3*70mm2 Medium High Voltage Power Cable 8.5KV 15Kv Armored For Underground

Rated voltage U₀/U

8.5/15 kV​ (conductor-to-earth / conductor-to-conductor)

Highest system voltage Uₘ

17.5 kV​ (per IEC 60038 / IEC 60502-2)

AC withstand (routine)

30.5 kV, 5 min

Lightning impulse (BIL)

95 kV peak

Standard note

The IEC 60502-2 / GB/T 12706​ recognised grade for 15 kV class is 8.7/15 kV​ (U₀=8.7 kV). "8.5/15 kV" appears in some older utility specs or as a rounding/typo; if the project requires strict IEC/GB compliance, confirm whether 8.7/15 kV is acceptable — the cable construction below is identical to the 8.7/15 kV build.

Conductor​

Class 2 compacted stranded annealed copper, 70 mm² → 18/2.32 mm (or equivalent circular compacted), conductor Ø ≈ 9.9 mm​

Conductor screen​

Extruded semi-conductive XLPE-based layer, ≈ 0.6 mm

Insulation​

XLPE (cross-linked polyethylene), nominal thickness 4.5 mm​ (per 8.7/15 kV class, GB/T 12706.2), insulation Ø ≈ 20.2 mm

Insulation screen​

Extruded semi-conductive layer + copper tape screen (≈0.1 mm) helically lapped, bonded to insulation

Core bedding / fill​

PP rope fill, non-hygroscopic, round-up to 3-core assembly

Inner sheath (bedding)​

PVC (90 °C grade, flame-retardant ZC type), nominal ≈ 1.8 mm

Armour​

Double galvanised steel tape, 2 × 0.5 mm (total ≈ 1.0 mm), reverse-lapped

Outer sheath​

PVC, flame-retardant Class C (ZC), black, nominal thickness ≈ 3.1 mm

Overall diameter​

≈ 59–61 mm​ (maker-dependent, 59.1 mm typical)

Weight​

≈ 5 210 – 5 538 kg/km​ (Cu, with steel tape + PVC)

Conductor DC resistance @ 20 °C

≤ 0.268 Ω/km​ (Class 2, GB/T 3956)

Capacitance (approx., L-E)

~0.18 µF/km per core (typical for 15 kV XLPE 70 mm²)

Inductive reactance (3-core, 50 Hz)

~0.11 Ω/km

Continuous conductor temp.

90 °C​ (XLPE)

Short-circuit temp. (max 5 s)

250 °C​

Min. installation temp.

0 °C​ (warm cable if colder)

Max. ambient (design)

40 °C air / 25 °C soil reference

Min. bending radius (3-core armoured)

12 × OD​ ≈ 710 mm​ (GB/T 12706 / maker practice)

Max. pulling tension

≤ 50 N/mm² × 210 mm² (total Cu) ≈ 10.5 kN; use basket grip on armour/sheath, not conductor

Crush resistance

Steel-tape armour resists ≥ 4 kN/10 cm lateral load (direct-burial grade)

Flame retardant

Class C​ per GB/T 18380.3 / GB/T 19666 (ZC) — self-extinguishing, limited spread

Smoke / halogen

Standard PVC sheath: not​ LSZH; emits smoke & HCl. For LSZH use WDZ-YJV22​ instead.

IP (as installed)

IP54 with sealed glands; steel tape + PVC sheath gives moisture/rodent protection

Service life

≥ 30 years at ≤ 90 °C conductor, normal soil/air

Bending

12 D min (~710 mm). Use conduit sweeps; never sharp elbow on armour.

Earthing

Bond steel tape armour + copper screens​ to earth bar at both ends (screen continuity ≤ 0.1 Ω/km equivalent).

Termination

Use 15 kV class cold-shrink or heat-shrink terminations (e.g. 3M QTIII, Raychem RS), strip semi-con screens to precise overlap; stress cone mandatory.

Pulling

Basket grip on outer sheath; max 10 kN; lubricant in ducts.

Jointing

15 kV XLPE joint kit (resin or heat-shrink), screen reconstruction essential.

Pre-energising

1000 V DC megger L-E, L-L ≥ 100 MΩ; VLF 0.1 Hz 15 kV test or 30.5 kV AC 5 min acceptance.

Support

Tray: 600 mm centres horizontal; vertical riser: clamp every 1500 mm due to ~5.3 t/km weight.

Strict IEC/GB 15 kV class

YJV22-8.7/15kV 3×70​ (identical build, standard U₀)

LSZH + flame retardant

WDZ-YJV22 8.7/15 3×70​

Fire-survival emergency feeder

NH-YJV22​ or WDZN-YJV22 8.7/15 3×70​

Aluminium conductor (cost-down)

ZC-YJLV22 8.7/15 3×70​ (≈ 0.443 Ω/km, ~4 280 kg/km)

Single-core armoured

YJV22 1×70​ (but use aluminium tape armour for AC to avoid magnetic loss)

Higher current

3×95 / 3×120​