MGM 115 Type 7M 660/1100V Fully Screened Flexible Mining Cable

MGM 115 Type 7M 660/1100 V flexible mining cable in which all three phase cores and the pilot core carry a tinned copper/nylon braid screen, laid around a bare copper earth, with EPR insulation and a heavy-duty chloroprene sheath.

  • Rated / test voltage660/1100 V / 2.5 kV
  • Phase sizes3×16 to 3×120 mm²
  • Core arrangement3 phase + 1 pilot + 1 earth
  • Screened cores3 phase + pilot
  • ConductorTinned Cu, IEC 60228 Class 5
  • Insulation / sheathEPR / chloroprene
  • ArmourNone (flexible)
  • Current, continuous85 – 295 A at 25 °C
Category:
Product overview

MGM 115 Type 7M is a 660/1100 V flexible trailing cable with three phase cores, one pilot core and one bare copper earth conductor. It is built to the MGM 115 specification of the Turkish Hard Coal Enterprises MGM mining cable series, and it is the fully screened member of the Type 7 family: the pilot core carries the same tinned copper/nylon braid screen as the three phase cores.

The cable supplies excavating and crushing machines and other mobile equipment that is moved while energised. It is intended for deep mines where explosive gases and dust can accumulate, and for surface use. Seven sizes run from 3×16 mm² to 3×120 mm², each with a pilot core of the same cross-section as the phase conductors.

Browse the MGM mining cable category for the other cables in the Turkish hard coal MGM series or download the MGM 115 Type 7M datasheet (PDF).

Application & Features

A trailing cable on a mobile machine is the part of the supply system most likely to be crushed, cut or pulled apart. If a machine runs over the cable, the braid screen around each core is the first metal the damage reaches. Because the screens are bonded to the earth, a fault between a phase and its screen trips the protection before a live conductor is exposed. On Type 7M the pilot core is screened as well, so any damage that reaches the pilot also meets an earthed braid first, and the monitoring circuit is protected in the same way as the power cores.

Type 7M is chosen when the pilot circuit is part of the safety chain, for example earth-continuity monitoring that must trip the supply if the earth path to the machine is broken. It fits excavators, crushers, loaders and similar machines fed from a gate-end box or mobile substation, underground or on the surface. Where a separate unscreened pilot is acceptable, the standard MGM 115 Type 7 is the simpler choice; where several thinner control cores are needed, look at Type 7S.

  • Screened pilot coreThe pilot gets its own tinned copper/nylon braid, so four of the five cores are individually screened.
  • Full-size pilotThe pilot core has the same cross-section as the phase conductors in every size, from 16 mm² to 120 mm².
  • Flexible, non-armouredClass 5 tinned copper, EPR insulation and a chloroprene sheath for cables that are dragged and reeled with the machine.
  • Gassy and dusty workingsDesigned for deep mines where explosive gases and dust can accumulate, and for surface plant; approval is quoted per order.
Continuous miner in an underground salt mine gallery with its flexible supply cable, the kind of mobile machine an MGM 115 Type 7M trailing cable feeds
A continuous miner displayed underground in a visitor mine. Mobile cutting and loading machines like this take their 660/1100 V supply through a flexible screened trailing cable such as MGM 115 Type 7M. Photo: Rosenzweig, CC BY-SA 4.0, via Wikimedia Commons.

Specifications

Values from the current TEBAOFLEX MGM 115 Type 7M datasheet. The final construction is confirmed on the approved datasheet for your order.

Electrical, mechanical and material data

Parameter Value
Rated voltage 660/1100 V
Test voltage 2.5 kV
Conductor Stranded, tinned copper wire, IEC 60228 Class 5
Insulation EPR; ground core is not insulated
Screen Tinned copper / nylon braid over phase and pilot cores
Earth core Bare copper, unscreened
Lay-up Three screened phase cores and one screened pilot core laid in contact with the bare earth conductor
Separator Colored textile tape for core identification
Bedding Rubber-based bedding compound
Outer sheath Heavy-duty chloroprene compound
Core arrangement 3 screened phase cores + 1 screened pilot core + 1 bare copper earth core
Application Excavating, crushing machines and equipment; deep mines where explosive gases and dust can accumulate, and surface use

Technical data: MGM 115 Type 7M

Parameter Unit 3×16+16+16 3×25+16+25 3×35+18+35 3×50+25+50 3×70+35+70 3×95+50+95 3×120+50+120
Phase cores / cross-section mm² 3×16 3×25 3×35 3×50 3×70 3×95 3×120
Phase stranding mm 126/0.40 196/0.40 276/0.40 396/0.40 360/0.50 475/0.50 608/0.50
Phase conductor diameter mm 5.5 6.75 8 9.75 11.6 12.75 15.1
Phase insulation thickness mm 1.5 1.6 1.6 1.7 1.8 2 2.4
Earth core / cross-section mm² 1×16 1×16 1×18 1×25 1×35 1×50 1×50
Earth stranding mm 126/0.40 126/0.40 147/0.40 196/0.40 276/0.40 396/0.40 396/0.40
Earth conductor diameter mm 5.5 5.5 6 6.75 8 9.75 9.75
Pilot core / cross-section mm² 1×16 1×25 1×35 1×50 1×70 1×95 1×120
Pilot stranding mm 126/0.40 196/0.40 276/0.40 396/0.40 360/0.50 475/0.50 608/0.50
Pilot conductor diameter mm 5.5 6.75 8 9.75 11.6 12.75 15.1
Pilot insulation thickness mm 1.5 1.6 1.6 1.7 1.8 2.0 2.4
Continuous current rating at 25 °C A 85 110 135 170 205 250 295
Intermittent current rating at 25 °C A 96 125 150 200 250 310 355
Phase conductor Ω/km 1.24 0.795 0.565 0.393 0.277 0.21 0.164
Pilot conductor Ω/km 1.24 0.795 0.565 0.393 0.277 0.21 0.164
4 screens and earth in parallel Ω/km 0.61 0.40 0.35 0.29 0.18 0.16 0.15
Nom. reactance at 50 Hz Ω/km 0.109 0.107 0.101 0.098 0.095 0.094 0.092
Nom. reactance at 60 Hz Ω/km 0.131 0.128 0.121 0.118 0.114 0.113 0.11
Min. insulation resistance at 20 °C MΩ/km 435 375 325 285 0.26 0.25 250
3-phase voltage drop at full load Ω/km 2.62 1.68 1.2 0.84 0.61 0.47 0.38

Selection note: before you size reels, glands and cable handlers, ask our engineers to confirm the overall diameter, cable weight, minimum bending radius, maximum pulling tension, conductor operating temperature and sheath colour, together with the drum length and any marking your mine requires.

Standards & References

  • Design specificationMGM 115 Type 7M, a flexible trailing cable type in the MGM 115 specification of the Turkish Hard Coal Enterprises MGM mining cable series.
  • Conductor referenceStranded tinned copper conductors to IEC 60228 Class 5 (flexible).
  • Voltage scope660/1100 V rated voltage and 2.5 kV test voltage.
  • ApprovalsMine-authority approvals, type-test reports and marking requirements are confirmed and quoted per order.

Construction

MGM 115 Type 7M is a round, non-armoured five-core cable. Three screened phase cores and one screened pilot core are laid up in contact with a bare copper earth conductor, so every braid screen touches the earth along the whole length. A rubber bedding and a heavy-duty chloroprene sheath close the construction.

  • Conductor: stranded tinned copper, IEC 60228 Class 5, from 126/0.40 mm (16 mm²) to 608/0.50 mm (120 mm²); the pilot uses the same stranding as the phase conductors.
  • Insulation: EPR on the phase and pilot cores, 1.5 mm to 2.4 mm depending on size; the earth core is not insulated.
  • Core screens: tinned copper/nylon braid over each of the three phase cores and over the pilot core, four screens in total.
  • Earth core: bare copper, unscreened, 16 mm² to 50 mm², laid in contact with all four screens so that screens and earth act in parallel.
  • Separator: coloured textile tape used for core identification.
  • Bedding: rubber-based bedding compound that fills the lay-up and keeps the cable round.
  • Outer sheath: heavy-duty chloroprene compound against abrasion, tearing and crushing in the roadway.

FAQ

What is MGM 115 Type 7M and how does it differ from the other MGM 115 types?

Type 7M is the MGM 115 flexible cable with three phase cores, one pilot core and one bare earth, in which both the phase cores and the pilot are screened. The standard MGM 115 Type 7 has the same core count but an unscreened pilot, and Type 7S replaces the single pilot with an unscreened unit of three thinner cores. Type 11, Type 14 and Type 16 also have screened phase cores: Type 11 adds one unscreened pilot core, Type 14 one pilot and one earth core, and Type 16 one pilot and two earth cores. None of the MGM 115 types is armoured.

When should I specify Type 7M instead of Type 7?

Choose Type 7M when the pilot carries a protection or earth-continuity monitoring circuit that must trip reliably if the cable is damaged. With a screened pilot, a cut or crush reaches an earthed braid before the pilot conductor, so the fault shows up as an earth fault rather than as a silent change in the monitoring loop. If the pilot only carries a simple control signal and the protection scheme does not require a screened pilot, Type 7 is lighter and simpler to terminate.

Which details are needed for a quotation?

Send the cable type (for example 3×70+35+70), the length per drum and number of drums, the machine and its supply voltage, the pilot or monitoring system you use, any sheath marking, and the mine authority whose approval or test report you need. Because the current datasheet does not list overall diameter or weight for Type 7M, we confirm those with the quotation.

How does Type 7M compare with Type 7S?

Both are 660/1100 V screened trailing cables for the same machines. Type 7M has one pilot core, the same size as a phase conductor and screened, and comes from 3×16 to 3×120 mm². Type 7S keeps the phase screens but has an unscreened pilot unit of three 4 to 10 mm² cores for several control or monitoring signals, and is offered from 3×50 to 3×120 mm². Other MGM types are listed in the MGM mining cable category.

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Quality Assurance

Testing at every stage in our own workshop and laboratory, from incoming copper to the packed drum.

Bare copper wire bobbins inspected before stranding at the TEBAOFLEX factory

Raw Material Inspection

Every batch of copper rod, rubber compound and reinforcing material is checked before it reaches the line.

  • Copper: conductor resistance, elongation and surface condition on incoming rod and drawn wire
  • EPR, CPE, PUR and silicone compounds: hardness, tensile strength, elongation and ageing samples from each mix
  • Suppliers and batch numbers are recorded so every drum can be traced back to its materials
Operator monitoring an extrusion line control panel in the TEBAOFLEX workshop

Manufacturing Process Control

Stranding, insulation extrusion, core assembly and sheathing run under recorded process parameters.

  • Class 5/6 stranding with lay length and tension monitored for trailing and reeling flexibility
  • Continuous-vulcanisation extrusion with wall thickness and spark tests logged on every length
  • Operators sign off each stage before the cable moves to the next machine
3.5 kV voltage withstand test station in the TEBAOFLEX laboratory

Electrical Testing

Finished lengths go through the routine tests required by the referenced VDE, ICEA, IEC or NEK standard.

  • Conductor resistance and insulation resistance on every length
  • Voltage withstand (3.5 kV and higher) and partial-discharge measurement in the shielded HV laboratory
  • Screen and pilot-core continuity checks for mining and reeling constructions
Tensile testing machine for conductor and sheath samples

Mechanical and Ageing Tests

Samples from production are tested for the duty a mining, crane or submersible cable will actually see.

  • Tensile strength and elongation of insulation and sheath before and after ageing
  • Hot-set, ozone, oil-immersion and low-temperature bending tests
  • Constant-temperature water bath for insulation resistance of submersible constructions
Single-cable vertical flame test chamber

Flame Test and Final Inspection

Before packing, the cable is checked against the order and the flame-performance requirement of its standard.

  • Single-cable vertical flame test to IEC 60332-1-2 where specified
  • Metre marking, printing, drum length and appearance inspection
  • Test report and packing list issued with every shipment

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MGM 115 Type 7M 660/1100V Fully Screened Flexible Mining CableGet A Quote