H05VV-F vs 318-B LSZH (H05Z1Z1-F): Core Differences for Indoor Wiring
H05VV-F and 318-B (H05Z1Z1-F) are light-to-medium-duty, 300/500V flexible harmonized cables used for indoor power connections, but they differ fundamentally in insulation material and fire safety performance. H05VV-F utilizes standard Polyvinyl Chloride (PVC) for both insulation and outer sheath, providing good mechanical flexibility and moisture resistance up to 70°C. In contrast, 318-B (H05Z1Z1-F) uses Low Smoke Zero Halogen (LSZH) thermoplastic compounds rated up to 70°C or 90°C (depending on the specific standard variant). When exposed to fire, 318-B releases non-corrosive gases and minimal smoke, whereas H05VV-F emits dense smoke and toxic hydrogen chloride gas.
Technical Parameter Comparison Matrix
| Technical Parameter | H05VV-F Flexible Cable | 318-B (H05Z1Z1-F) LSZH Cable |
| Harmonized Code Designation | H05VV-F | H05Z1Z1-F |
| Applicable Global Standards | IEC 60227-5, BS EN 50525-2-11 | BS EN 50525-3-11, BS 6500 (318-B reference) |
| Rated Voltage () | 300/500 V | 300/500 V |
| Conductor Type | Class 5 Flexible Plain Annealed Copper | Class 5 Flexible Plain Annealed Copper |
| Insulation Material | PVC (Polyvinyl Chloride) | Thermoplastic LSZH (Low Smoke Zero Halogen) |
| Outer Sheath Material | PVC (Polyvinyl Chloride) | Thermoplastic LSZH (Low Smoke Zero Halogen) |
| Maximum Operating Temp | 70°C | 70°C (or 90°C for high-temp rated variants) |
| Fire Behavior & Smoke Emission | Standard flame retardant; emits dense smoke & acid gas | Flame retardant to IEC 60332-1-2; Low Smoke Zero Halogen |
| Acid Gas Emission | > 15% HCl emission (IEC 60754-1) | Halogen-free, pH , conductivity |
Fire Safety and Environmental Hazards
The primary differentiator between these cables lies in their reaction to fire:
- H05VV-F (PVC Sheathed): Emits chlorine gas upon combustion, reacting with ambient moisture to form hydrochloric acid. This degrades sensitive electronic equipment and presents severe health risks in unventilated areas.
- 318-B H05Z1Z1-F (LSZH Sheathed): Complies with IEC 60754-1/2 (zero halogen emission) and IEC 61034-2 (transmittance/smoke density test). It ensures high visual visibility during evacuation and eliminates corrosive acid gas risks.
Application Scenarios and Installation Selection
Selection depends entirely on building codes, fire hazard risk, and human occupancy density:
- Select H05VV-F for:
- Standard domestic indoor wiring in low-density residential spaces.
- Portable household appliances (e.g., washing machines, refrigerators, office machinery).
- Dry and damp indoor environments without specific public safety restrictions.
- Select 318-B (H05Z1Z1-F) for:
- Public access buildings, hospitals, schools, airports, and commercial centers.
- Enclosed areas with high occupant density or limited emergency egress routes.
- Installations near sensitive electronic hardware, data centers, and control systems requiring protection from acid corrosion during a fire.
Real-World Application: In hospital and school renovation projects supplied by CJDL CABLE, replacing conventional H05VV-F wiring with 318-B H05Z1Z1-F cables fully satisfied local fire safety regulations for high-occupancy buildings, without compromising circuit performance for indoor power and control connections.
CJDL CABLE Engineering Insight: The key consideration when choosing between H05VV-F and H05Z1Z1-F (318-B) is project fire safety requirements rather than basic electrical performance. Our engineering team recommends H05VV-F for conventional low-risk residential and general appliance wiring to control project budget, while specifying 318-B LSZH H05Z1Z1-F for public buildings and data-related installations to meet mandatory low-smoke zero-halogen fire codes and protect occupants and critical equipment.