MEDIUM VOLTAGE · 3.6 / 6 kV · IEC 60502-2
6 kV XLPE Cable
Industrial plants, mine feeders and substation auxiliary power at the 3.6/6 kV class. Three-core or single-core construction, copper or aluminium conductor, manufactured against IEC 60502-2 with project-specific screen sizing, armour and sheath.
§01 — Cable construction
The reference construction, layer by layer.
At 3.6/6 kV the electrical stress in the XLPE wall is modest, so the wall is only 2.5 mm nominal — the mechanical package (core forming, bedding, armour) dominates the design. Mine and plant feeders on this class usually specify STA armour for direct burial and SWA where tensile load or rodent risk is high. Screen cross-section is selected against the earth-fault current and clearing time of the network, and confirmed against the cable schedule before production.
| # | Layer | Reference detail |
|---|---|---|
| 01 | Conductor | Cu class 2 stranded (RM). Sector-shaped (SM) for 3-core ≥ 185 mm². |
| 02 | Conductor screen | Extruded semiconducting compound, ≤ 0.5 mm nominal thickness. |
| 03 | XLPE insulation | Extruded XLPE, 2.5 mm nominal at 3.6/6 kV (up to 3.2 mm for conductors of 500 mm² and above) per IEC 60502-2, table 6. |
| 04 | Insulation screen | Extruded semiconducting, strippable or bonded per requirement. |
| 05 | Metallic screen | Cu wire screen sized to the network earth-fault current: 16 mm² minimum for conductors up to 120 mm², 25 mm² for 150–300 mm², 35 mm² for 400–630 mm². |
| 06 | Inner sheath | PVC ST2, extruded bedding. |
| 07 | Armour | Double steel tape (STA) for direct burial; SWA for higher tensile load; AWA for single-core. |
| 08 | Serving | Anti-corrosion wrap on certain designs (optional). |
| 09 | Outer sheath | PVC ST2 black; PE or LSZH on request. |
§02 — Technical specifications
Electrical parameters — 3.6 / 6 kV class.
| Conductor (mm² Cu) | Insulation thickness | DC resistance @20 °C (Ω/km) | Indicative current, direct burial 25 °C (A) |
|---|---|---|---|
| 3 × 35 | 2.5 mm | 0.524 | ~170 |
| 3 × 50 | 2.5 mm | 0.387 | ~205 |
| 3 × 70 | 2.5 mm | 0.268 | ~250 |
| 3 × 95 | 2.5 mm | 0.193 | ~300 |
| 3 × 120 | 2.5 mm | 0.153 | ~345 |
| 3 × 150 | 2.5 mm | 0.124 | ~385 |
| 3 × 185 | 2.5 mm | 0.0991 | ~435 |
| 3 × 240 | 2.5 mm | 0.0754 | ~500 |
| 3 × 300 | 2.5 mm | 0.0601 | ~560 |
| 3 × 400 | 2.5 mm | 0.0470 | ~640 |
DC resistance values per IEC 60228. Indicative current: ground 25 °C, soil thermal resistivity 1.5 K·m/W, depth 1.0 m, flat formation — reference only; final ampacity is calculated against your installation conditions. Overall diameter and weight for this voltage class are issued in the project datasheet with the formal offer.
§02B — Worked example · 3.6 / 6 kV
Voltage drop on a 1.2 km mine feeder.
Take a 3 × 95 mm² Cu feeder, 1.2 km, 150 A load current, power factor 0.85. With R = 0.193 Ω/km (IEC 60228) and an assumed reactance of ≈ 0.09 Ω/km for this construction, ΔU ≈ √3 · I · L · (R cos φ + X sin φ) ≈ 65 V — about 1.1% of 6 kV, comfortably inside the usual 5% design limit. We re-run this calculation with your actual route length, formation and conductor material before confirming the cross-section; the final figure is stated in the project datasheet.
§03 — Standards
Standards printed on the sheath and on the drum card.
§04 — Applications
Where 6 kV cable from Lulian is in service.
6 kV plant distribution
Three-core CU/XLPE/CWS/STA/PVC feeding plant switchgear from the main intake substation.
Industrial plant power solutions →Mine feeder circuits
Armoured 6 kV feeders to underground substations; SWA armour for shaft and gallery routes.
Mining and oil & gas cable solutions →Substation auxiliary supply
Station service transformers and auxiliary boards inside 33/6.6 kV substations.
Substation and distribution solutions →Not sure which voltage class your network needs? See all cable applications and sector solutions, or send the system voltage and the earthing method — we confirm the class and the construction in the offer.
§05 — Quality testing
What we test on every drum.
Routine tests run on every drum; sample tests on each batch; type tests on new constructions witnessed by CNAS-accredited third-party labs.
- Conductor DC resistance at 20 °C (routine)
- AC voltage withstand AC 12.5 kV / 5 min (routine)
- Partial discharge ≤ 10 pC at 6.2 kV (1.73 U₀) (sample)
- Insulation thickness & eccentricity (sample)
- Metallic screen cross-section (routine)
- Armour coverage & bedding integrity (routine)
- Sheath thickness + spark test (routine)
- Bending test + voltage after bending (type)
- Impulse voltage 60 kV (type)
§06 — Packaging & delivery
Drums sized for the cable, not for the workshop.
For mine feeders we plan the drum schedule around shaft and gallery headroom — shorter drum lengths and lifting arrangements are agreed at order stage, with the minimum bending radius preserved on every drum. Wooden drums with fumigation marks for export; steel-plywood drums for heavy cross-sections. Cable ends sealed with heat-shrink caps; shipping marks per the buyer’s format.
Standard drum lengths: 500 / 1000 / 1500 / 2000 m. Lead time: 25–35 working days for stocked constructions; 40–55 working days for project-specific builds.
§07 — FAQ
Common questions on 6 kV cable procurement.
What is the U₀/U rating of 6 kV XLPE cable?
3.6 / 6 kV, with Uₘ = 7.2 kV. It covers 6.0 kV and 6.6 kV nominal systems whose maximum operating voltage stays within 7.2 kV. Send the earthing arrangement — solid, resistance or isolated neutral — and we confirm the class and the screen design together.
What conductor cross-sections are available?
Three-core: 25–400 mm². Single-core: 25–630 mm². Copper or aluminium, class 2 stranded; sector-shaped conductors for large 3-core sizes.
Can the cable be direct-buried?
Yes. The armoured construction (STA) with PVC ST2 outer sheath is rated for direct burial. SWA is recommended where tensile load or rodent risk is high.
What is the partial discharge limit?
≤ 10 pC measured at 6.2 kV (1.73 U₀) per IEC 60502-2. PD is measured on every drum and documented on the routine test report.
What routine and type tests are performed?
Routine on every drum: conductor DC resistance, AC voltage withstand AC 12.5 kV / 5 min, sheath spark test. Sample: PD, insulation thickness, screen check. Type: bending + voltage, load cycle, impulse voltage 60 kV.
Can the cable be supplied with LSZH sheath?
Yes, for tunnel, metro, data centre and indoor substation use. Verified against IEC 61034 (smoke density) and IEC 60754 (acid gas).
Is the 6 kV cable suitable for a 6.6 kV system?
Yes. A 6.6 kV nominal system has a phase-to-earth voltage of 3.81 kV and a maximum operating voltage below the 7.2 kV ceiling of the 3.6/6 class. We confirm the assignment against your earth-fault factor before order confirmation.
Send the cable schedule. We confirm the construction in 24 hours.
Share voltage class, conductor material & size, core count, armour, sheath, installation method, total length and drum preference.
§08 — Related
Other voltage classes & adjacent products.
Send an enquiry
Request a quote
Three fields. A technical reply within 24 hours.