Application & Operating Conditions
BS 6708 Types 506, 512, 518, and 524 are 320/550 V multi-core pliable wire armoured (PWA) control and interlock cables designed for interconnecting large underground mining machine segments, hydraulic roof-support electro-hydraulic manifolds, stage-loader consoles, and remote safety monitoring stations in gassy deep mines and surface mineral plants.
Standardized Core-Count Designation
Type numbers correspond directly to core count: Type 506 (6×1.34 mm²), Type 512 (12×1.34 mm²), Type 518 (18×1.34 mm²), and high-density Type 524 (24×0.93 mm²) for multi-channel machine control.
100% Individually Screened Control Cores
Every control core is wrapped in a composite tinned-copper and nylon braided screen so core-to-core short circuits cannot occur—preventing unintended machine start-up if the cable is crushed.
Matched Gland Diameter on Types 506 & 512
Type 506 uses a heavier 3.5 mm inner rubber sheath so both Type 506 and Type 512 share an identical 14.8–16.8 mm inner bedding diameter and 22.1–23.6 mm overall diameter for unified gland tooling.
Fail-Safe Pilot & Control Integrity: Because all 6 to 24 cores are individually screened in contact with each other (37.3 Ω/km for 3 screens in parallel on Types 506/512/518; 44.7 Ω/km on Type 524), any mechanical penetration forces an immediate core-to-earth fault rather than a hazardous core-to-core phantom control signal.
Cable Construction (BS 6708 Types 506, 512, 518 & 524)
Dual-protected BS 6708 control architecture combining individual composite core screens inside the core bundle with external 7/0.45 mm galvanized steel pliable wire armour between elastomeric inner and outer sheaths.
| Layer / Component | Material & BS 6708 Engineering Specification |
|---|---|
| 1. Conductors | Electrolytic flexible stranded tinned copper wire, IEC 60228 Class 5: 19/0.30 mm (1.34 mm², 1.60 mm dia.) on Types 506/512/518; 19/0.25 mm (0.93 mm², 1.30 mm dia.) on Type 524. |
| 2. Core Insulation | Thin-wall high-dielectric EPR or TPE insulation, 0.4 mm nominal radial thickness, colour/number coded for multi-core circuit termination. |
| 3. Individual Core Screens | Composite tinned copper wire and nylon braided screen applied over every individual control core. |
| 4. Core Lay-Up | All screened cores (6, 12, 18, or 24 cores) laid up in contact with each other so individual metallic braids form a continuous interconnected screen matrix. |
| 5. Inner Sheath / Bedding | Extruded rubber-based bedding compound: 3.5 mm radial thickness (Type 506), 1.8 mm (Type 512), and 1.5 mm (Types 518 & 524). |
| 6. Pliable Wire Armour (PWA) | Galvanized steel pliable wire strand armour (7/0.45 mm) applied helically over the inner rubber bedding (4.50–5.40 Ω/km max DC resistance). |
| 7. Outer Sheath | Heavy-duty black chloroprene (PCP) outer sheath, 1.8 mm nominal radial thickness, resistant to hydraulic fluids, abrasion, mine water, and flame spread. |
BS 6708 Type 506 / 512 / 518 / 524 Cross-Section: Multi-core bundle of individually copper/nylon braided EPR/TPE control cores cushioned inside rubber bedding, 7/0.45 mm galvanized steel pliable armour, and a black PCP outer jacket.
Technical Characteristics
Electrical, voltage-drop, resistance, and mechanical ratings verified to British Standard BS 6708 for 320/550 V multi-core control cables.
| Parameter | BS 6708 Rated Value |
|---|---|
| Reference Standard | BS 6708 (Types 506, 512, 518 & 524 Multi-Core Armoured Control Cables) |
| Rated Voltage (Uo/U) | 320 / 550 V AC |
| Routine AC Test Voltage | 1.5 kV AC |
| Core Sizes & Stranding | Types 506/512/518: 1.34 mm² (19/0.30 mm) | Type 524: 0.93 mm² (19/0.25 mm) |
| Conductor Max. DC Resistance (@ 20 °C) | 15.4 Ω/km (Types 506, 512 & 518) | 22.1 Ω/km (Type 524) |
| Armour Max. DC Resistance (@ 20 °C) | 5.40 Ω/km (Types 506 & 512) | 4.76 Ω/km (Type 518) | 4.50 Ω/km (Type 524) |
| 3 Screens in Parallel Max. DC Res. | 37.3 Ω/km (Types 506, 512 & 518) | 44.7 Ω/km (Type 524) |
| Voltage Drop (1-Ph/DC | 3-Phase) | 34 | 30 mV/A/m (Types 506, 512 & 518); 50 | 43 mV/A/m (Type 524) |
BS 6708 Types 506, 512, 518 & 524 Complete Specification Tables
Complete verified BS 6708 dimensional, armour, weight, ampacity, DC resistance, and voltage-drop data across all four control cable configurations.
1. Core, Inner Sheath, Pliable Armour & Overall Dimensions (Types 506–524)
| BS 6708 Type | Cores × Area (mm²) | Stranding (No./mm) | Cond. Dia. (mm) | Insul. Thick. (mm) | Inner Sheath (mm) | Inner Sheath Dia. (mm) | Armour Size (No./mm) | Outer Sheath (mm) | Min. OD (mm) | Max. OD (mm) |
|---|---|---|---|---|---|---|---|---|---|---|
| Type 506 | 6×1.34 | 19/0.30 | 1.60 | 0.4 | 3.5 | 14.8 – 16.8 | 7/0.45 | 1.8 | 22.1 | 23.6 |
| Type 512 | 12×1.34 | 19/0.30 | 1.60 | 0.4 | 1.8 | 14.8 – 16.8 | 7/0.45 | 1.8 | 22.1 | 23.6 |
| Type 518 | 18×1.34 | 19/0.30 | 1.60 | 0.4 | 1.5 | 16.5 – 18.5 | 7/0.45 | 1.8 | 22.8 | 25.3 |
| Type 524 | 24×0.93 | 19/0.25 | 1.30 | 0.4 | 1.5 | 17.9 – 19.9 | 7/0.45 | 1.8 | 24.2 | 26.7 |
2. Mechanical Weights, Current Ratings, DC Resistance & Voltage Drop
| BS 6708 Type | Cores × Area (mm²) | Min. Bend Radius (mm) | Approx. Weight (kg/km) | Copper Weight (kg/km) | Current @ 25 °C (A) | Cond. DC Res. (Ω/km) | Armour DC Res. (Ω/km) | 3 Screens Parallel (Ω/km) | 1-Ph / DC Drop (mV/A/m) | 3-Ph Drop (mV/A/m) |
|---|---|---|---|---|---|---|---|---|---|---|
| Type 506 | 6×1.34 | 236 | 1020 | 150 | 16 | 15.4 | 5.40 | 37.3 | 34 | 30 |
| Type 512 | 12×1.34 | 236 | 1200 | 300 | 13 | 15.4 | 5.40 | 37.3 | 34 | 30 |
| Type 518 | 18×1.34 | 253 | 1400 | 450 | 11 | 15.4 | 4.76 | 37.3 | 34 | 30 |
| Type 524 | 24×0.93 | 267 | 1600 | 450 | 8 | 22.1 | 4.50 | 44.7 | 50 | 43 |
Selection Guide: BS 6708 Control, Lighting & Auxiliary Mining Cables
Compare BS 6708 Types 506–524 multi-core control cables against Type 70/71 lighting feeders, Type FS4 flat catenary cables, and Type 43/44 drill cables.
| BS 6708 Model | Core & Pilot Architecture, Earth Design & Primary Duty |
|---|---|
| BS 6708 Type FS4 (640/1100V Flat) | BS 6708 Type FS4 (640/1100V Flat): Flat parallel 4-core geometry (4×2.5 & 4×4 mm²) with tinned copper braided screens on all phase and pilot cores for monorail festoon and overhead catenary loops (100–120 mm bend radius). |
| BS 6708 Type 44 (125/72V Screened Drill) | BS 6708 Type 44 (125/72V Screened Drill): 5×6 mm² handheld drilling machine cable with composite copper/nylon braided screens on 3 phase cores + unscreened pilot & earth cores around an elastomeric cradle. |
| BS 6708 Type 43 (125/72V Conducting Rubber Drill) | BS 6708 Type 43 (125/72V Conducting Rubber Drill): 5×6 mm² metal-braid-free drilling cable with cores separated around a semiconducting elastomeric cradle and 1.5 mm conducting rubber inner sheath for non-fraying flex fatigue resistance. |
| BS 6708 Type 70 & Type 71 (320/550V Armoured) | BS 6708 Type 70 & Type 71 (320/550V Armoured): 4-core (Type 70, 4×4 mm²) and 5-core (Type 71, 5×4 mm²) unscreened EPR power & coalface lighting cables protected by 7/0.45 mm galvanized steel pliable wire armour. |
| BS 6708 Type 506 / 512 / 518 / 524 (320/550V Control) (This Product) | 6-, 12-, 18-core (1.34 mm²) and 24-core (0.93 mm²) individually composite-screened & pliable wire armoured control cables for inter-segment mining machine telemetry and pilot interlocks. |
| BS 6708 Type 7 (640/1100V Trailing) | BS 6708 Type 7 (640/1100V Trailing): Primary 640/1100 V unarmoured coalcutter trailing feeder (16–150 mm²) with 3 composite-screened phase cores, 1 unscreened pilot core, and central bare earth. |
Frequently Asked Questions (FAQ)
Engineering FAQs covering BS 6708 Type 506/512/518/524 core sizing, gland interchangeability, and voltage-drop calculations.
Why do BS 6708 Types 506, 512, and 518 use 1.34 mm² conductors while Type 524 uses 0.93 mm²?
British imperial-to-metric mining control cable standards transitioned from traditional 40/.0076 inch and 19/.012 inch stranding to metric 19/0.30 mm (1.34 mm²) for 6-, 12-, and 18-core control assemblies, and 19/0.25 mm (0.93 mm²) for the 24-core Type 524 so the 24 individually screened cores remain compact (24.2–26.7 mm OD) and flexible.
Why do Type 506 (6-core) and Type 512 (12-core) have the exact same 22.1–23.6 mm outer diameter?
BS 6708 increases the radial thickness of the inner rubber bedding on Type 506 to 3.5 mm (versus 1.8 mm on Type 512) so both cables achieve an identical 14.8–16.8 mm under-armour diameter and 22.1–23.6 mm outer diameter—allowing mines to standardize on a single flameproof control gland size for 6-core and 12-core circuits.
How do I calculate maximum control loop length using the mV/A/m voltage-drop figures?
Multiply the loop current (A) by the single-phase/DC voltage drop factor (34 mV/A/m for Types 506, 512, and 518; 50 mV/A/m for Type 524) and the one-way route length in metres, then divide by 1000 to obtain total loop voltage drop in volts.
Need BS 6708 Type 506, 512, 518 or 524 Control Cable?
Send your required core count (6, 12, 18, or 24 cores), drum lengths, and project specifications for direct TEBAOFLEX factory pricing.
Explore All Mining & Tunneling Cables
