BS 6708 Type 307 1.9/3.3kV Heavy-Duty Screened Mining Cable for Excavating & Crushing Machines

APPLICATION

Used for supplying excavating, crushing machines and equipment.

Cable Structure

CONDUCTOR : Electrolytic, stranded, tinned copper wire IEC 60228 Class 5
INSULATION : EPR (Ground core is not insulated).
SEPERATOR : Colored Textile tape for core identification.
SCREEN : Tinned copper / Nylon braided screen over phase cores. Pilot core is not screened.
LAYUP : All cores are laid up in contact with the bare copper earth conductor.
BEDDING : Rubber based bedding compound.
OUTER SHEATH : Heavy duty chloroprene outer sheath.

Cable Properties

RELATED STANDARDS : BS 6708
RATED VOLTAGE : 1,9/3,3 kV
TEST VOLTAGE : 7,5 kV

Technical Specifications

Cross Section		3×25+25+16	3×35+25+16	3×50+35+25	3×70+50+35	3×95+50+50	3×120+70+70	3×150+70+95
Phase Conductor
Number and cross section	mm2	3×25	3×35	3×50	3×70	3×95	3×120	3×150
Insulation diameter	Nom. mm	13.10	14.70	15.70	17.70	19.10	21.40	23.00
Screen diameter	Nom. mm	15.50	17.10	17.70	19.70	21.10	23.40	25.00
Earth Conductor
Number and cross section	mm2	1×25	1×25	1×35	1×50	1×50	1×70	1×95
Stranding	mm	196/0,40	196/0,40	276/0,40	396/0,40	396/0,40	360/0,50	475/0,50
Conductor diameter	Nom. mm	7.00	7.00	8.50	10.00	10.00	11.70	13.50
Pilot Conductor
Number and cross section	mm2	1×16	1×16	1×25	1×35	1×50	1×70	1×95
Stranding	mm	126/0,40	126/0,40	196/0,40	276/0,40	396/0,40	360/0,50	475/0,50
Conductor diameter	Nom. mm	5.50	5.50	7.00	8.50	10.00	11.70	1.35
Insulation diameter	Nom. mm	11.60	11.60	13.10	14.70	15.70	17.70	19.10
Cable details
Min. overall diameter	mm	47.4	51.6	56.8	62.8	68.9	73.4	75.9
Max. overall diameter	mm	49.9	54.6	59.8	65.8	72.7	77.2	79.7
Min. bending radius	mm	400	440	480	525	580	615	640
Max. pulling tension	kgf	640	830	1.2	1.68	2	2	2
Appx. cable weight	kg/km	4	4.8	6.15	7.6	9.25	11.2	13
Copper weight	kg/km	1.654	1.948	2.666	3.482	4.346	5.45	6
Electrical details
Continuous current rating at 25°C Ambient	A	110	135	170	205	250	295	320
Intermittent current rating at 25°C Ambient	A	130	155	210	255	315	360	385
Max. DC resistance at 20°C
Phase Conductor	Ω /km	0.795	0.565	0.393	0.277	0.21	0.164	0.132
Pilot Conductor	Ω /km	1.24	1.24	0.795	0.565	0.393	0.277	0.21
3 screens and earth in parallel connection	Ω /km	0.5	0.5	0.35	0.35	0.28	0.28	0.14
Nom. reactance at 50Hz	Ω /km	0.125	0.117	0.113	0.108	0.105	0.101	0.098
Nom. reactance at 60Hz	Ω /km	0.15	0.141	0.136	0.129	0.126	0.121	0.118
Min. insulation resistance at 20°C	M Ω /km	1250	1100	950	820	720	660	600
3 phase voltage drop on full load current	mV/A/m	1.69	1.21	0.85	0.61	0.48	0.39	0.32

When mining operations demand reliable medium-voltage power, extreme mechanical durability, and enhanced electrical safety, choosing the right trailing cable becomes critical. One cable type frequently specified for excavators, crushers, and heavy mobile equipment is the BS 6708 Type 307 1.9/3.3kV heavy-duty screened mining cable.

What Is BS 6708 Type 307 Mining Cable Designed For?

BS 6708 Type 307 is a medium-voltage (1.9/3.3kV) screened mining trailing cable designed to supply excavating, crushing, and processing machinery operating under severe mechanical and environmental stress.

It is primarily used where:

Equipment is mobile or semi-mobile
Cables are subject to dragging, bending, vibration, and impact
Enhanced earth fault protection and operator safety are required

Typical applications include:

Excavators and bucket wheel reclaimers
Mobile crushers and screeners
Mineral processing plants
Conveyor head drives and feeders

How Does BS 6708 Type 307 Compare with Other Mining Cables?

Feature	Type 307	Type 43	Type 730
Voltage Level	1.9/3.3 kV	125/72 V	3.8/6.6 kV
Screened Cores	Yes	No	Yes
Typical Equipment	Excavators, crushers	Hand-held tools	Large mining machines
Mechanical Strength	Very High	Medium	Very High
Safety Level	High	Basic	Very High

Type 307 fills the gap between low-voltage tool cables and higher-voltage heavy machine cables, making it extremely versatile.

Where Is BS 6708 Type 307 Used in South Africa? (Case Study)

How Is Type 307 Used in a South African Open-Pit Mine?

In a Northern Cape open-cast iron ore mine, BS 6708 Type 307 cables are used to power:

Mobile jaw crushers
Conveyor transfer stations
Excavating equipment

Why Type 307 was selected:

Compliance with BS 6708 referenced in procurement
Strong resistance to abrasion from sharp rock surfaces
Reliable earth fault protection in wet conditions
Reduced downtime compared with unscreened alternatives

After switching to Type 307, the mine reported:

Fewer cable failures
Improved operator safety
Longer replacement intervals

Frequently Asked Questions (FAQ)

Is BS 6708 Type 307 suitable for continuous trailing applications?

Yes. It is specifically designed for continuous flexing, dragging, and reeling in mining environments.

Why is the pilot core included?

The pilot conductor enables:

Earth continuity monitoring
Interlocking systems
Rapid shutdown in fault conditions

This is essential for modern mining safety systems.

Can BS 6708 Type 307 replace armoured mining cables?

In many mobile applications, yes. Its screened and heavy-duty design provides protection without the stiffness of armour.

Is Type 307 compliant with South African mining requirements?

While BS 6708 is a British standard, Type 307 is widely accepted in South African mines, particularly for imported equipment and EPC projects.

Why Should You Choose BS 6708 Type 307 for Excavating and Crushing Equipment?

BS 6708 Type 307 offers a balanced combination of:

Electrical safety
Mechanical durability
Flexibility
Proven performance in African mining conditions

It is an engineering-driven solution rather than a generic power cable.

How Can You Select the Right BS 6708 Type 307 Cable?

Choosing the correct cable size and configuration requires:

Load calculation
Installation method review
Environmental assessment

👉 Consult with an experienced mining cable supplier or technical engineer to ensure compliance, safety, and long-term reliability for your specific application.