Flame Retardant XLPE Insulated ZR-YJV 3×185mm²+1×95mm² Copper Cable for Power Grid Distribution Projects

Cable Designation & Meaning

ZR-YJV 3×185+1×95 mm² — Cable Specification & Engineering Data

1. Overview & Ratings. ZR-YJV 3×185+1×95 is a high-capacity flame-retarding 3+1-core cable: three 185 mm² copper phase conductors and one 95 mm² copper neutral conductor, XLPE insulation and one ST2 PVC jacket, rated 0.6/1 kV (Um = 1.2 kV), 50 Hz; manufactured and proof-tested to GB/T 12706.1 / IEC 60502-1, stranding to GB/T 3956, ZC fire class to GB/T 19666. Finished diameter ≈ 47.4 mm, mass ≈ 6628 kg/km (Zhongce 3+1 table), supplied in 100 m coils or wooden drums.

2. Construction Stack. Conductor → outer jacket:

3. Electrical Ratings. Phase R ≤ 0.0991 Ω/km (≈ 0.126 Ω/km @ 90 °C), neutral R ≤ 0.193 Ω/km @ 20 °C; factory proof 3.5 kV AC / 5 min; finished-cable insulation resistance ≥ 36.7 MΩ·km; XLPE volume resistivity ≥ 1×10¹² Ω·cm; capacitance ≤ 0.34 μF/km; inductance ≈ 0.24 mH/km; AC impedance ≈ 0.12 Ω/km; short-circuit current ≈ 21.3 kA for 1 s. Reference current (3 phase cores loaded) ≈ 505 A in air @ 30 °C / 435 A buried @ 25 °C — Zhongce 3+1 table basis.

Electrical Parameters

Cable Parameters & Test Parameters

Cable Cross Section Strcuture 

4. Thermal & Fire. 90 °C continuous conductor, 250 °C short-circuit (≤ 5 s); service ambient −20 to +45 °C, minimum laying temp 0 °C; max burial soil temp 25 °C; ZC per GB/T 19666 — GB/T 18380.12 single-cable + GB/T 18380.35 category-C bunched (char ≤ 2.5 m); PVC jacket is halogenated and emits smoke under fire — specify WDZ-YJY for LSZH.

Flame Retardant Characteristics

Insulation Parameters

5. Installation & Care. Minimum bend ≥ 15 × OD (≈ 711 mm); commissioning DC test 4U0 = 2.4 kV / 15 min before first energisation (Q/GDW 13244.1-2018); warm drums below 0 °C before pulling; max pulling tension ≤ 7400 N; derate the 505/435 A references for ambient, grouping and soil; fit lugs and glands sized for the 17.7 mm phase core, 12.6 mm neutral core and 47.4 mm jacket; verify short-circuit rating against protective device settings.

6. Application. Heavy three-phase four-wire distribution, transformer secondaries, large building mains and industrial feeders requiring a dedicated neutral conductor in a single cable (TN-C style) — conduit, tray, trench, duct, trunking, direct burial; indoor or sheltered outdoor. Typical loads include main switchgear incomers, busbar risers in high-rise buildings, pump/compressor stations, data-centre primary feeds and municipal power networks.

7. Testing & Quality Assurance. Every production length undergoes routine tests: phase/neutral DC resistance (≤ 0.0991 / 0.193 Ω/km @ 20 °C), 3.5 kV AC / 5 min power-frequency withstand with no breakdown, conductor continuity and dimensional inspection (phase insulation ≥ 1.6 mm, neutral ≥ 1.1 mm, sheath ≥ 3.0 mm). Sample/type tests cover the XLPE hot-set test (200 ± 3 °C, 15 min, 0.2 MPa — load elongation ≤ 175 %, permanent set ≤ 15 %), XLPE tensile ≥ 12.5 MPa / elongation ≥ 200 %, PVC sheath tensile ≥ 10 MPa / elongation ≥ 125 %, PVC thermal stability ≥ 200 min @ 200 °C, single-cable and category-C bunched flame tests, and bending tests. On site, a DC 2.4 kV / 15 min withstand and phase-identification check are required before energisation. A factory test certificate accompanies each drum.

8. Standards & Compliance. Design and manufacture follow GB/T 12706.1 and IEC 60502-1 (0.6/1 kV extruded-insulation power cables); conductors comply with GB/T 3956 / IEC 60228 Class 2; flame-retardant classification follows GB/T 19666 (ZC default for "ZR"), verified by GB/T 18380.12 (single vertical wire/cable) and GB/T 18380.35 (bunched, category C); installation acceptance follows Q/GDW 13244.1-2018 and GB 50168; surface marking follows GB/T 6995. Cables can also be supplied to IEC, BS, DIN, ICEA or JIS requirements on request. Note: the ST2 PVC jacket contains halogen — for tunnels, metros, hospitals and other enclosed public spaces, specify WDZ-YJY (low-smoke zero-halogen) instead.

9. Packaging, Storage & Transport. Standard supply is 100 m per coil or wooden drum (recommended flange ≥ Ø 1800 mm for this section; net weight ≈ 663 kg per 100 m drum); custom cut lengths are available. Each drum carries type, voltage, manufacturer, year and sequential metre marks per GB/T 6995. Store in dry, covered conditions at −20 to +45 °C, away from direct sunlight, moisture, oils and sharp objects; drums must remain sealed until installation and should stand on their flanges, not lie flat. In cold weather, condition drums indoors to ≥ 0 °C before uncoiling and pulling. Transport with drums secured against rolling and impact; avoid dragging the cable over rough ground or sharp edges.

10. Ordering. ZR-YJV 0.6/1 kV 3×185+1×95 + supply length/drum + surface marking; state flame-retardant class (ZC default; ZA/ZB on request), jacket colour and any special drum requirements; request the manufacturer's factory test certificate to confirm actual OD, weight and ampacity; for LSZH or armoured variants, order WDZ-YJY or ZR-YJV22 respectively.

11. Cable Industry FAQ.

• Q1: What is the difference between YJV, ZR-YJV, YJV22 and WDZ-YJY? YJV is the base XLPE/PVC cable; ZR-YJV adds flame-retardant behaviour (default class ZC); YJV22 adds steel-tape armour over the assembly for direct burial and mechanical protection; WDZ-YJY replaces the PVC jacket with a halogen-free, low-smoke compound for enclosed public spaces.
• Q2: What do ZA / ZB / ZC / ZD mean? They are flame-retardant classes under GB/T 19666, verified by the bunched-cable test GB/T 18380.35 with different fuel loads (A the most stringent, D the least). "ZR" without a letter defaults to ZC; ZA/ZB must be stated when ordering.
• Q3: Why is the neutral core smaller (95 mm² vs 185 mm² phase)? In balanced three-phase circuits the neutral carries mainly unbalance and harmonic current, so GB/T 12706.1 permits a reduced neutral in the 3+1 build. If heavy single-phase or non-linear (harmonic-rich) loads are expected, use an equal-section 4-core cable or a larger neutral.
• Q4: When should I choose 3+1, 4-core equal, or 3+2 cables? 3+1 for general TN-C three-phase four-wire service with a reduced neutral; 4-core equal (3×A+1×A) when neutral current approaches phase current; 3+2 (3 phase + N + PE split) for TN-S systems requiring separate neutral and protective conductors.
• Q5: Why do air and buried ampacities differ, and how are they corrected? Ratings assume 30 °C air or 25 °C soil at 1.0 K·m/W thermal resistivity with one circuit. Apply manufacturer correction factors for ambient temperature, cable grouping, burial depth and soil resistivity; the Zhongce table lists air factors 1.29 (20 °C) down to 0.91 (45 °C) and soil factors 1.04 (20 °C) to 0.87 (40 °C).
• Q6: Copper or aluminium conductor? Copper (this cable) offers lower resistance, higher ampacity per mm², better mechanical strength and more reliable terminations; aluminium (YJLV) is cheaper and lighter but needs larger cross-sections and anti-oxidation treatment at joints.
• Q7: Why is XLPE rated 90 °C while PVC insulation is only 70 °C? Cross-linking turns polyethylene into a thermoset network, raising the continuous conductor temperature to 90 °C and short-circuit tolerance to 250 °C, which directly increases ampacity for the same copper area.
• Q8: How is the conductor cross-section selected? Size against (a) full-load current with derating factors, (b) permissible voltage drop (typically ≤ 5 % for power circuits), (c) short-circuit withstand (I²t), and (d) protection-device coordination; the largest requirement governs.
• Q9: Why do finished-cable diameters vary between manufacturers for the same nominal size? Standards fix minimum insulation/sheath thickness and electrical performance, not exact OD. Stranding compaction, filler design and sheath tolerance differ by plant, so always use the actual measured OD for gland, tray and conduit sizing.
• Q10: What tests prove the cable is acceptable on delivery and before energisation? On delivery: check the factory test certificate (resistance, 3.5 kV/5 min withstand, dimensions), jacket marking and drum condition. After laying: insulation-resistance test plus the DC 4U0 = 2.4 kV / 15 min withstand per Q/GDW 13244.1-2018, then phase/neutral identification before switching on.
• Q11: What is the expected service life? Correctly installed within temperature and voltage limits, XLPE 0.6/1 kV cables are designed for ≥ 30 years of service; prolonged overload, UV exposure, water immersion of damaged jacket, or operation above 90 °C shortens life significantly.