ZR-YJV 4x10mm²+1x6mm² XLPE Copper Cable 0.6/1kV Flame Retardant

Cable Designation & Meaning

ZR-YJV 4×10+1×6 mm² — Cable Specification & Engineering Data

1. Product Overview & Rating Summary. ZR-YJV 4×10+1×6 is a compact, five-core flame-retardant cable designed for low-voltage branch and equipment circuits. It assembles four 10 mm² copper phase conductors around a central 6 mm² copper neutral/PE core, each insulated in XLPE and wrapped in a single ST2 PVC oversheath rated for 0.6/1 kV at 50 Hz. Production and qualification follow GB/T 12706.1 / IEC 60502-1, stranding complies with GB/T 3956, and the ZR marking indicates class ZC flame retardance to GB/T 19666. The finished diameter is approximately 18 mm, with a nominal weight of 625 kg/km in copper construction (340 kg/km for the aluminium YJLV equivalent). Standard supply is 100 m coils or small wooden drums fitted with ≥ Ø 800 mm flanges, each 100 m length weighing about 62.5 kg.

2. Layer-by-Layer Construction (Conductor to Jacket).

3. Electrical Characteristics. The four 10 mm² phase conductors are limited to 1.83 Ω/km at 20 °C, rising to approximately 2.33 Ω/km at the 90 °C operating temperature; the 6 mm² neutral/PE is capped at 3.08 Ω/km. Every production length undergoes a routine 3.5 kV AC power-frequency proof held for five minutes without breakdown. Finished-cable insulation resistance remains above 36.7 MΩ·km, XLPE volume resistivity exceeds 1×10¹² Ω·cm, and typical values include capacitance ≤ 0.55 μF/km, inductance ≈ 0.35 mH/km and 50 Hz AC impedance ≈ 1.85 Ω/km. Under a one-second short circuit each 10 mm² phase can carry approximately 1.15 kA (the 6 mm² neutral on a 0.69 kA basis), calculated from I = k·A/√t with k = 115 for copper/XLPE. Reference loading, with all four phase cores energised, is 65 A in free air at 25 °C and 55 A directly buried at 25 °C — engineering estimates for small-section 4+1 cables; verify against the manufacturer's test certificate.

Electrical Parameters

Cable Parameters

Cable Cross Section Structure

4. Thermal Response & Flame Performance. XLPE supports a continuous conductor temperature of 90 °C and a short-circuit peak of 250 °C for durations up to five seconds. The cable is rated for service ambients between −20 and +45 °C, should not be laid below 0 °C without pre-warming, and uses 25 °C as the reference soil temperature for buried ratings. Flame behaviour meets class ZC of GB/T 19666, proven by both the single-cable vertical test (GB/T 18380.12) and the category-C bunched test (GB/T 18380.35) with char height limited to 2.5 m. The PVC jacket is halogenated and will produce smoke and acid gas in a fire; projects requiring low-smoke zero-halogen performance must specify WDZ-YJY.

5. Installation Practice & Handling. Bends must not fall below 15 times the actual outer diameter — approximately 270 mm for this size. Prior to first energisation, apply the DC site withstand at 4U0 = 2.4 kV for 15 minutes in line with Q/GDW 13244.1-2018. Drums held in cold storage below 0 °C must be brought up to temperature before uncoiling; pulling tension should be kept within 1600 N. The 65 A (air) and 55 A (buried) references require derating whenever ambient temperature, cable grouping or soil thermal resistivity deviates from reference conditions. Crimp lugs, glands and heat-shrink termination kits must be selected for the 3.8 mm phase core, 3.0 mm neutral core and ≈ 18 mm jacket, and both phase and neutral short-circuit withstand should be coordinated with upstream protective device settings.

6. Typical Service Applications. This cross-section is the workhorse of building and light-industrial distribution: branch circuits feeding sub-panels, equipment power leads, motor connections in the 5–15 kW range, lighting and socket distribution in commercial and residential buildings, control panel feeds, workshop and laboratory circuits, and auxiliary power connections. Approved installation methods include conduit (steel or PVC), cable trunking, tray and indoor ducting, both indoors and in covered outdoor locations. For direct burial or mechanically exposed routing, the steel-tape armoured ZR-YJV22 variant is recommended.

7. Testing & Quality Assurance Regime. Routine tests on every length include phase and neutral DC resistance verification (≤ 1.83 / 3.08 Ω/km at 20 °C), the 3.5 kV AC / 5 min withstand, conductor continuity across all five cores and dimensional inspection covering phase insulation ≥ 1.0 mm, neutral insulation ≥ 0.7 mm, sheath ≥ 1.4 mm and overall diameter ≈ 18 mm. Sample and type tests comprise the XLPE hot-set trial at 200 ± 3 °C for 15 minutes under 0.2 MPa (load elongation ≤ 175 %, permanent set ≤ 15 %), XLPE tensile ≥ 12.5 MPa with elongation ≥ 200 %, PVC sheath tensile ≥ 10 MPa with elongation ≥ 125 %, PVC thermal stability ≥ 200 minutes at 200 °C, single-cable and category-C bunched flame trials, and bending assessment. Commissioning on site requires insulation-resistance measurement, the DC 2.4 kV / 15 min withstand and positive L1/L2/L3/N/PE identification before switching. A factory test certificate accompanies each drum.

Flame Retardant Parameters

Insulation Parameters

8. Standards & Conformity. Design and production are governed by GB/T 12706.1 and IEC 60502-1 for 0.6/1 kV extruded-insulation power cables. Conductors satisfy GB/T 3956 / IEC 60228 Class 2 — the 10 mm² phase as seven wires of 1.35 mm with R ≤ 1.83 Ω/km, and the 6 mm² neutral as seven wires of 1.08 mm with R ≤ 3.08 Ω/km. Flame retardance is classified under GB/T 19666 (ZC as the default for the ZR marking) and proven by GB/T 18380.12 and GB/T 18380.35 category C. Installation acceptance follows Q/GDW 13244.1-2018 and GB 50168, while surface marking complies with GB/T 6995. Cables can also be supplied to IEC, BS, DIN, ICEA or JIS requirements on request. Note that the ST2 PVC jacket contains halogen — for tunnels, metro systems, hospitals and other confined public areas, WDZ-YJY is the appropriate specification.

9. Packaging, Storage & Logistics. Standard delivery is 100 m per coil or small wooden drum, with bespoke cut lengths available on request. Each drum carries type, voltage, manufacturer, production year and sequential metre marking per GB/T 6995. Storage should be in dry, covered premises at −20 to +45 °C, shielded from direct sunlight, moisture, oils and sharp objects; coils and drums remain sealed until installation and are stored upright on their flanges rather than flat. In cold conditions, condition drums indoors to ≥ 0 °C before pulling. During transit, coils and drums must be secured against rolling and impact, and the cable must never be dragged across abrasive ground or sharp edges.

10. Procurement Specification. State "ZR-YJV 0.6/1 kV 4×10+1×6" together with the required length or drum arrangement and marking preferences. Specify the flame-retardant class (ZC is standard; ZA or ZB available), jacket colour and any special drum requirements. Always request the factory test certificate to confirm the actual unarmoured diameter (≈ 18 mm), weight (≈ 625 kg/km) and ampacity for the production batch. Where low-smoke zero-halogen or armoured construction is needed, order WDZ-YJY or ZR-YJV22 respectively.

11. Cable Industry FAQ.

• Q1: What distinguishes YJV, ZR-YJV, YJV22 and WDZ-YJY from one another? YJV denotes the base XLPE-insulated PVC-sheathed cable; ZR-YJV adds flame-retardant properties (class ZC by default); YJV22 introduces a steel-tape armour between the assembly and sheath for direct burial and mechanical robustness; WDZ-YJY substitutes a halogen-free, low-smoke sheath for the PVC, intended for enclosed public spaces.
• Q2: What is the meaning of ZA, ZB, ZC and ZD? These are flame-retardant classes defined in GB/T 19666, assessed through the bunched-cable test GB/T 18380.35 at progressively higher fuel loads — ZA is the most demanding, ZD the least. The bare "ZR" marking defaults to ZC; ZA and ZB must be explicitly requested at the order stage.
• Q3: Why is the neutral/PE conductor only 6 mm² when the phases are 10 mm²? In a balanced four-wire circuit the neutral carries primarily unbalance and harmonic current, so GB/T 12706.1 permits a reduced core in the 4+1 construction. If the installation serves substantial single-phase or non-linear, harmonic-generating loads, an equal-section 5-core cable should be considered.
• Q4: When should a 4+1, 5-core equal, or 4-core cable be selected? Choose 4+1 for standard four-wire service with a reduced neutral/PE; 5-core equal (4×A+1×A) where neutral current is expected to approach phase current; plain 4-core for applications where no separate PE conductor is needed in the cable.
• Q5: Why do air and buried current ratings differ, and how are they adjusted? Published figures assume 25 °C air or 25 °C soil at 1.0 K·m/W thermal resistivity with a single circuit. Manufacturer correction factors must be applied for ambient temperature, cable grouping, burial depth and soil resistivity — air factors range from about 1.29 at 20 °C down to 0.91 at 45 °C, and soil factors from 1.04 at 20 °C to 0.87 at 40 °C.
• Q6: Copper or aluminium conductor? Copper (this cable) delivers lower resistance (1.83 versus roughly 3.08 Ω/km at 10 mm²), higher current per mm², superior mechanical strength and more dependable terminations; aluminium (YJLV, ≈ 340 kg/km in this size) costs less and weighs less but demands larger cross-sections and anti-oxidation treatment at every joint.
• Q7: Why can XLPE operate at 90 °C while PVC insulation is limited to 70 °C? The cross-linking process transforms polyethylene into a three-dimensional thermoset network, which raises the continuous conductor rating to 90 °C and the short-circuit withstand to 250 °C — directly boosting the ampacity available from a given copper area.
• Q8: How is the conductor cross-section determined? Selection is governed by (a) full-load current after applying derating factors, (b) permissible voltage drop (typically ≤ 5 % for branch circuits), (c) short-circuit withstand on an I²t basis (1.15 kA·s per phase here), and (d) coordination with overcurrent protective devices; the most stringent criterion controls.
• Q9: Why does finished diameter vary between manufacturers for the same nominal size? Standards mandate minimum insulation and sheath thicknesses together with electrical performance, but not a precise overall diameter. Stranding compaction, filler design and sheath tolerance differ between plants — published 4×10+1×6 figures cluster around 18 mm unarmoured — so the actual measured diameter should always be used when sizing glands, trays and conduits.
• Q10: Which tests confirm acceptability on delivery and before energisation? At delivery, verify the factory test certificate (resistance 1.83/3.08 Ω/km, 3.5 kV/5 min withstand, dimensions ≈ 18 mm), jacket legibility and drum integrity. After installation, complete an insulation-resistance test plus the DC 4U0 = 2.4 kV / 15 min withstand per Q/GDW 13244.1-2018, then confirm L1/L2/L3/N/PE identification before closing the breaker.
• Q11: What service life can be expected? When installed and operated within the stated temperature and voltage limits, XLPE 0.6/1 kV cables are designed for a minimum service life of 30 years; sustained overload, ultraviolet exposure, water ingress through a damaged sheath, or operation above 90 °C will materially reduce that lifespan.