Application & Underground Mining Service
YKGYFtZnyn 3.6/6 kV is a Polish standard medium-voltage steel-tape armoured power cable engineered for primary underground substation interconnectors, main haulage roadway feeders, and inclined drifts up to 45° in underground, open-pit, and strip mines across Polish Upper Silesia and Czech Ostrava-Karvina coalfields.
6 kV Main Haulage & Substation Feeders
Transmits 66 A to 360 A at 3.6/6 kV (11 kV routine AC tested) with 1-second phase short-circuit withstand up to 21.28 kA from shaft-bottom substations to district transformer stations.
Copper Screen + FtZn Crush Armour
Combines a dedicated 10–27 mm² concentric copper-tape metallic screen beneath a PVC separating sheath and helically lapped galvanized steel tape armour (FtZn) for superior radial impact resistance.
Mandatory Red 3.6/6 kV Safety Jacket
High-visibility red special non-flammable PVC outer sheath (OI > 29, PN-EN 60332-3-24) provides immediate underground visual warning of live 6 kV medium-voltage circuits.
45° Inclination Ceiling: Helical galvanized steel tape armour (FtZn) excels against radial rockfall crush along horizontal tunnels and drifts inclined up to 45°, but is not designed to carry vertical suspended cable weight. For steep inclines (> 45°) and vertical shafts up to 90°, specify wire-armoured YKGYFoyn 3.6/6 kV.
Cable Construction & 9-Layer MV Anatomy
Engineered to Polish medium-voltage mining cable architecture (FtZn = galvanized steel tape armour, yn = red OI > 29 PVC outer sheath), YKGYFtZnyn isolates its copper-tape earth screen from the outer galvanized steel tapes via a dedicated PVC separating sheath to prevent bimetallic galvanic corrosion.
| Layer / Component | Material & Polish PN-G / PN-EN Standard Engineering Specification |
|---|---|
| 1. Phase Conductors | Compacted circular multi-wire bare annealed copper conductors complying with PN-EN 60228 Class 2 (10 mm² through 185 mm²). |
| 2. Core Insulation & Marking | Special medium-voltage PVC dielectric in Natural color with printed phase numerals 1, 2, 3, routine tested at 11 kV AC. |
| 3. Central Liner & Core Layup | Three insulated phase cores helically stranded around a shaped central PVC profile liner for mechanical core stability. |
| 4. Filler & Inner Sheath | Interstitial PVC or non-vulcanised rubber filler enclosed by an extruded PVC inner sheath. |
| 5. Common Metallic Screen | Concentric bare copper tape screen (equivalent geometric cross-section /10 mm² up to /27 mm²) for earth-fault current return and radial field containment. |
| 6. Separating Sheath | Moulded extruded PVC or lapped special PVC tape barrier isolating the copper screen from the steel armour against wet-mine galvanic corrosion. |
| 7. Armour (FtZn) | Double helically applied galvanized steel tapes providing high radial crush and pick-impact protection on horizontal and ≤ 45° inclined roadways. |
| 8. Outer Sheath | Red special non-flammable PVC outer sheath (Oxygen Index OI > 29), compliant with PN-EN 60332-1 and bundled vertical flame test PN-EN 60332-3-24 (IEC 60332-3). |
YKGYFtZnyn 3.6/6 kV Cross-Section: Three compacted Class 2 bare copper cores (Natural Special PVC marked 1, 2, 3) stranded around a PVC liner, enclosed by filler/PVC inner sheath, copper-tape common screen, PVC separating sheath, double galvanized steel tape armour (FtZn), and red OI > 29 PVC outer sheath.
Technical Characteristics
YKGYFtZnyn 3.6/6 kV undergoes rigorous 11 kV AC 50 Hz routine dielectric verification and publishes complete zero-sequence earth-capacitance values (0.11–0.16 µF/km) alongside single-phase earth-fault charging currents (0.35–0.51 A/km) required for 6 kV isolated-neutral underground mine relay protection and selective earth-fault tripping studies.
| Parameter | Polish PN-G / PN-EN Standard Rated Value |
|---|---|
| Cable Type Designation | YKGYFtZnyn 3.6/6 kV (Copper-Screened, Galvanized Steel Tape Armoured MV Mining Cable) |
| Rated Voltage (Uo/U) | 3.6/6 kV (6 kV three-phase underground MV distribution) |
| Routine AC Test Voltage | 11 kV AC (50 Hz) |
| Conductor & Screen Range | 3 × 10/10 mm² up to 3 × 185/27 mm² (Compacted Class 2 Cu + Copper Tape Screen) |
| Maximum Route Inclination | Up to 45° from horizontal (brackets, hooks, or roadway trenches) |
| Operating & Short-Circuit Temp. | -30°C to +70°C continuous | +160°C max. short-circuit conductor temperature |
| Minimum Bending Radius | 10 × Overall Cable Diameter (387 mm to 727 mm across range) |
| Flame Retardancy & Jacket Color | Red special PVC with Oxygen Index OI > 29; PN-EN 60332-1 & PN-EN 60332-3-24 (IEC 60332-3) |
Complete 3.6/6 kV Dimensional, Weight & Electrical Schedule (10–185 mm²)
The master medium-voltage engineering table below consolidates nominal outer diameters (38.7–72.7 mm), cable weights (2298–11978 kg/km), maximum 20°C DC conductor resistance, phase inductance, 50 Hz reactance, earth capacitance, earth-fault current per kilometer, 1-second short-circuit kA, and continuous ampacity across all 10 YKGYFtZnyn constructions.
YKGYFtZnyn 3.6/6 kV — Master Mechanical & Electrical Schedule (3×10/10 to 3×185/27 mm²)
| Part Construction (mm²) | Approx. OD (mm) | Cable Weight (kg/km) | Max. DC Res. 20°C (Ω/km) | Inductivity (mH/km) | Reactance 50 Hz (Ω/km) | Earth Cap. (µF/km) | Earth Fault (A/km) | 1s SC Rating (kA) | Current Rating (A) |
|---|---|---|---|---|---|---|---|---|---|
| 3×10/10 | 38.7 | 2298 | 1.83 | 0.400 | 0.126 | 0.11 | 0.35 | 1.15 | 66 |
| 3×16/10 | 41.5 | 2711 | 1.15 | 0.372 | 0.117 | 0.11 | 0.37 | 1.84 | 85 |
| 3×25/14 | 44.5 | 3377 | 0.727 | 0.349 | 0.110 | 0.12 | 0.40 | 2.88 | 110 |
| 3×35/16 | 47.2 | 4241 | 0.524 | 0.338 | 0.106 | 0.13 | 0.41 | 4.03 | 133 |
| 3×50/18 | 51.0 | 5022 | 0.387 | 0.317 | 0.100 | 0.13 | 0.43 | 5.75 | 160 |
| 3×70/18 | 55.0 | 5989 | 0.268 | 0.299 | 0.094 | 0.14 | 0.45 | 8.05 | 197 |
| 3×95/20 | 60.0 | 7240 | 0.193 | 0.286 | 0.090 | 0.15 | 0.47 | 10.93 | 240 |
| 3×120/22 | 63.8 | 8272 | 0.153 | 0.278 | 0.087 | 0.15 | 0.49 | 13.80 | 276 |
| 3×150/24 | 69.3 | 9948 | 0.124 | 0.268 | 0.084 | 0.15 | 0.50 | 17.25 | 314 |
| 3×185/27 | 72.7 | 11978 | 0.0991 | 0.262 | 0.082 | 0.16 | 0.51 | 21.28 | 360 |
3x50/18, 3x50 indicates three 50 mm² compacted Class 2 copper phase conductors and /18 indicates an 18 mm² concentric copper-tape common metallic screen.Polish Armoured Mining Feeder Comparison (YKGYFtZnyn vs YKGYFoyn)
Selecting between galvanized steel tape armoured YKGYFtZnyn and round galvanized steel wire armoured YKGYFoyn is governed strictly by route gradient and axial tension: choose YKGYFtZnyn for economical horizontal/inclined roadways up to 45°, and YKGYFoyn for steep inclines and 90° vertical shafts.
| Polish Armoured Cable Type | Armour Mechanics, Maximum Inclination, Weight & Primary Underground Duty |
|---|---|
| YKGYFtZnyn 3.6/6 kV (This Cable) | Double galvanized steel tape armour (FtZn) + Cu tape screen + red OI > 29 PVC sheath; up to 45° incline; 35–50% lighter than SWA (e.g. 3×50/18 = 5022 kg/km) for main roadway brackets. |
| YKGYFoyn 3.6/6 kV (SWA) | Round galvanized steel wire armour (Fo) + Cu tape screen + red OI > 29 PVC sheath; approved up to 90° vertical mine shafts and boreholes where armour wires support suspended cable weight. |
| YKGYFoyn 0.6/1 kV (SWA) | Low-voltage round galvanized steel wire armour (Fo) + yellow OI > 29 PVC sheath (3×10/6 to 3×120/35 mm²) for 0.6/1 kV vertical shaft feeders up to 90°. |
| YnOGYekm 0.6/1 kV | Flexible Class 5 copper-plastic braid-screened unarmoured cable connecting step-down flameproof transformers to movable 0.6/1 kV face machinery. |
Frequently Asked Questions (FAQ)
Review practical engineering answers to frequent 3.6/6 kV underground network design and installation questions from mine electrical engineers regarding YKGYFtZnyn 45° roadway slope limits, separating-sheath galvanic corrosion protection, standard 6 kV cold-shrink or heat-shrink termination kits, and shaft-cage drum dimensions.
Why is YKGYFtZnyn limited to a 45° inclination angle?
Helically lapped flat steel tapes (FtZn) interlock radially against crushing impacts, but under steep gravitational tension (> 45°) the tape helix can elongate and transfer axial load onto the copper cores. Beyond 45° up to 90° vertical shafts, round steel wire armour (YKGYFoyn) must be used.
Why is there a PVC separating sheath between the copper screen and steel tape armour?
In humid, saline underground mine air, direct contact between bare copper screen tapes and zinc-coated steel armour creates an electrochemical cell that rapidly corrodes the zinc and steel. The PVC separating barrier electrically and chemically isolates both metallic layers until bonded at switchgear earth bars.
Are standard 6 kV indoor/flameproof heat-shrink and cold-shrink terminations compatible?
Yes. Standard 3.6/6 kV 3-core polymeric cable termination kits for unscreened-core / common-copper-tape-screened armoured cables fit YKGYFtZnyn directly, using constant-force springs on the copper tape screen and separate armour earthing clamps on the FtZn steel tapes.
What drum lengths can TEBAOFLEX manufacture for heavy sizes like 3×120/22 or 3×185/27?
Depending on shaft cage dimensions and underground transport clearance, we wind custom single-piece lengths (e.g., 250 m, 300 m, 500 m, or exact substation-to-substation cuts) on reinforced steel-flange or heavy export timber drums.
Planning a 3.6/6 kV Underground Roadway Feeder with YKGYFtZnyn?
Provide your required cross-section (3×10/10 to 3×185/27 mm²), individual drum cut lengths, and mine shaft cage diameter constraints for a tailored factory engineering offer.
Explore All Mining & Tunneling Cables
