2491X / H05V-K is a single-core, non-sheathed Class 5 flexible plain annealed copper conductor cable insulated with flame-retardant Polyvinyl Chloride (PVC). Standardized under BS EN 50525-2-31 and IEC 60227-3, it is engineered exclusively for internal fixed or flexible wiring in dry, enclosed environments at rated voltages up to 300/500V [1]. Featuring a +70°C maximum conductor operating temperature, its high flexibility allows tight bending radii inside control panels, switchgear, relay racks, lighting luminaires, and enclosed trunking or conduit systems where mechanical protection is provided by the enclosure.
Technical Specifications and Application Matrix
The table below contrasts the design parameters and permitted application scenarios of 2491X / H05V-K against higher-voltage and outdoor-rated cable types:
| Technical Parameter | 2491X / H05V-K | 6491X / H07V-R | H07RN-F | 6941X (SWA) |
| Harmonized Standard | BS EN 50525-2-31 | BS EN 50525-2-31 | BS EN 50525-2-21 | BS 5467 / IEC 60502-1 |
| Rated Voltage () | 300/500V | 450/750V | 450/750V | 600/1000V |
| Conductor Class | Class 5 Flexible [2] | Class 2 Stranded [2] | Class 5 Flexible [2] | Class 2 Stranded [2] |
| Insulation Type | General Purpose PVC | General Purpose PVC | EPR Rubber | XLPE (Cross-linked Poly) |
| Armor / Outer Sheath | None | None | Polychloroprene (PCP) | Steel Wire Armor (SWA) |
| Max Operating Temp. | +70°C | +70°C | +90°C | +90°C |
| Primary Installation | Internal Control Panels | Building Power Conduits | Heavy-Duty Flexible | Direct Burial / External |
Permitted Primary Application Scenarios
Control Panels, Switchgear, and Relay Racks
2491X / H05V-K is the industry standard for internal panel wiring. The Class 5 fine-wire copper conductor facilitates tight routing around DIN rails, terminal blocks, and trunking channels without inducing mechanical stress on connection terminals.
- Voltage Compliance: Rated for control circuits operating up to 500V AC (or 300V relative to earth ground).
- Flame Retardancy: Fully compliant with IEC 60332-1-2 single-cable vertical flame propagation testing [3].
Closed Conduit and Surface-Mounted Trunking Systems
When used for power or signaling outside an equipment enclosure, BS EN 50525-2-31 permits H05V-K solely inside protected closed systems:
- Rigid/Flexible PVC & Steel Conduits: Must be installed within dry indoor spaces to protect the non-sheathed PVC insulation from mechanical abrasion and liquid contact.
- Cable Trunking and Dado Rails: Used for internal distribution in commercial buildings where circuit modifications require easy pulling through tight bends.
Lighting Luminaires and Appliance Internal Interconnects
The cable’s thin insulation wall and high flexibility make it suitable for internal connections inside electrical equipment:
- Internal Luminaire Wiring: Connecting ballasts, LED drivers, and emergency power units within closed light fittings.
- Domestic and Commercial Appliances: Fixed internal jumpers in heating controls, switchboards, and small machinery units operating under steady-state thermal loads below +70°C.
Prohibited Applications and Installation Hazards
- Outdoor Fixed Wiring: Standard PVC lacks carbon black and UV stabilizers, leading to rapid photo-oxidation, micro-cracking, and insulation breakdown under direct solar radiation.
- Direct Burial or Wet Environments: Lacking an overall protective sheath or armor (such as BS 5467 XLPE/SWA/PVC), moisture ingress degrades insulation resistance ().
- High-Temperature Circuits: For environments exceeding +70°C, high-temperature heat-resistant equivalents like Tri-Rated / BS 6231 (+105°C) or H05V2-K (+90°C) must be specified [4].
References
[1] Wikipedia. IEC 60227 [EB/OL]. 2026-09-24.
[2] Wikipedia. IEC 60228 [EB/OL]. 2026-09-24.
[3] Wikipedia. IEC 60332 [EB/OL]. 2026-09-24.
[4] Wikipedia. BS 6231 [EB/OL]. 2026-09-24.