BS 6708 Type 630 & 631 3.8/6.6kV Armoured Mining Power Cable for Excavating and Crushing Equipment with EPR Insulation, Screened Phase Cores, and Heavy-Duty Chloroprene Sheath
APPLICATION
Used for supplying excavating, crushing machines and equipment.
Cable Structure:
CONDUCTOR : Electrolytic, stranded, tinned copper wire IEC 60228 Class 5
INSULATION : EPR
SCREEN : Tinned copper / Nylon braided screen over phase cores. Ground core in Type 631 is not screened.
LAYUP : All cores are laid up in contact with each other.
BEDDING : Rubber based bedding compound.
ARMOUR : Galvanized steel pliable armour.
OUTER SHEATH : Heavy duty chloroprene outer sheath.
Cable Properties: RELATED STANDARDS : BS 6708
RATED VOLTAGE : 3800/6600 V
TEST VOLTAGE : 15 kV
Technical Specifications:
Cross Section | 3×35 | 3×50 | 3×70 | 3×95 | 3×120 | 3×150 | 3×50+35 | 3×70+50 | |
|---|---|---|---|---|---|---|---|---|---|
Phase Conductors | |||||||||
Number and cross section | mm2 | 3×35 | 3×50 | 3×70 | 3×95 | 3×120 | 3×150 | 3×50 | 3×70 |
Insulation thickness | mm | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
Pilot Conductor | |||||||||
Number and cross section | mm2 | – | – | – | – | – | – | 1×35 | 1×50 |
Stranding | mm | – | – | – | – | – | – | 276/0,40 | 396/0,40 |
Conductor diameter | Nom. mm | – | – | – | – | – | – | 8.40 | 10.10 |
Insulation thickness | mm | – | – | – | – | – | – | 5.0 | 5.0 |
Cable details | |||||||||
Radial thickness of inner sheath | mm | 3.8 | 3.8 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
Min. inner sheath diameter | mm | 53.1 | 6.0 | 67.0 | 72.3 | 75.5 | 80.0 | 65.4 | 70.5 |
Max. inner sheath diameter | mm | 56.1 | 60.0 | 67.0 | 72.3 | 75.5 | 80.0 | 69.2 | 74.3 |
Size of armour | mm | 7/0,90 | 7/0,90 | 7/1,25 | 7/1,25 | 7/1,25 | 7/1,25 | 7/0,90 | 7/1,25 |
Outer sheath thickness | mm | 6.0 | 6.3 | 6.8 | 7.3 | 7.6 | 8.0 | 6.9 | 7.4 |
Min. overall diameter | mm | 70.5 | 75.0 | 85.1 | 90.6 | 94.4 | 99.6 | 86.7 | 92.8 |
Max. overall diameter | mm | 74.5 | 79.3 | 84.9 | 94.9 | 98.7 | 103.9 | 91.0 | 97.1 |
Min. bending radius | mm | 894 | 952 | 1.019 | 1.139 | 1.185 | 1.247 | 1.092 | 1.166 |
Appx. cable weight | kg/km | 8.4 | 9.85 | 12.05 | 13.85 | 19.2 | 21.2 | 12.1 | 14.25 |
Copper weight | kg/km | 1.01 | 1.45 | 2.02 | 2.75 | 3.46 | 4.33 | 2.1 | 3.1 |
Electrical details | |||||||||
“Continuous current | A | 135 | 170 | 205 | 250 | 295 | 320 | 170 | 205 |
Max. DC resistance at 20°C | |||||||||
Phase conductors | Ω /km | 0.565 | 0.393 | 0.277 | 0.210 | 0.164 | 0.132 | 0.393 | 0.277 |
Earth conductor | Ω /km | – | – | – | – | – | – | 0.565 | 0.393 |
Armour | Ω /km | 0.76 | 0.71 | 0.46 | 0.43 | 0.41 | 0.39 | 0.45 | 0.42 |
3 screens in parallel connection | Ω /km | 0.10 | 0.88 | 0.72 | 0.78 | 0.62 | 0.67 | 0.45 | 0.42 |
Mining operations demand highly reliable, durable, and safe electrical systems to power heavy machinery such as excavators, crushers, and loaders. The BS 6708 Type 630 and Type 631 3.8/6.6kV armoured mining power cables have emerged as trusted solutions for these challenging environments. But what sets them apart from other mining cables, and why are they particularly suited for South African mining operations?
How Do Type 630 and 631 Compare in Design?
Feature | Type 630 | Type 631 |
|---|---|---|
Ground Core Screening | Screened | Not screened |
Phase Core Screen | Tinned copper/nylon braid | Tinned copper/nylon braid |
Typical Applications | Excavating and crushing machines | Excavating and crushing machines |
Mechanical Protection | Armoured with steel | Armoured with steel |
The main difference lies in the ground core screening, which influences electrical noise performance and fault current handling.
Where Are BS 6708 Type 630 & 631 Cables Used?
These cables are optimized for excavating and crushing equipment, typically found in:
Underground and open-pit mining operations.
Quarrying operations for stone, sand, and gravel.
Heavy-duty industrial crushing plants.
Conveyors and feeders in ore processing facilities.
Why Are They Suitable for South African Mines?
South African mines face extreme mechanical stress, humidity, dust, and chemical exposure. These cables’ armoured construction, EPR insulation, and chloroprene outer sheath ensure they withstand these conditions. A notable example is a platinum mine in Rustenburg, where Type 631 cables powered large-scale crushing equipment for over 5 years without major maintenance issues.
What Are the Typical Mechanical and Electrical Challenges in Mining Applications?
Abrasion: Rocks and machinery can wear outer sheaths. The chloroprene sheath resists these forces.
Mechanical Stress: Excavators and crushers can generate high dynamic loads. Steel armour absorbs this stress.
Electrical Interference: Mining machinery often causes electromagnetic interference; screened phase cores mitigate this.
Temperature and Moisture: EPR insulation performs well under high temperatures and moisture, preventing breakdowns.
How Do Type 630 and 631 Compare to Other BS 6708 Mining Cables?
Feature | Type 630 & 631 | Type 621 | Type 611 |
|---|---|---|---|
Voltage Rating | 3.8/6.6 kV | 3.8/6.6 kV | 6.6/11 kV |
Armour | Galvanized steel | Galvanized steel | Aluminium/Steel |
Insulation | EPR | EPR | EPR or XLPE |
Screened Phase Cores | Yes | No | Yes |
Outer Sheath | Chloroprene | Chloroprene | PVC/Chloroprene |
Applications | Excavators & crushers | Excavators & crushers | Medium voltage feeders |
The main advantages of Type 630/631 are screened phase cores for EMI protection and flexibility for installation in tight or dynamic environments.
Frequently Asked Questions (FAQ)
Can BS 6708 Type 630 & 631 Be Used in Wet Mines?
Yes. The EPR insulation and tin-plated copper conductors resist moisture and corrosion, making them suitable for wet underground environments.
What Is the Maximum Current Carrying Capacity?
The continuous current ratings range from 135A to 320A at 25°C ambient, depending on conductor size.
Can These Cables Be Spliced or Jointed?
Splicing is possible but should be avoided where feasible. Specialized mining cable joints are required to maintain insulation integrity, mechanical protection, and screen continuity.
How Long Can the Cables Last in Harsh Mining Conditions?
With proper installation and maintenance, these cables can last 5–10 years, sometimes longer, depending on mechanical wear and environmental exposure.
Are These Cables Suitable for Portable Mining Machines?
Yes, the cables are flexible enough for semi-portable or mobile machinery, but bending radius and tensile limits must be respected.
How Do I Choose Between Type 630 and Type 631?
Type 630: Ground core is screened, suitable where EMI suppression is critical.
Type 631: Ground core unscreened, suitable for simpler grounding systems or cost-sensitive applications.
The BS 6708 Type 630 & 631 3.8/6.6kV armoured mining power cables are designed for the rigors of heavy-duty mining operations. From EPR insulation and tinned copper conductors to screened phase cores and heavy-duty chloroprene sheaths, they combine electrical reliability, mechanical resilience, and installation flexibility. South African mining operators, in particular, benefit from their durability in harsh underground conditions, ease of installation, and compatibility with heavy excavating and crushing equipment.
By understanding the technical specifications, material composition, electrical performance, and installation requirements, engineers can optimize operational uptime, reduce maintenance costs, and enhance safety in demanding mining environments.
