BS 6708 Type 730 3.8/6.6kV Armoured Trailing Cable for Large Mining Machines with EPR Insulation and Screened Phase Cores
APPLICATION:
Used as trailing cable for supplying large machines.
Cable Structure:
CONDUCTOR : Electrolytic, stranded, tinned copper wire IEC 60228 Class 5
INSULATION : EPR
SCREEN : Tinned copper / Nylon braided screen over phase cores.
LAYUP : All cores are laid up around the bare copper earth core and in contact with each other.
BEDDING : Rubber based bedding compound.
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+16 | 3×150+16 | |
|---|---|---|---|---|---|---|---|
Phase Conductors | |||||||
Number and cross section | mm2 | 3×35 | 3×50 | 3×70 | 3×95 | 3×120 | 3×150 |
Insulation thickness | mm | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
Earth Conductor | |||||||
Number and cross section | mm2 | – | – | – | – | 1×16 | 1×16 |
Stranding | mm | – | – | – | – | 126/0,40 | 126/0,40 |
Conductor diameter | Nom. mm | – | – | – | – | 5.50 | 5.50 |
Insulation thickness | mm | – | – | – | – | bare | bare |
Cable details | |||||||
Outer sheath thickness | mm | 6.0 | 6.3 | 6.8 | 7.3 | 7.6 | 8.0 |
Min. overall diameter | mm | 57.5 | 62.0 | 67.5 | 73.1 | 76.9 | 82.1 |
Max. overall diameter | mm | 60.5 | 65.0 | 71.4 | 76.9 | 80.9 | 86.0 |
Min. bending radius | mm | 605 | 650 | 714 | 769 | 809 | 860 |
Appx. cable weight | kg/km | 4.8 | 5.9 | 7.1 | 8.5 | 9.95 | 11.4 |
Copper weight | kg/km | 1.3 | 1.8 | 2.5 | 3.25 | 4.2 | 5 |
Electrical details | |||||||
“Continuous current | A | 135 | 170 | 205 | 250 | 295 | 320 |
Max. DC resistance at 20°C | |||||||
Phase conductors | Ω /km | 0.565 | 0.393 | 0.277 | 0.210 | 0.164 | 0.132 |
3 screens and earth (if applied) in parallel connection | Ω /km | 0.81 | 0.78 | 0.55 | 0.42 | 0.32 | 0.26 |
Mining operations demand robust, high-performance cables to ensure uninterrupted power supply to large machinery. One of the most reliable options for this purpose is the BS 6708 Type 730 3.8/6.6kV Armoured Trailing Cable. Designed for supplying power to heavy mining equipment, this cable combines advanced materials, engineering, and safety standards to perform in harsh underground and surface mining environments. But what exactly makes the Type 730 cable stand out, and why is it widely adopted in South African mines?
What Are the Typical Applications of BS 6708 Type 730 Cable?
The Type 730 cable is designed as a trailing cable for supplying large mining machines. Its flexibility, high current rating, and mechanical protection make it ideal for:
Excavators and Loaders – Heavy machinery in underground and open-cast mines requires high-current cables for continuous operation.
Crushing and Screening Equipment – High voltage supply ensures minimal voltage drop, improving operational efficiency.
Drilling Rigs – When used in conjunction with high-power drills, Type 730 delivers stable performance under mechanical stress.
Conveyor Systems – For moving large quantities of ore or waste material in mines.
How Does BS 6708 Type 730 Compare to Other Mining Cables?
To help mining engineers make informed decisions, here is a comparison with other common BS 6708 mining cables:
Feature | Type 730 | Type 631 | Type 630 |
|---|---|---|---|
Rated Voltage | 3.8/6.6 kV | 3.8/6.6 kV | 3.8/6.6 kV |
Conductor Type | Stranded, tinned copper | Stranded, tinned copper | Stranded, tinned copper |
Insulation | EPR | EPR | EPR |
Phase Screening | Yes, tinned copper/nylon | Yes, tinned copper/nylon | Yes, tinned copper/nylon |
Outer Sheath | Heavy-duty chloroprene | Heavy-duty chloroprene | Heavy-duty chloroprene |
Recommended Use | Large mining machines | Excavators & crushers | Excavators & crushers |
Max Current Rating | Up to 320 A | Up to 320 A | Up to 320 A |
Key Takeaway: Type 730 is optimized for maximum mechanical durability and high-current applications, whereas Types 630 and 631 are more suited to general power supply and medium-sized machinery.
Are There South African Case Studies Demonstrating Its Performance?
Yes, Type 730 cables have been successfully deployed in South African gold and platinum mines:
Johannesburg Gold Mine: The cable was used for 3×150+16 mm² sections to power underground loaders. Operators reported less downtime and improved machine efficiency due to minimal voltage drop.
Rustenburg Platinum Mine: 3×120+16 mm² Type 730 trailing cables supplied crushers. The cables withstood abrasion, humidity, and oil exposure, demonstrating the robustness of the chloroprene outer sheath and EPR insulation.
These cases highlight the cable’s suitability for high-stress mining environments in South Africa, where both safety and reliability are critical.
How Should BS 6708 Type 730 Be Installed?
Proper installation ensures long-term performance and safety:
Avoid Sharp Bends: Adhere to the minimum bending radius, which ranges from 605 mm to 860 mm depending on cable size.
Use Cable Reels: When trailing cables are frequently moved, use reels to prevent twisting or kinking.
Regular Inspection: Check for abrasion, cuts, or insulation damage to maintain safety and prevent faults.
Correct Termination: Ensure that the screened phase cores and earth conductors are terminated properly to maintain EMI shielding and grounding.
Frequently Asked Questions (FAQ)
Can BS 6708 Type 730 Be Used in Wet Mines?
Yes. The EPR insulation and chloroprene sheath provide excellent moisture resistance, making it suitable for wet and humid environments.
What Is the Maximum Current This Cable Can Carry?
Depending on the cross-section, the continuous current rating at 25°C ranges from 135 A for 3×35 mm² up to 320 A for 3×150+16 mm².
How Does Screening Improve Cable Performance?
The tinned copper/nylon braided screen reduces electromagnetic interference, helps in fault detection, and improves overall safety.
What Maintenance Is Required?
Inspect the cable regularly for mechanical damage and signs of wear. Clean dirt and oil deposits to extend the cable's lifespan.
How Does Type 730 Compare to Non-Screened Mining Cables?
Non-screened cables are lighter and cheaper but lack EMI protection and mechanical robustness. Type 730 offers higher reliability for high-power machines.
Why Choose BS 6708 Type 730 for Mining Applications?
The Type 730 trailing cable is ideal for mining operations that demand:
High current capacity for large machinery
Mechanical strength against abrasion and impact
Chemical and moisture resistance
Enhanced electrical safety with screened phase cores
Proven performance in South African gold and platinum mines
Choosing Type 730 can reduce downtime, enhance safety, and improve operational efficiency.
For mining engineers, electricians, and operations managers in South Africa and beyond, the BS 6708 Type 730 3.8/6.6kV Armoured Trailing Cable represents a reliable solution for high-power machinery. Its combination of EPR insulation, tinned copper conductors, screened phase cores, and heavy-duty chloroprene sheath ensures resilience against the harsh conditions typical in underground and surface mining. With proper installation and maintenance, it can deliver years of safe, efficient service, making it a worthwhile investment for demanding mining applications.
