. Journal of Physics: Conference Series, 1570, 012050. [8] Shan, B., et al. (2022). Residual Life Prediction of XLPE Distribution Cables. Polymers, 14, 5478. [9] Porfyris, A. D., et al. (2024). Flame-Retarded and Heat-Resistant PP Compounds. Polymers, 16, 1298. [10] EMSA. (2015). Annual overview of marine casualties and incidents. EMSA. [11] DNV. (2001). Engine room fires can be avoided. [12] IEC 60502-2 (2014). Power cables with extruded insulation. [13] IEC 60754-1 (2011). Test on gases evolved during combustion of materials from cables. [14] ISO 5660-1 (2015). Reaction-to-fire tests -- Heat release rate. [15] IEC 60332-1-2 (2004). Tests on electric and optical fibre cables under fire conditions.

Copyright

Copyright © 2026 Tejsingh Patle, Rudrasinh Vaghela, Dinesh Matangi, Harshit Ray, Dhiraj Sharma, Nathan Khobragade. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.