XLPE Insulated Power Cable: Complete Guide to Types, Standards, Sizing and Installation
What Is an XLPE Insulated Power Cable?
XLPE insulated power cable is a power distribution cable whose conductor is insulated with cross-linked polyethylene. During cross-linking, the long polyethylene chains are chemically bonded into a three-dimensional thermoset network. Unlike thermoplastic PVC or PE, the insulation no longer softens and flows when it heats up, so a XLPE insulated power cable can operate continuously with a conductor temperature of 90 °C and survive a short-circuit peak of 250 °C for up to five seconds.
That single material property explains why XLPE has displaced paper-insulated and PVC-insulated designs in most low-voltage and medium-voltage networks: higher current carrying capacity for the same conductor size, lower dielectric losses, easier jointing and a longer service life.
Cable Construction at a Glance
- Conductor — class 1 solid or class 2 stranded copper or aluminium, manufactured to IEC 60228.
- Conductor screen — semi-conductive tape or extruded layer, required from 6/10 kV upwards to smooth the electric field.
- Insulation — cross-linked polyethylene, normally 0.7 mm for 0.6/1 kV small sizes and up to 4.5 mm for 26/35 kV.
- Bedding and armour — optional inner sheath plus steel tape or steel wire armour for mechanical protection.
- Oversheath — PVC compound ST2 in black, or LSZH compound where fire performance is specified.
Common Types and Designations
Chinese and IEC markets use short designations that compress the whole construction into a few letters. The table below maps the most frequently ordered XLPE insulated power cable types.
| Designation | Construction | Typical application |
|---|---|---|
| YJV | Copper conductor, XLPE insulation, PVC sheath | Indoor, duct and buried distribution, 0.6/1 kV and MV |
| YJLV | Aluminium conductor, XLPE insulation, PVC sheath | Long runs where weight and cost matter |
| YJV22 | Copper, XLPE, steel tape armour, PVC sheath | Direct burial where mechanical damage is likely |
| WDZ-YJV | Copper, XLPE, low smoke zero halogen sheath | Tunnels, stations, data centres, public buildings |
| YJV-8.7/15 kV | Copper, screened XLPE, PVC sheath | Medium-voltage ring mains and substation feeders |
Standards You Should Name in the Enquiry
Buyers who specify the standard avoid 90% of the technical arguments that appear at inspection stage. For XLPE insulated power cable the four documents that matter most are:
- IEC 60502-1 — cables for rated voltages 1 kV and 3 kV.
- IEC 60502-2 — cables for rated voltages 6 kV to 30 kV.
- IEC 60228 — conductor classes and resistance limits.
- GB/T 12706.1 — the Chinese national equivalent widely accepted in Asia and Africa projects.
Other national versions such as BS 7870, VDE 0276 and ICEA S-93-639 remain available on request, together with type test reports from KEMA or TUV laboratories.
Technical Data: 0.6/1 kV Copper XLPE Cable (Excerpt)
Representative values for single-core and three-core YJV cable, copper conductor, 90 °C continuous rating, 30 °C ambient air and 20 °C soil thermal resistivity of 2.5 K·m/W.
| Cross-section | Insulation thickness | Approx. OD | Rating in air | Rating in soil | DC resistance at 20 °C |
|---|---|---|---|---|---|
| 4 mm² | 0.7 mm | 7 mm | 44 A | 56 A | 4.61 Ω/km |
| 25 mm² | 0.9 mm | 10 mm | 130 A | 155 A | 0.727 Ω/km |
| 95 mm² | 1.1 mm | 16 mm | 300 A | 320 A | 0.193 Ω/km |
| 240 mm² | 1.7 mm | 25 mm | 550 A | 540 A | 0.0754 Ω/km |
| 400 mm² | 2.0 mm | 31 mm | 745 A | 695 A | 0.0470 Ω/km |
How to Size an XLPE Cable in Five Steps
- Calculate the design current from the load, diversity factor and power factor.
- Choose a cross-section from the manufacturer rating table and apply derating for ambient temperature, soil resistivity, grouping and burial depth.
- Check voltage drop — normally limited to 5% of nominal voltage between origin and load.
- Verify short-circuit withstand against the protection clearing time using the 250 °C admissible conductor temperature.
- Confirm installation limits — bending radius, pulling tension and duct fill.
The worked example and the full derating factor tables are in our XLPE cable selection guide.
Installation Rules That Prevent Failures
Most XLPE cable failures happen in the first week after installation, not after twenty years of service. Three rules matter:
- Bending radius — 12×D for multi-core 0.6/1 kV cable, 15×(d+D) for three-core MV cable and 20×(d+D) for single-core MV cable.
- No single-core cable in magnetic ducts — the induced eddy currents overheat the sheath; use non-magnetic cable cleats and trefoil formation.
- Voltage test after jointing — a 3.5 kV / 5 min AC test on 0.6/1 kV cable confirms the insulation and terminations before energisation.
If you are still comparing dielectrics, read XLPE vs PVC insulated cable before fixing the specification.
Frequently Asked Questions
What is the difference between YJV and YJLV cable?
Only the conductor: YJV uses copper, YJLV uses aluminium. Aluminium reduces weight and cost but needs one or two sizes larger conductor for the same ampacity.
Can XLPE cable be buried directly in the ground?
Yes, provided the circuit is calculated for soil conditions and the cable is armoured (YJV22) or laid in a sand bed with tiles and warning tape.
What is the maximum conductor temperature of XLPE insulation?
90 °C continuous, 130 °C in emergency overload and 250 °C for a short circuit of five seconds or less.
Which standard should appear on the type test report?
IEC 60502-1 for LV and IEC 60502-2 for MV, tested by a recognised independent laboratory such as KEMA or TUV.
Buying XLPE Insulated Power Cable from a Manufacturer
Shanghai Shenghua Electric Wire & Cable Co., Ltd. has manufactured XLPE insulated power cable since 1997 with 5,000 to 6,000 employees and 70–80% of output exported. The range covers 1.5 mm² to 1000 mm² copper and aluminium conductors, 0.6/1 kV to 26/35 kV, certified to ISO, CE, CCC, KEMA and TUV, with a supply capacity of 100 km per week and a standard delivery time of ten days on wooden drums.
Send us your voltage, cross-section schedule, standard and destination port and we will return a technical offer with type test documents and drum schedule.
