Factory-Direct Supply of Certified Wires and Conductors for Diverse Industrial Applications
Single Core 3.8/6.6KV Medium Voltage Unarmoured Cable
Voltage: 3.8/6.6kV (Um=7.2kV)
Conductor: Copper or aluminum, stranded Class 2
Conductor Screen: Extruded semi-conducting XLPE
Insulation: XLPE, 2.5-3.2mm (graduated per cross-section)
Insulation Screen: Extruded semi-conducting XLPE
Metallic Screen: Copper tape, 16-35mm²
Outer Sheath: PVC or MDPE (LSZH per BS 7835)
Product Overview
Single Core 3.8/6.6kV (Um=7.2kV) Medium Voltage Unarmoured Cable is an XLPE-insulated, copper tape screened cable for the lowest commercially standardised MV voltage class. Unlike higher MV classes which serve distribution networks, 3.8/6.6kV is predominantly a generation and large motor voltage — it is the standard three-phase voltage at which generators rated approximately 2MW and above deliver power to their step-up transformers, and at which the largest industrial motors (pumps, compressors, mills, crushers) operate. The insulation thickness varies by conductor size (2.5mm to 3.2mm), reflecting the IEC 60502-2 allowance for incremental insulation at this lowest MV tier. This cable is the critical link between rotating machines and switchgear in power stations, industrial co-generation plants, and large pumping installations.
3.8/6.6kV vs Higher MV Classes: A Different Purpose
Cable Construction
1. Conductor — Copper or aluminium, Class 2
2. Conductor Screen — Extruded semi-conducting XLPE
3. XLPE Insulation — 2.5-3.2mm, 90°C rated
4. Insulation Screen — Extruded semi-conducting XLPE
5. Metallic Screen — Copper tape, 16-35mm²
6. Separation Sheath — PVC bedding
7. Outer Sheath — PVC or MDPE (LSZH option)
Conductor
Copper: stranded Class 2. Aluminium: solid or stranded Class 2 per IEC 60228. Compacted circular for smooth screening interface.
Conductor Screen
Extruded semi-conducting XLPE. Eliminates partial discharge at the strand-to-insulation gap — critical for generator cable reliability under continuous full-load operation.
XLPE Insulation
2.5mm to 3.2mm depending on cross-section. Unlike higher MV classes, insulation thickness increases with conductor size at the 3.8/6.6kV level per IEC 60502-2.
Insulation Screen
Extruded semi-conducting XLPE, bonded and strippable. Controls electrical field distribution at the outer insulation boundary.
Metallic Screen
Copper tape, 16-35mm². Earth fault current path for generator and motor protection schemes. Also acts as moisture barrier.
Separation + Outer Sheath
PVC bedding + PVC or MDPE outer sheath. Unarmoured construction — intended for protected indoor cable trenches, not direct burial.
Technical Characteristics
| Rated Voltage U₀/U (Um) | 3.8/6.6kV (7.2kV maximum system voltage) |
| Nominal Insulation Thickness | 2.5mm (25-185mm²), 2.6mm (240mm²), 2.8mm (300mm²), 3.0mm (400mm²), 3.2mm (500-630mm²) |
| Max. Conductor Temperature | 90°C (continuous), 250°C (short-circuit, max 5s) |
| Min. Bending Radius | 12 × overall diameter |
| Frequency | 50Hz |
| Conductor Types | Copper (Class 2 stranded), Aluminium (solid or Class 2 stranded) |
| Sheath Options | PVC, MDPE, or LSZH (BS 7835) |
| Partial Discharge | <5 pC at 1.73U₀ per IEC 60840 |
Applicable Standards
| Standard | Scope |
|---|---|
| BS 6622 | British standard for XLPE insulated single-core cables 3.8/6.6kV to 19/33kV. 3.8/6.6kV is covered under Part 1. |
| IEC 60502-2 | International standard for extruded cables 6kV-30kV. 3.8/6.6kV is the lowest voltage class in this standard. |
| IEC 60840 | PD testing. Factory testing to <5 pC at 6.6kV (1.73U₀) on every production length before dispatch. |
| BS 7835 | LSZH sheathed cables for indoor installations in power stations and industrial plant rooms. |
| IEC 60228 | Conductors — Class 2 stranded copper and aluminium. |
Technical Specifications — Single Core 3.8/6.6kV
XLPE insulation: graduated by cross-section per IEC 60502-2. Copper tape screen: 16mm² (25-120mm²), 25mm² (150-300mm²), 35mm² (400-630mm²). Unarmoured construction — for indoor and cable duct installation only.
| Cross Section (mm²) | Insulation (mm) | Cu Screen (mm²) | Sheath (mm) | Outer Dia. (mm) | Weight Cu (kg/km) | Weight Al (kg/km) |
|---|---|---|---|---|---|---|
| 1 × 25 | 2.5 | 16 | 1.5 | 20.3 | 750 | 580 |
| 1 × 35 | 2.5 | 16 | 1.6 | 21.3 | 870 | 650 |
| 1 × 50 | 2.5 | 16 | 1.6 | 22.4 | 1,090 | 770 |
| 1 × 70 | 2.5 | 16 | 1.7 | 24.2 | 1,310 | 870 |
| 1 × 95 | 2.5 | 16 | 1.7 | 25.8 | 1,560 | 960 |
| 1 × 120 | 2.5 | 16 | 1.8 | 27.4 | 1,830 | 1,070 |
| 1 × 150 | 2.5 | 25 | 1.8 | 29.1 | 2,130 | 1,190 |
| 1 × 185 | 2.5 | 25 | 1.9 | 30.8 | 2,490 | 1,320 |
| 1 × 240 | 2.6 | 25 | 1.9 | 33.5 | 3,040 | 1,520 |
| 1 × 300 | 2.8 | 25 | 2.0 | 36.1 | 3,650 | 1,770 |
| 1 × 400 | 3.0 | 35 | 2.2 | 40.6 | 4,680 | 2,170 |
| 1 × 500 | 3.2 | 35 | 2.3 | 43.6 | 5,670 | 2,570 |
| 1 × 630 | 3.2 | 35 | 2.4 | 48.8 | 6,980 | 2,990 |
Packaging & Delivery
Export Wooden Drum
Fumigated wooden drums. 3.8/6.6kV cables are the lightest and most compact MV class — maximum length per drum for generator connection projects.
Moisture Protection
Factory-sealed cable ends with heat-shrink caps and desiccant. Generator cables stored in power station warehouses require moisture-proof sealing until termination.
Documentation
PD test certificate, AC voltage test report, conductor resistance measurement, material traceability per BS 6622 / IEC 60502-2.
Typical Applications — 3.8/6.6kV Voltage Class
Generator Connections
Primary application. Gen-set busduct-to-switchgear or generator-to-step-up transformer connections in thermal, hydro, and gas turbine power stations. 6.6kV is the most common generator terminal voltage above 2MW.
Large MV Motor Feeders
6.6kV motors in pumping stations, compressors, mills, and crushers. Dedicated cable from MV switchgear to motor terminals. XLPE handles high starting currents.
Industrial Co-Generation
On-site power generation in refineries, chemical plants, and steel mills. 6.6kV generator cables feed directly into the plant's MV switchgear for self-consumption.
Pumping Stations
Water and wastewater pumping installations. Large 6.6kV pump motors direct-connected to dedicated MV feeders from the utility supply point.
Mining MV Equipment
Crushers, conveyors, and hoists operating at 6.6kV in underground and open-pit mining operations. XLPE insulation resists vibration and load cycling.
Switchgear Interconnection
3.8/6.6kV circuits between generator circuit breakers, auxiliary transformers, and MV switchboards within the same power station building.
Request a Quote
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.