Mine Borehole & Shaft Self-Supporting Armoured Drop Cable (0.6/1–15 kV)
Heavy-duty self-supporting galvanized steel wire armoured (SWA / DWA) mine borehole and vertical shaft power feeder cables rated from 0.6/1 kV through 3.6/6 kV, 6/10 kV and 8.7/15 kV. Engineered with Class 2 or Class 5 copper conductors, +90 °C XLPE or HEPR/EPR insulation, metallic copper screens on medium-voltage grades, high-tensile galvanized round steel wire armour and a flame-retardant PVC, CPE or LSZH outer sheath for long vertical drops.
Mine borehole and vertical shaft armoured drop cables transmit main feeder power from surface substations directly down drilled boreholes, ventilation raises and vertical mine shafts to underground distribution levels. Unlike horizontal gallery cables, a vertical drop cable must support its own suspended mass over hundreds of metres without transferring tensile strain to the copper phase conductors.
TEBAOFLEX engineers self-supporting shaft and borehole cables across 0.6/1 kV (3C+E or 4C), 3.6/6 kV, 6/10 kV and 8.7/15 kV (3C + copper screen + SWA/DWA) configurations. High-tensile galvanized round steel wire armour—applied as a single layer (SWA) for medium vertical drops or a counter-helical double layer (DWA) for deep shafts—is calculated with a minimum 5:1 tensile safety factor against the total suspended cable weight.
Medium-voltage constructions (3.6/6 kV to 8.7/15 kV) incorporate triple-extruded +90 °C XLPE or EPR insulation with individual copper tape/wire phase screens and a water-blocking extruded inner bedding, preventing moisture ingress and longitudinal slippage inside the vertical suspension column. Outer sheaths are supplied in flame-retardant PVC (IEC 60332-3-22 Category A), chlorinated polyethylene (CPE) or halogen-free low-smoke (LSZH) compounds.
Specify the system voltage (0.6/1 kV to 8.7/15 kV), conductor size (25 mm² to 240 mm²), vertical suspension depth, borehole casing inside diameter and suspension clamp method with your enquiry. TEBAOFLEX manufactures continuous vertical drop lengths from a 50 m minimum order quantity with a standard lead time of 7–45 working days.
Explore the mining and tunneling cable range for related configurations.
For adjacent mine borehole drop and armoured underground feeder constructions, compare these specifications: Type MP-GC 15kV Mine Power Feeder Cable (for 15 kV EPR/CPE mine power feeders with ground-check monitoring); Fixed Mining Power Cable — PVC / HEPR, SWA / STA Options (for horizontal tunnel and gallery distribution with PVC or HEPR insulation and SWA/STA armour). Verify vertical suspension height, steel-wire armour breaking load, and system voltage before ordering.
Construction
The representative construction illustrates 6/10 kV 3×95 mm² SWA Mine Borehole & Shaft Armoured Feeder Cable: three circular stranded copper power conductors with inner semiconductive screen, +90 °C XLPE/EPR insulation, outer semiconductive screen and concentric metallic screen, laid up in light-grey water-blocking inner bedding, armoured with a complete ring of heavy galvanized round steel wires (SWA) and protected by a thick black flame-retardant outer sheath.
| Component | Material and construction |
|---|---|
| Power conductors | Three stranded annealed or tinned copper conductors (Class 2 compacted circular or Class 5 flexible per IEC 60228, 25 mm² to 240 mm²). |
| Insulation & semiconductive screens | 0.6/1 kV: +90 °C XLPE or HEPR insulation. 3.6/6–8.7/15 kV: extruded conductor semiconductive screen, +90 °C XLPE or EPR medium-voltage dielectric and extruded insulation semiconductive screen. |
| Metallic screen / earth path | 0.6/1 kV: dedicated 4th earth core or concentric armour earth path. 3.6/6–8.7/15 kV: helically applied copper tape or copper wire screen over each phase core. |
| Anti-slip inner bedding | Extruded high-friction elastomeric or PVC inner bedding locks the cabled cores against core slippage during vertical suspension. |
| Self-supporting wire armour (SWA / DWA) | Heavy galvanized round steel wire armour (2.5 mm to 4.0 mm wire diameter) in single-layer (SWA) or torque-balanced double-layer (DWA) configuration to carry the vertical suspension load. |
| Outer serving / sheath | Heavy-duty black flame-retardant PVC (ST2), CPE elastomer or halogen-free LSZH outer sheath resistant to shaft water, abrasion and chemical corrosion. |
Applications
Calculate the total suspended mass for the vertical borehole or shaft drop length and verify that the galvanized steel wire armour breaking load provides at least a 5:1 safety factor at the top wire-mesh or cone-type borehole support clamp.
- Drilled surface-to-underground mine borehole feeder drops anchored at the surface collar with cone-type wire-armour termination clamps.
- Vertical mine shaft power feeders clamped at shaft buntons or suspended along ventilation shafts.
- Sub-level cave and deep-shaft dewatering pump station feeders requiring moisture-resistant SWA or DWA construction.
- Fixed steep-incline drift and decline ramp feeders subject to rockfall, mine water corrosion and high mechanical tension.
For vertical shaft suspension clamping, borehole riser engineering, and underground feeder routing, consult these resources: Armoured and Static Mining Cable: Fixed Distribution Routes (for static gallery, shaft, and substation feeder selection rules); NTMTWOEU 600/1000 V Underground Mine Hoist Cable (for dynamic 600/1000 V mine hoist and shaft conveyance duty). Confirm intermediate clamping intervals, shaft depth, and short-circuit ratings for your mine layout.
Specifications
| Parameter | Value |
|---|---|
| Rated voltage grades | 0.6/1 kV, 3.6/6 kV, 6/10 kV, 8.7/15 kV |
| Maximum continuous conductor temperature | +90 °C (+250 °C short-circuit, 5 s max.) |
| Armour construction | Galvanized round steel wire armour — Single Wire Armour (SWA) or Double Wire Armour (DWA), tensile strength 340–500 N/mm² or high-tensile 1,100–1,370 N/mm² |
| Vertical suspension design factor | Minimum 5:1 armour breaking-load safety factor relative to suspended cable weight |
| Minimum installation bending radius | 12 × cable outside diameter (0.6/1 kV SWA); 15 × cable outside diameter (3.6/6–8.7/15 kV SWA/DWA) |
| Flame propagation compliance | IEC 60332-1-2 and bunched vertical flame test IEC 60332-3-22 (Category A) |
| Commercial supply terms | Minimum order quantity 50 m; manufacturing lead time 7–45 working days |
| Voltage grade & armour type | Nominal cross-section (mm²) | Nominal insulation thickness (mm) | Armour wire diameter (mm) | Nominal outside diameter (mm) | Approx. weight (kg/km) | Continuous ampacity in air at 30 °C (A) | Max. self-supporting vertical drop at 5:1 SF (m) |
|---|---|---|---|---|---|---|---|
| 0.6/1 kV SWA | 4 × 25 | 1.0 | 2.0 | 28.4 | 1,740 | 127 | 260 |
| 0.6/1 kV SWA | 4 × 35 | 1.0 | 2.0 | 31.2 | 2,180 | 157 | 250 |
| 0.6/1 kV SWA | 4 × 50 | 1.0 | 2.5 | 35.8 | 2,980 | 191 | 285 |
| 0.6/1 kV SWA | 4 × 70 | 1.1 | 2.5 | 40.2 | 3,890 | 244 | 270 |
| 0.6/1 kV SWA | 4 × 95 | 1.1 | 2.5 | 44.6 | 4,960 | 296 | 255 |
| 0.6/1 kV SWA | 4 × 120 | 1.2 | 3.15 | 50.4 | 6,480 | 343 | 300 |
| 0.6/1 kV SWA | 4 × 150 | 1.4 | 3.15 | 55.2 | 7,820 | 395 | 285 |
| 3.6/6 kV SWA | 3 × 35 | 2.5 | 2.5 | 39.6 | 2,890 | 162 | 310 |
| 3.6/6 kV SWA | 3 × 50 | 2.5 | 2.5 | 42.8 | 3,480 | 196 | 295 |
| 3.6/6 kV SWA | 3 × 70 | 2.5 | 2.5 | 46.8 | 4,310 | 242 | 280 |
| 3.6/6 kV SWA | 3 × 95 | 2.5 | 3.15 | 52.4 | 5,690 | 293 | 325 |
| 3.6/6 kV SWA | 3 × 120 | 2.5 | 3.15 | 56.0 | 6,680 | 337 | 310 |
| 3.6/6 kV SWA | 3 × 150 | 2.5 | 3.15 | 59.8 | 7,790 | 383 | 295 |
| 6/10 kV SWA | 3 × 35 | 3.4 | 2.5 | 43.6 | 3,280 | 162 | 305 |
| 6/10 kV SWA | 3 × 50 | 3.4 | 2.5 | 46.8 | 3,890 | 196 | 290 |
| 6/10 kV SWA | 3 × 70 | 3.4 | 3.15 | 52.2 | 5,120 | 242 | 330 |
| 6/10 kV SWA | 3 × 95 | 3.4 | 3.15 | 56.4 | 6,180 | 293 | 315 |
| 6/10 kV SWA | 3 × 120 | 3.4 | 3.15 | 60.2 | 7,210 | 337 | 300 |
| 6/10 kV SWA | 3 × 150 | 3.4 | 3.15 | 64.0 | 8,360 | 383 | 285 |
| 6/10 kV DWA | 3 × 185 | 3.4 | 2 × 3.15 | 75.6 | 12,450 | 436 | 540 |
| 6/10 kV DWA | 3 × 240 | 3.4 | 2 × 3.15 | 81.4 | 14,920 | 512 | 510 |
| 8.7/15 kV SWA | 3 × 50 | 4.5 | 3.15 | 53.2 | 4,780 | 196 | 320 |
| 8.7/15 kV SWA | 3 × 70 | 4.5 | 3.15 | 57.2 | 5,710 | 242 | 305 |
| 8.7/15 kV SWA | 3 × 95 | 4.5 | 3.15 | 61.4 | 6,820 | 293 | 290 |
| 8.7/15 kV DWA | 3 × 120 | 4.5 | 2 × 3.15 | 71.8 | 10,380 | 337 | 550 |
| 8.7/15 kV DWA | 3 × 150 | 4.5 | 2 × 3.15 | 75.8 | 11,760 | 383 | 525 |
| 8.7/15 kV DWA | 3 × 185 | 4.5 | 2 × 3.15 | 80.4 | 13,420 | 436 | 500 |
These are the standards this construction is designed and manufactured to (IEC 60502-1, IEC 60502-2, BS 5467 and ICEA S-75-381 vertical drop guidelines).
Maximum self-supporting vertical drop lengths in the table are calculated for standard galvanized steel wire armour with a 5:1 safety factor; deep-shaft DWA constructions with high-tensile steel wire support drops exceeding 600 m.
Always anchor the galvanized steel armour wires directly in a dedicated borehole suspension gland at the top of the drop.
Standards
| Standard or specification | Application |
|---|---|
| IEC 60502-1 & IEC 60502-2 | Power cables with extruded insulation and their accessories for rated voltages from 1 kV up to 30 kV, including round galvanized steel wire armour requirements. |
| BS 5467 / BS 6724 | Electric cables with thermosetting insulation and galvanized steel wire armour for fixed installations and vertical shaft feeders. |
| IEC 60332-3-22 | Tests on electric and optical fibre cables under fire conditions — vertical flame spread of vertically-mounted bunched wires or cables (Category A). |
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