WDZ-BYJ-450/750V
WDZ-BYJ Halogen-Free Building Wire, 450/750 V
Cross-linked halogen-free insulation in the 450/750 V building wire sizes, for the buildings where the smoke matters.
The BYJ part of the name is the insulator: a cross-linked polyolefin instead of PVC. Cross-linking changes the thermal picture entirely, because the compound no longer softens and flows when it is heated. A PVC/C wire is rated 70 °C continuous; a BYJ wire is rated 90 °C and holds 250 °C on short circuit, which is the same temperature a power cable insulation reaches.
The WDZ prefix is the fire performance: low smoke, zero halogen, and low toxicity. When a PVC wire burns it releases hydrogen chloride, which corrodes the equipment in the room and attacks the escape route. A halogen-free compound does not. That is why the specification changes by building type, and why a metro station, a hospital or a data centre specifies WDZ-BYJ where a house is wired in PVC.
Specification
| Item | Value |
|---|---|
| Rated voltage U0/U | 450/750 V |
| Conductor | Class 1 solid to 6 mm², Class 2 stranded from 10 mm², IEC 60228 |
| Cross-section range | 1.5 – 185 mm² |
| Insulation | Irradiated cross-linked halogen-free polyolefin, 0.7–1.6 mm nominal |
| Maximum conductor temperature | +90 °C continuous |
| Short-circuit temperature | 250 °C for 5 s |
| Minimum installation temperature | −15 °C |
| Smoke behaviour | Low smoke to IEC 61034-2, light transmittance above 60% |
| Acidity and toxicity | Halogen-free to IEC 60754, low toxicity |
| Flame behaviour | IEC 60332-3-24 for bunched wiring |
| Standard | GB/T 19666, JB/T 10491 |
| Supply form | 100 m coils as standard, or drums for the larger sizes |
Layer-by-layer construction
Listed from the conductor outward. Read this alongside the specification table — the two together tell you whether the cable will survive its installation method.
- 1. ConductorClass 1 solid annealed copper up to 6 mm²; Class 2 stranded from 10 mm², to IEC 60228
- 2. InsulationIrradiated cross-linked halogen-free polyolefin, 0.7–1.6 mm nominal wall, coloured
- 3. Surface and markingSmooth finish with printed marking at intervals: GB/T 19666, WDZ-BYJ, size, voltage rating
- 4. PackageSupplied in 100 m coils, shrink-wrapped and labelled; drums for 25 mm² and above
Reference dimensions and weights
| Nominal cross-section (mm²) | Conductor structure (n×mm) | Insulation thickness (mm) | Approx. overall diameter (mm) | Approx. weight (kg/km) | Max. DC resistance at 20 °C (Ω/km) | Current rating in conduit at 30 °C (A) |
|---|---|---|---|---|---|---|
| 1.5 | 1 × 1.38 | 0.7 | 2.9 | 21 | 12.1 | 18 |
| 2.5 | 1 × 1.78 | 0.8 | 3.5 | 32 | 7.41 | 25 |
| 4 | 1 × 2.25 | 0.8 | 4.0 | 46 | 4.61 | 33 |
| 6 | 1 × 2.76 | 0.8 | 4.5 | 64 | 3.08 | 43 |
| 10 | 7 × 1.35 | 1.0 | 6.0 | 112 | 1.83 | 59 |
| 16 | 7 × 1.70 | 1.0 | 7.1 | 165 | 1.15 | 80 |
| 25 | 7 × 2.14 | 1.2 | 8.8 | 257 | 0.727 | 105 |
| 35 | 7 × 2.52 | 1.2 | 10.0 | 347 | 0.524 | 131 |
Reference figures for preliminary sizing and drum planning. Overall diameter and weight vary with strand construction and sheath thickness tolerance; certified drawings are issued with each quotation.
Engineering characteristics
- Irradiated cross-linked insulation rated 90 °C continuous, against 70 °C for a PVC/C building wire.
- Short-circuit rating of 250 °C for 5 s, the same figure a cross-linked power cable carries.
- Halogen-free compound with no hydrogen chloride released when it burns, to IEC 60754.
- Low smoke to IEC 61034-2, with light transmittance above 60% in the smoke chamber test.
- Bunched wiring flame performance to IEC 60332-3-24, which is the test a vertical shaft demands.
- Current ratings higher than PVC wire of the same size, because the 90 °C rating permits more current.
- 450/750 V rating to GB/T 19666, in the same sizes and colours as a standard building wire.
Typical applications
- Hospitals, clinics and healthcare buildings
- Metro stations, tunnels and enclosed public transport buildings
- Data centres and telecommunications rooms
- Schools, theatres and enclosed assembly buildings
- High-rise residential escape routes and stairwells
- Commercial towers with a specified fire strategy
Ordering options
- 1.5–185 mm² in 100 m coils or on drums
- Solid Class 1 up to 6 mm², Class 2 stranded from 10 mm²
- Full colour range including green-yellow
- Flame-retardant and higher fire-performance grades on request
- Private-label coil labels and OEM printing
Standards manufactured to
- GB/T 19666
- JB/T 10491
- IEC 60332-3-24
- IEC 61034-2
- IEC 60754
- IEC 60228
Manufactured to other standards on request. Send the standard number with your RFQ and we will quote against it rather than against a near-equivalent.
Price and availability for WDZ-BYJ Halogen-Free Building Wire
Include cross-section, core count, voltage grade, route length and installation method — those five determine price more than anything else on the page.
- Engineer-reviewed before pricing
- Reference drawings issued with the quotation
- Free sample up to free sample up to 5 m
WDZ-BYJ Halogen-Free Building Wire — frequently asked questions
When is WDZ-BYJ required rather than BV?
When the fire strategy says so. It is the specification for buildings with enclosed escape routes or with equipment that must survive a fire: hospitals, metro stations, data centres, theatres and high-rise stairwells. In a house or a light commercial unit, PVC-insulated BV is correct and more economical, and no code requires the halogen-free compound.
Why is the current rating higher than for BV?
Because of the temperature class. A PVC/C wire is rated 70 °C continuous; a cross-linked BYJ wire is rated 90 °C. The same 2.5 mm² conductor can carry more current before the insulation reaches its limit. Use the 90 °C column of the current rating table, and derate for grouping in the same way as you would for a PVC wire.
What does the WDZ prefix mean?
It is the Chinese fire-performance code: W for low smoke, D for low toxicity, and Z for flame retardant. Together they say the compound is halogen-free, gives off little smoke when it burns, and resists the spread of flame. The tests behind them are IEC 61034-2 for the smoke, IEC 60754 for the halogen content, and IEC 60332-3-24 for the flame spread on bunched wiring.
Is it harder to strip and terminate?
Slightly. Cross-linked insulation is tougher than PVC, so a worn stripping tool will leave a ragged edge. A sharp automatic stripper handles it without a problem, and the payoff at the termination is a conductor that will not creep under a screw, because the insulation does not soften at the temperatures a loaded terminal reaches.