Detailed Description
What Is a Building / House Wiring Cable?
A building wiring cable is a single-core PVC insulated non-sheathed wire designed for fixed installation inside electrical conduit, trunking, and surface-mounting systems in residential, commercial, and light industrial buildings. It is the wire that an electrician pulls through conduit every day — the brown wire for the lighting switched live, the blue wire for the neutral, the green-yellow wire for the earth.
In the IEC world, this cable is designated 60227 IEC 01 (solid conductor, known as BV in China) or 60227 IEC 02 (stranded conductor, known as BVR in China). In the CENELEC harmonized system, the equivalent designations are H07V-U (solid) and H07V-R (stranded). The voltage rating is 450/750 V — the standard for fixed building wiring — which provides sufficient insulation coordination for 230/400 V residential and commercial electrical systems.
The key characteristic of building wiring cable is that it is non-sheathed — a single insulated conductor, not a multi-core cable with an outer sheath. The mechanical protection is provided by the conduit or trunking system in which it is installed. This design allows the electrician to pull individual wires to each point in the circuit, selecting the correct color for each function (phase, neutral, earth) and the correct cross-section for each circuit's load current.
Solid vs Stranded Conductor — Which for Which Application?
| Parameter | Solid Conductor (BV / H07V-U) | Stranded Conductor (BVR / H07V-R) |
|---|---|---|
| Conductor class | IEC 60228 Class 1 | IEC 60228 Class 2 |
| Cross-section range | 1.5–6 mm² | 1.5–400 mm² |
| Flexibility | Rigid — holds its shape after bending | Semi-flexible — can be routed around corners without spring-back |
| Termination | Direct insertion into screw and cage-clamp terminals; no ferrule required | Requires ferrule for cage-clamp terminals ≥10 mm²; crimped lug for screw terminals ≥16 mm² |
| Best for | Lighting and socket circuits ≤6 mm² in conduit — one-time pull, permanent installation | Distribution board wiring, sub-main circuits ≥10 mm², any application where the wire must be routed through confined spaces |
| Cost | Lower — simpler manufacturing | Slightly higher — additional stranding step |
Solid conductor is the default for lighting (1.5 mm²) and socket (2.5 mm²) circuits — the standard domestic wiring cross-sections. The wire is pulled once, terminated, and never moved. Stranded conductor is used for distribution circuits (10–25 mm² sub-mains) and for internal wiring inside distribution boards where the flexibility of stranded wire makes it possible to route conductors neatly between devices in the confined space of a consumer unit.
Color Coding — The Language of Electrical Wiring
Correct color identification is the first line of defense against wiring errors. The harmonized European color code per HD 308 S2 (and adopted by most IEC countries) is:
| Conductor Function | Color (HD 308 S2) | Common Legacy Colors |
|---|---|---|
| Line / Phase (L1) | Brown | Red (old UK), Black (old Germany) |
| Line / Phase (L2) | Black | Yellow (old UK), Blue (old Germany) |
| Line / Phase (L3) | Grey | Blue (old UK) |
| Neutral (N) | Blue | Black (old UK, old Germany) |
| Protective Earth (PE) | Green-Yellow (bi-color) | Green (old); bare (in some conduit systems) |
Yichi building wires are manufactured in all standard colors. The insulation color is integral to the PVC compound — it is not a surface coating — so it does not rub off during pulling and remains identifiable for the life of the installation. For markets with national color code deviations (e.g., North American: black/red/blue phases, white neutral, green earth), custom color coding is available on request.
Installation Best Practices
- Conduit fill: The total cross-sectional area of all wires in a conduit must not exceed 40% of the conduit's internal cross-sectional area (for conduits longer than 3 m with up to 3 bends). Exceeding this limit makes pulling difficult and can damage the insulation through friction heating during pulling
- De-rating for grouping: When more than three current-carrying conductors are installed in the same conduit, the current-carrying capacity (ampacity) of each conductor must be de-rated per IEC 60364-5-52 Table B.52.17. For example, 6 current-carrying conductors in one conduit → de-rating factor 0.57 → a 2.5 mm² wire rated 19.5 A (clipped direct) drops to 11.1 A
- Conductor identification: Every conductor must be identifiable at every accessible point — at the distribution board, at every junction box, at every accessory. Do not rely on "tracing the wire" — the color coding is the identification
- Earth conductor: In most national wiring regulations, the protective earth conductor must be green-yellow throughout its length. It cannot be an over-sleeved conductor of another color — the insulation color must be green-yellow from manufacture. Yichi earth conductors are green-yellow bi-color extruded as standard
- Do not paint or cover: The PVC insulation is the electrical safety barrier. Painting, plastering over, or covering the insulation with tape or sleeving that is not rated for the voltage compromises the insulation system. If a wire needs a different color at the termination, use an appropriately rated identification sleeve over the visible portion only
Why Choose Yichi Building Wiring Cables
- IEC 60227-3 compliant — the definitive standard for building wire: Every production batch is tested for conductor resistance, insulation thickness, high-voltage withstand, and flame retardance per the full IEC 60227 test schedule. The standard is not optional — it is the minimum
- Solid and stranded conductors from a single manufacturer: BV (solid) and BVR (stranded) types across the full 1.5–400 mm² range — one supplier for the complete building wiring specification, from the 1.5 mm² lighting circuit wire to the 240 mm² main feeder between the meter and the consumer unit
- Color coding to your national standard: HD 308 S2 harmonized colors as standard; custom color codes for national markets that deviate from the European harmonized system; bi-color green-yellow earth conductor manufactured with true co-extrusion, not surface painting
- CPR Euroclass Eca as standard: All building wire is CPR-classified to Eca minimum, meeting the legal requirement for cable placed on the EU market for permanent installation in buildings. Dca class available on request with enhanced flame-retardant PVC
- Full coil and drum packaging: Standard lengths of 100 m coils for small cross-sections (1.5–6 mm²) used by electrical contractors; 500 m and 1 000 m drums for larger cross-sections used in commercial and industrial projects