H05VV-F vs H05Z1Z1-F (318-B): Key Differences in PVC and LSZH Flexible Cables
H05VV-F and H05Z1Z1-F (commonly designated as 318-B under BS 6500 / EN 50525) are light-duty, 300/500V rated flexible cables designed for internal wiring and mobile appliance connections. The fundamental distinction lies in their insulation and sheathing compounds. H05VV-F uses polyvinyl chloride (PVC), whereas H05Z1Z1-F utilizes Low Smoke Zero Halogen [1] (LSZH / LSOH) thermoplastic materials. During fire exposure, H05VV-F emits dense smoke and corrosive hydrogen chloride (HCl) gas. In contrast, H05Z1Z1-F significantly limits toxic gas emissions and acid gas release, making it mandatory for high-occupancy environments with strict fire safety regulations.
Technical Parameter Comparison Matrix
| Parameter | H05VV-F | H05Z1Z1-F (318-B) | Standard Reference |
| Rated Voltage () | 300/500V | 300/500V | EN 50525-2-11 / EN 50525-3-11 |
| Conductor Type | Class 5 Flexible Plain Annealed Copper | Class 5 Flexible Plain Annealed Copper | IEC 60228 [2] / BS EN 60228 |
| Insulation Material | PVC (Type TI 2) | LSZH Thermoplastic (Type EI 5 / TI 7) | EN 50363-3 / EN 50363-7 |
| Sheath Material | PVC (Type TM 2) | LSZH Thermoplastic (Type TM 7) | EN 50363-4-1 / EN 50363-8 |
| Operating Temperature | -15°C to +70°C | -15°C to +70°C | EN 50525 series |
| Flame Retardancy | IEC 60332-1-2 | IEC 60332-1-2 | IEC 60332-1-2 |
| Smoke Density | High smoke emission | Light transmittance 60% | IEC 61034-2 |
| Halogen Acid Gas Emission | Acid gas released ( HCl) | Zero Halogen ( HCl) | IEC 60754-1 / IEC 60754-2 |
| Corrosivity (pH & Conductivity) | Low pH (), High conductivity | pH 4.3, Conductivity | IEC 60754-2 |
Fire Performance and Material Decomposition
- H05VV-F (PVC Sheathed): Under direct thermal stress, PVC releases toxic halides, mainly hydrogen chloride (HCl). HCl gas reacts with atmospheric moisture to form hydrochloric acid, accelerating equipment corrosion and presenting severe health hazards to building occupants during evacuation.
- H05Z1Z1-F (LSZH Sheathed): Formulated with inorganic hydrated fillers (such as Aluminium hydroxide [3] or Magnesium Hydroxide), LSZH compounds undergo endothermic decomposition when burned. This process releases water vapor to suppress flame spread while maintaining smoke density to strict IEC 61034-2 thresholds.
Compliance and Application Scenarios
- H05VV-F Applications: Standard indoor commercial and residential installations, including household appliances, office computers, lighting fixtures, and temporary power cords in low-density occupancies.
- H05Z1Z1-F (318-B) Applications: High-density public spaces, hospitals, airports, railway stations, and data centers where compliance with European Construction Products Regulation [4] (CPR) smoke classification (e.g., ) is required.
- Standard Compliance: Both cable types conform to EN 50525 requirements for harmonized flexible cables, with H05Z1Z1-F specifically fulfilling BS 7211 / BS 6500 specification updates for low-emission installations.
CJDL CABLE Engineering Insight
While H05VV-F remains suitable for standard indoor commercial and residential wiring, H05Z1Z1-F (318-B) is the engineering-recommended choice for high-occupancy public spaces, where limited smoke and zero halogen emission directly support occupant safety during evacuation. All flexible cables manufactured by CJDL CABLE are produced and routinely tested to EN 50525, IEC 60332-1-2 and IEC 60754-2, delivering consistent fire performance.
References
[1] Wikipedia. Low smoke zero halogen [EB/OL]. 2026-09-11.
[2] Wikipedia. IEC 60228 [EB/OL]. 2026-09-11.
[3] Wikipedia. Aluminium hydroxide [EB/OL]. 2026-09-11.
[4] Wikipedia. Construction Products Regulation [EB/OL]. 2026-09-11.