BS 6708 Type 621 3.8/6.6kV Armoured Mining Power Cable for Excavating and Crushing Equipment with EPR Insulation 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
LAYUP : Cores are laid up over 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 | 4×35 | 4×50 | 4×70 | 4×95 | 4×120 | 4×150 | |
|---|---|---|---|---|---|---|---|
Conductors | |||||||
Number and cross section | mm2 | 4×35 | 4×50 | 4×70 | 4×95 | 4×120 | 4×150 |
Insulation thickness | mm | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
Cable details | |||||||
Radial thickness of inner sheath | mm | 3.8 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
Min. inner sheath diameter | mm | 53.8 | 60.5 | 65.6 | 70.7 | 74.3 | 79.2 |
Max. inner sheath diameter | mm | 56.8 | 63.5 | 69.4 | 74.5 | 78.1 | 83.2 |
Size of armour | mm | 7/0,90 | 7/1,25 | 7/1,25 | 7/1,25 | 7/1,25 | 7/1,25 |
Outer sheath thickness | mm | 6.0 | 6.3 | 7.0 | 7.5 | 7.8 | 8.3 |
Min. overall diameter | mm | 71.2 | 81.0 | 87.1 | 93.2 | 97.4 | 103.3 |
Max. overall diameter | mm | 75.2 | 85.3 | 91.4 | 97.5 | 101.7 | 107.6 |
Min. bending radius | mm | 752 | 853 | 914 | 975 | 1.017 | 1.076 |
Appx. cable weight | kg/km | 8.9 | 11.1 | 13 | 14.05 | 20.6 | 22 |
Copper weight | kg/km | 1.35 | 1.95 | 2.7 | 3.7 | 4.65 | 5.8 |
Electrical details | |||||||
“Continuous current | A | 135 | 170 | 205 | 250 | 295 | 320 |
Max. DC resistance at 20°C | |||||||
Conductors | Ω /km | 0.565 | 0.393 | 0.277 | 0.210 | 0.164 | 0.132 |
Armour | Ω /km | 0.7 | 0.5 | 0.43 | 0.39 | 0.38 | 0.35 |
What Is the BS 6708 Type 621 Mining Cable?
The BS 6708 Type 621 is a high-voltage armoured cable designed to provide power to large mining machines, including excavators, crushers, and other heavy-duty equipment. It complies with the BS 6708 standard, widely recognized in the mining industry for its stringent safety and performance requirements.
Key highlights include:
Rated Voltage: 3.8/6.6 kV
Test Voltage: 15 kV
Conductor Material: Electrolytic, stranded, tinned copper (IEC 60228 Class 5)
Insulation: Ethylene Propylene Rubber (EPR)
Armour: Galvanized steel pliable armour
Outer Sheath: Heavy-duty chloroprene
The cable’s design ensures durability, flexibility, and safety in underground and open-pit mining operations.
What Are the Applications of BS 6708 Type 621 in Mining?
BS 6708 Type 621 is widely used in environments requiring robust mechanical and electrical performance:
Excavating Machines: Powers hydraulic shovels and dragline excavators in open-pit mines.
Crushing Equipment: Supplies crushers and mills that operate continuously under heavy load.
Underground Mining Operations: Suitable for areas where flexibility and abrasion resistance are critical.
Industrial Sites: Can be used in heavy-duty industrial plants with similar mechanical and electrical stress requirements.
South African Case Study:
In a Platinum Mine in Rustenburg, a 4×95 mm² BS 6708 Type 621 cable was deployed to power multiple excavators in the open pit. The cable’s EPR insulation and chloroprene sheath prevented premature wear from abrasive dust and mechanical impacts, and the galvanized steel armour minimized the risk of crushing damage from machinery movement. The installation reduced downtime by 20% compared to older, non-armoured cables.
How Should BS 6708 Type 621 Be Installed?
Proper installation ensures maximum lifespan and safety:
Bending Radius: Maintain the minimum bending radius listed in technical specs (7–10 times the overall diameter) to prevent insulation stress.
Routing: Avoid sharp edges or areas with high mechanical impact. Use cable trays or protective conduit where necessary.
Terminations: Use high-quality connectors compatible with EPR insulation. Ensure the armour is grounded correctly to protect against electrical faults.
Environmental Protection: Although the cable is robust, avoid prolonged exposure to UV if installed above ground.
Tip: Always follow BS 6708 guidelines and local mining safety regulations.
FAQ: Everything You Need to Know About BS 6708 Type 621 Mining Cable
Can BS 6708 Type 621 Cable Handle High Temperatures?
Yes. The EPR insulation can operate in ambient temperatures up to 90°C continuously, and short-term peaks up to 130°C.
Is BS 6708 Type 621 Suitable for Wet Conditions?
Absolutely. The tinned copper conductor resists corrosion, and the chloroprene outer sheath provides water and chemical resistance.
How Does It Compare to Non-Armoured Cables?
Armour offers mechanical protection, preventing crushing and abrasion. Non-armoured cables are prone to damage in mining environments, reducing operational reliability.
Can It Be Used in Explosive Atmospheres?
While robust, BS 6708 Type 621 is not classified as intrinsically safe or flameproof. For explosive environments, additional certification and cable types (e.g., flameproof mining cables) should be considered.
How Long Can BS 6708 Type 621 Last?
With proper installation and maintenance, the cable can last 10–15 years, even under continuous heavy-duty mining operations.
Why Choose BS 6708 Type 621 for Your Mining Operations?
High Power Capacity: Supports large excavators and crushers with rated currents up to 320 A.
Mechanical Durability: Galvanized steel armour and chloroprene sheath protect against abrasion and crushing.
Thermal and Chemical Resistance: EPR insulation ensures stable performance in harsh mining conditions.
Proven Track Record: Widely used in South African mines with real-world case studies demonstrating reliability.
Compliance: Meets BS 6708 standard, ensuring safety and performance verification.
The BS 6708 Type 621 cable is engineered for high-stress mining environments, combining electrical performance with mechanical protection. Its EPR insulation, tinned copper conductors, steel armour, and heavy-duty chloroprene sheath make it ideal for powering excavators and crushing equipment. Whether you operate an open-pit platinum mine in Rustenburg or a large-scale quarry, this cable ensures safety, efficiency, and long-term reliability. By understanding its specifications, installation requirements, and real-world applications, mining operators can make informed decisions, reduce downtime, and improve overall operational safety.
