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Mining trailing & reeling cablesBS 6708 Type 6213,800/6,600 V · 4×35–4×150 mm²4 Unscreened + Pliable Armour

BS 6708 Type 621 Armoured Power Cable (3.8/6.6 kV)3,800/6,600 V 4-core unscreened EPR pliable-armoured power cable (4×35–4×150 mm²)

BS 6708 Type 621 3,800/6,600 V (15 kV AC test) pliable-armoured power supply cable with four equal Class 5 tinned copper cores (3 phase + 1 pilot/earth), 5.0 mm EPR insulation, pliable steel wire armour and PCP sheath.

Flame-retardant

Oil-resistant

Water-resistant

Preview size

Order designation: Type 621 · 4 × 70 mm²
Core CSA: 70 mm²
Current (25 °C): 205 A
Max. OD: 91.4 mm
Mass ≈: 13,000 kg/km

Check against my drum All sizes (6)

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Engineering reply in 2 business hoursCut-to-length export drumsEN 10204 3.1 certificate per drum

Rated voltage: 3,800/6,600 V
Core arrangement: 4C + Pliable PWA
Size range: 4×35–4×150 mm²
Ampacity (25 °C): 135–320 A
Operating temp.: −25 to +85 °C
Min. bend radius: 10 × OD (752+)

Typical values for this cable type, based on BS 6708 · IEC 60228 Class 5 — confirmed in the datasheet and quotation for your order.

Application fit

Is BS 6708 Type 621 (3.8/6.6 kV) right for your machine?

6.35/11 kV and 3.8/6.6 kV pliable wire-armoured underground mine roadway feeder cable to BS 6708 Type 621 for district transformers and pantechnicons.

Mine roadway & tunnel wall hangers

Suitable

Primary duty — HV roadway suspension feeding moving longwall district substations.

Fixed installation

Suitable

Armoured HV distribution in mine drifts, tunnels and underground pump stations.

Trailing & towing

With conditions

Pliable wire armour allows periodic handling and extension as the face advances.

Motorised monospiral reel

Not suitable

Pliable wire armour is not rated for continuous motorised reeling drums.

Use (N)TSCGEWÖU MV Reel

Longwall shearer & Bretby handler

Not suitable

HV roadway feeder — cannot be flexed inside coal-face Bretby handlers.

Use BS 6708 Type 307

Typical machines6.6 kV mine roadway power extensionsQuarry primary & secondary crushing plantsLarge surface & underground excavatorsMobile skid-mounted transformer feedersDeep mine pumping & ventilation stationsHeavy industrial 6.6 kV movable plant

Construction

Layer by layer

Four equal-cross-section IEC 60228 Class 5 flexible tinned copper conductors (3 phase cores + 1 pilot/earth core, 35 to 150 mm²) insulated with 5.0 mm nominal EPR are laid up in contact with each other inside a 3.8–5.0 mm rubber inner bedding sheath, armoured with 7/0.90 mm or 7/1.25 mm stranded galvanised steel pliable wire armour and sheathed overall with 6.0–8.3 mm heavy-duty chloroprene (PCP).

Schematic, not to scale — generated from the layer data

#	Layer	Material & reference
1	Phase & pilot/earth conductors (4)	Electrolytic stranded tinned copper wire, IEC 60228 Class 5 (4×35 to 4×150 mm²)IEC 60228 Class 5
2	Medium-voltage EPR insulation	Ethylene propylene rubber (EPR, 5.0 mm nominal radial wall on all sizes, 15 kV AC routine test)BS 6708 (3.8/6.6 kV)
3	Rubber bedding & inner sheath	Rubber-based inner sheath compound (3.8 mm on 4×35 mm²; 5.0 mm on 4×50–4×150 mm²)BS 6708
4	Pliable galvanised steel wire armour	Stranded galvanised steel pliable armour (7/0.90 mm on 4×35 mm²; 7/1.25 mm on 4×50–4×150 mm², 0.35–0.70 Ω/km)BS 6708
5	Heavy-duty chloroprene outer sheath	Heavy-duty flame-retardant polychloroprene (chloroprene / PCP, 6.0 to 8.3 mm radial thickness)BS 6708

BS 6708 Type 621 (4×35–4×150 mm² · Unscreened)

3 unscreened phase cores + 1 unscreened pilot/earth core + pliable galvanised steel wire armour

Screened Alternative: BS 6708 Type 630 / 631

For 3,800/6,600 V pliable-armoured cables with individually copper/nylon braided-screened phase cores, specify Type 630 or Type 631

Technical data

Ratings & operating limits

Typical values: Typical values for this cable type, based on BS 6708 · IEC 60228 Class 5. Values for your order are confirmed in the datasheet and quotation.

Electrical

Rated voltage U0/U: 3,800/6,600 V AC (3.8/6.6 kV) · 15 kV routine AC test voltage
Current rating (25 °C): 135 A (4×35 mm²) to 320 A (4×150 mm²) continuous at 25 °C ambient
Conductor & armour DC resistance: Conductors: 0.565 to 0.132 Ω/km at 20 °C · Pliable steel armour: 0.70 to 0.35 Ω/km at 20 °C

Thermal

Ambient temperature range: −25 °C to +85 °C
Max. conductor temperature: +90 °C continuous EPR operating temperature

Mechanical

Min. bending radius: 752 mm (4×35 mm²) to 1,076 mm (4×150 mm²) (10 × max OD)
Armour & sheaths: 3.8–5.0 mm rubber inner sheath + 7/0.90 or 7/1.25 mm pliable galvanised steel armour + 6.0–8.3 mm heavy-duty chloroprene outer sheath

Resistance

Crush & impact protection: 7-wire stranded galvanised steel pliable wire armour (7/0.90 or 7/1.25 mm) resists rockfall and quarry impact
Flame, oil & environment: 6.0–8.3 mm heavy-duty chloroprene (PCP) outer sheath for deep gassy/dusty mines and surface quarries

Reference standards

Construction standard: BS 6708 (Medium-voltage pliable-armoured mining cables)
Conductor & insulation: IEC 60228 Class 5 tinned copper · 5.0 mm nominal EPR medium-voltage dielectric
Routine voltage test: 15 kV AC routine dielectric test on all four 3.8/6.6 kV cores

Identification

Type designation: BS 6708 Type 621 (3,800/6,600 V · 4 unscreened cores + pliable armour)
Core arrangement: Three phase cores + one pilot/earth core, all unscreened and equal in cross-section (35–150 mm²)

Sizes

6 standard sizes from 4×35 mm² to 4×150 mm² (BS 6708 Type 621 · 3,800/6,600 V)

Complete core, dimensional, mechanical and electrical schedule per BS 6708.

Dimensions & electrical
Designation 4 Cores	Core CSA mm²	Stranding n/mm	Cond. Ø mm	EPR wall mm	Inner wall mm	Inner min Ø mm	Inner max Ø mm	Armour n/mm	Outer wall mm	Min. OD mm	Max. OD mm	Min. bend mm	Current 25 °C A	Cond. DC 20 °C Ω/km	Armour DC 20 °C Ω/km	Cu mass kg/km	Mass ≈ kg/km
Type 621 · 4 × 35 mm²	35	276/0.40	8.40	5.0	3.8	53.8	56.8	7/0.90	6.0	71.2	75.2	752	135	0.565	0.70	1,350	8,900
Type 621 · 4 × 50 mm²	50	396/0.40	10.10	5.0	5.0	60.5	63.5	7/1.25	6.3	81.0	85.3	853	170	0.393	0.50	1,950	11,100
Type 621 · 4 × 70 mm²	70	360/0.50	11.90	5.0	5.0	65.6	69.4	7/1.25	7.0	87.1	91.4	914	205	0.277	0.43	2,700	13,000
Type 621 · 4 × 95 mm²	95	475/0.50	13.90	5.0	5.0	70.7	74.5	7/1.25	7.5	93.2	97.5	975	250	0.210	0.39	3,700	14,050
Type 621 · 4 × 120 mm²	120	608/0.50	15.50	5.0	5.0	74.3	78.1	7/1.25	7.8	97.4	101.7	1,017	295	0.164	0.38	4,650	20,600
Type 621 · 4 × 150 mm²	150	756/0.50	17.20	5.0	5.0	79.2	83.2	7/1.25	8.3	103.3	107.6	1,076	320	0.132	0.35	5,800	22,000

Typical values for this cable type; dimensions and weights for your order are confirmed in the quotation.
All 4 cores (3 phase + 1 pilot/earth) have equal conductor cross-sections and 5.0 mm nominal EPR insulation.
Minimum bending radius is 10 × Maximum Overall Diameter across all sizes.

Reel check

Will it fit your machine?

A first screen using datasheet values. Engineering confirms drum geometry, acceleration and tension with your quotation.

Cable sizeDrum core diameter (mm)

Cable length on drum (m)

Enter your drum core diameterMinimum for this size is about 1,828 mm

Minimum bending radius: 914 mm
Min. drum core diameter: ≈ 1,828 mm
Cable weight on drum: 1,300.0 kg
Outer diameter: 91.4 mm

Indicative only: based on the datasheet outer diameter and 10 × OD bending radius. Current derating for wound layers per DIN VDE 0298-4 is assessed separately.

Quality & approvals

Testing & inspection

Routine tests on every production length, sample and type tests per batch — documented on an EN 10204 3.1 inspection certificate.

ConductorClass 5 stranding
Spark test100 % in-line
Lay-upCores, earth, fillers
SheathingInner, braid / screen, outer
Electrical testsAC voltage, resistance
DimensionsOD, wall thickness
Inspection documents & dispatchDrum & dispatch

Testing & inspection	Test value / reference	Frequency
Routine tests
15 kV AC high-voltage dielectric test	15 kV AC routine voltage withstand test on 3,800/6,600 V 5.0 mm EPR cores per BS 6708	Every shipping drum
Conductor & pliable armour DC resistance	Max. 0.565 to 0.132 Ω/km on Class 5 tinned copper cores; 0.70 to 0.35 Ω/km on pliable GSW armour at 20 °C	Every shipping drum
Sample tests
Chloroprene sheath flame, oil & mechanical test	Heavy-duty PCP outer sheath tested for deep underground and surface mining service per BS 6708	Production batch

Inspection certificate

Issued with every drum, listing the routine test results for that length.

Product approvals

BS 6708 Type 621CE · LVDRoHS · REACH

Company certificates

ISO 9001ISO 14001ISO 45001VDE marks approvalUL / cULCE · LVD / EMC

Marking & supply

Ordering & delivery

Sheath marking

TEBAOFLEX · BS 6708 · TYPE 621 · 3800/6600V · 4 x [mm²]

Delivery form: Export seaworthy fumigated wooden drums matched to 10 × OD bend radius
Lengths: Standard drum lengths or custom cut lengths per mine roadway schedule
Certificate: EN 10204 3.1 factory routine test certificate with every drum
Quote response: Engineering specification and quote within 2 business hours

Technical documents

Downloads

PDFBS 6708 Type 621 Armoured Power Cable (3.8/6.6 kV) – technical datasheet6 sizes · construction, technical data, approvals XLSXBS 6708 Type 621 (3.8/6.6 kV) spec data (Excel)All 6 sizes with dimensions and data, for your BOM or quotation

Revision: 2026-10-20
Updated: 2026-10-20

FAQ

Questions engineers ask first

Not covered here? Send your drawing — an engineer replies within 2 business hours.

How does BS 6708 Type 621 differ from Type 630 and Type 631?

All three are 3,800/6,600 V (3.8/6.6 kV) pliable-armoured mining cables tested at 15 kV AC. Type 621 has four unscreened EPR-insulated cores of equal cross-section (3 phase + 1 pilot/earth, 4×35 to 4×150 mm²). Type 630 has three individually copper/nylon braided-screened phase cores with no fourth core, and Type 631 has three individually screened phase cores plus one unscreened insulated earth core.

Why does Type 621 use 7-wire stranded armour (7/0.90 mm or 7/1.25 mm) instead of single-wire armour?

Pliable wire armour (PWA) is stranded from 7-wire galvanised steel bundles (7/0.90 mm on 4×35 mm²; 7/1.25 mm on 4×50–4×150 mm²) so the cable can be coiled, handled and relocated along advancing mine roadways and quarry benches without kinking or work-hardening.

What is the minimum bending radius for BS 6708 Type 621?

The minimum bending radius is 10 × Maximum Overall Diameter across all sizes, from 752 mm on 4×35 mm² (75.2 mm max OD) to 1,076 mm on 4×150 mm² (107.6 mm max OD).

When should unarmoured BS 6708 Type 730 be selected instead of Type 621?

Select Type 621 for semi-fixed roadway extensions and quarry routes requiring metallic pliable wire armour. For continuously moving 3,800/6,600 V face machines requiring maximum flexibility without steel armour, specify BS 6708 Type 730.

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03Message for our engineers

BS 6708 Type 621 Armoured Power Cable

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