Factory-Direct Supply of Certified Wires and Conductors for Diverse Industrial Applications
Three Core 6/10KV Medium Voltage Unarmored Cable
Voltage: 6/10kV (Um=12kV)
Conductor: Copper or aluminum, compacted circular Class 2
Conductor Screen: Extruded semi-conductive compound (per core)
Insulation: XLPE, 3.4mm per core
Insulation Screen: Extruded semi-conductive compound + Cu tape screen
Assembly: 3 screened cores + filler + binder tape
Outer Sheath: PVC Type ST2, PE, or LSZH (BS 7835)
Product Overview
Three Core 6/10kV (Um=12kV) Medium Voltage Unarmoured Cable is a complete three-phase XLPE-insulated power cable in a single assembly — three individually screened cores laid up together with filler and binder tape, enclosed within a common PVC outer sheath. Unlike single-core MV cables which require the installer to lay three separate cables per circuit, the three-core cable delivers all three phases in a single drum pull. 6/10kV (Um=12kV) is the standardised three-core MV voltage in GB/T 12706 (China) and is also covered under IEC 60502-2 and BS 6622. For applications where installation space or pull count is limited — such as transformer connections, building risers, and underground duct circuits — three-core cable significantly reduces the number of drums, pulls, and cable cleats required.
Single-Core vs Three-Core MV Cables
| Property | Single-Core MV Cable | Three-Core MV Cable |
|---|---|---|
| Cables per 3-Phase Circuit | 3 separate cable pulls | 1 single pull |
| Installation Labour | 3× cable pulling, cleating, terminating | 1× — cuts site labour by ~60% |
| Bend Radius | 12 × OD | 15 × OD (slightly larger due to bundle diameter) |
| Cable Weight (per circuit) | 3 × single-core weight | Slightly less than 3× due to shared sheath |
| Heat Dissipation | Better — each phase separated | Good — adequate for most buried and duct installations |
| Ampacity Derating | Lower derating for grouping | Moderate derating for three-core bundle (pre-calculated in table data) |
| Typical Use | Long underground runs, high-ampacity circuits | Transformer connections, building risers, short-to-medium underground |
Three Core Cable Construction
1. Conductor — Stranded compacted circular copper or aluminium
2. Conductor Screen — Extruded semi-conductive compound
3. Insulation — XLPE, 3.4mm, 90°C rated
4. Insulation Screen — Extruded semi-conductive compound
5. Metallic Screen — Copper tape
6. Binder Tape — Non-hygroscopic
7. Filler — Non-hygroscopic
8. Outer Sheath — PVC (PE or LSZH option)
Technical Characteristics
| Rated Voltage U₀/U (Um) | 6/10kV (12kV maximum system voltage) |
| Insulation Thickness | 3.4mm per core (all cross-sections) |
| Max. Conductor Temperature | 90°C (continuous), 250°C (short-circuit, max 5s) |
| Min. Bending Radius | 15 × overall diameter |
| Core Identification | Red, Yellow, Blue tape between insulation screen and metallic screen |
| Conductor Types | Copper or aluminium, stranded compacted circular Class 2 per IEC 60228 |
| Sheath Options | PVC Type ST2, PE, or LSZH (BS 7835) |
| Partial Discharge | <5 pC at 1.73U₀ per IEC 60840 |
Applicable Standards
| Standard | Scope |
|---|---|
| GB/T 12706.2 | Chinese national standard for power cables with extruded insulation rated 6kV to 35kV. The primary standard for three-core 6/10kV cables in Chinese markets. |
| IEC 60502-2 | International standard for extruded insulation power cables 6kV to 30kV. Three-core 6/10kV is the most common IEC-standard three-core MV cable globally. |
| BS 6622 | British standard for XLPE insulated cables 3.8/6.6kV to 19/33kV. Covers three-core unarmoured configuration. |
| IEC 60840 | PD testing methodology. Each core individually PD-tested and certified. All three cores in the assembly must pass individually. |
| BS 7835 | LSZH sheathed MV cables for fire-sensitive indoor installations. |
| IEC 60228 | Conductors — Class 2 stranded copper and aluminium, compacted circular. |
Technical Specifications — Three Core 6/10kV
XLPE insulation: 3.4mm (all cross-sections). Ampacity values are pre-calculated for the three-core bundled configuration — no additional grouping derating required. Air: 30°C ambient. Soil: 20°C, 2.5 K·m/W, 0.7m depth.
| Cross Section (mm²) | Conductor Dia. (mm) | Insulation (mm) | Sheath (mm) | Overall Dia. (mm) | Weight Cu (kg/km) | Weight Al (kg/km) | Ampacity Air Cu | Al (A) | Ampacity Soil Cu | Al (A) |
|---|---|---|---|---|---|---|---|---|
| 3 × 25 | 6.0 | 3.4 | 2.3 | 40.2 | 1,905 | 1,438 | 120 | 95 | 135 | 105 |
| 3 × 35 | 7.0 | 3.4 | 2.3 | 42.6 | 2,305 | 1,652 | 145 | 115 | 165 | 125 |
| 3 × 50 | 8.4 | 3.4 | 2.4 | 45.8 | 2,884 | 1,952 | 175 | 135 | 190 | 150 |
| 3 × 70 | 10.0 | 3.4 | 2.6 | 49.5 | 3,620 | 2,314 | 220 | 170 | 240 | 185 |
| 3 × 95 | 11.5 | 3.4 | 2.7 | 52.9 | 4,491 | 2,719 | 265 | 205 | 285 | 220 |
| 3 × 120 | 13.0 | 3.4 | 2.8 | 56.4 | 5,383 | 3,144 | 305 | 235 | 320 | 250 |
| 3 × 150 | 14.5 | 3.4 | 2.9 | 59.8 | 6,382 | 3,584 | 350 | 270 | 365 | 280 |
| 3 × 185 | 16.2 | 3.4 | 3.0 | 63.7 | 7,571 | 4,120 | 395 | 310 | 410 | 320 |
| 3 × 240 | 18.4 | 3.4 | 3.2 | 68.8 | 9,342 | 4,865 | 470 | 370 | 480 | 375 |
| 3 × 300 | 20.5 | 3.4 | 3.3 | 73.6 | 11,271 | 5,675 | 535 | 420 | 540 | 425 |
| 3 × 400 | 23.5 | 3.4 | 3.6 | 80.5 | 14,379 | 6,917 | 610 | 485 | 610 | 485 |
DC Conductor Resistance at 20°C
| Cross Section (mm²) | Copper (Ω/km) | Aluminium (Ω/km) | Cu Short-Circuit (1s, kA) | Al Short-Circuit (1s, kA) |
|---|---|---|---|---|
| 25 | 0.727 | 1.20 | 3.69 | 2.42 |
| 35 | 0.524 | 0.868 | 5.15 | 3.37 |
| 50 | 0.387 | 0.641 | 7.31 | 4.79 |
| 70 | 0.268 | 0.443 | 10.2 | 6.68 |
| 95 | 0.193 | 0.320 | 13.8 | 9.03 |
| 120 | 0.153 | 0.253 | 17.4 | 11.4 |
| 150 | 0.124 | 0.206 | 21.7 | 14.2 |
| 185 | 0.0991 | 0.164 | 26.7 | 17.5 |
| 240 | 0.0754 | 0.125 | 34.6 | 22.6 |
| 300 | 0.0601 | 0.100 | 43.1 | 28.2 |
| 400 | 0.0470 | 0.0778 | 57.4 | 37.65 |
Packaging & Delivery
Export Wooden Drum
Heavy fumigated wooden drums. Three-core cables are heavier and larger in diameter than single-core — drum flange diameter ≥20× cable OD.
Moisture Protection
Factory-sealed cable ends with dual-layer heat-shrink caps and desiccant. Three-core cables require sealing on all three cores plus the overall sheath end.
Documentation
Individual core PD test certificates, core-to-core voltage test report, conductor resistance measurement per BS 6622 / IEC 60502-2.
Typical Applications — Three Core 6/10kV
Transformer Connections
Primary application. Single-cable connection from switchgear to MV/LV transformer — one pull replaces three single-core pulls. Standard for packaged substations.
Underground Distribution Circuits
Short-to-medium underground 6/10kV circuits in industrial parks, commercial developments, and utility networks where a single three-phase cable is preferred.
Building MV Risers
Vertical riser cables in multi-story buildings. Three-core cable simplifies riser cleating and requires one-third the cable support structure of three single-core cables.
Chinese GB/T Standard Projects
6/10kV three-core is the default MV cable in Chinese building codes. GB/T 12706.2 certification required for all domestic Chinese infrastructure tenders.
Industrial Site Distribution
Factory MV ring mains connecting switchgear to distributed packaged substations. Single three-core cable per circuit reduces installation time on congested cable trays.
MV Motor Feeders (Single Drive)
Dedicated 6/10kV cable from MV switchgear to a single large motor. Three-core cable provides all three phases in one termination gland at the motor junction box.
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Frequently Asked Questions
As a factory, we offer flexible MOQ depending on the cable type. For standard stock items, MOQ is low; for customized specifications, please contact our sales team for a detailed quote.
Yes, Qiangli cables are manufactured in compliance with international standards such as UL, CE, TUV, and VDE. We provide full test reports and certificates upon request.
Absolutely. We have a dedicated R&D team that can customize cable structure, material, color, and printing to meet your specific project needs.
For standard products, lead time is usually 7-15 days. For large-scale project orders or customized products, it typically ranges from 20 to 30 days.
Yes, we provide free samples for most standard cables. You only need to cover the international courier costs. Contact us to arrange your sample shipment.