Cables with Aluminium and Copper conductor and polymer insulation are manufactured at Havell's India Ltd. (Cable Works) Alwar. Essentially cables comprise of conductors, insulation, inner-sheath, armour and outersheath. The brief description of the process is mentioned as under:.





Conductor

Havells Cables are available with both aluminum and copper conductors. It is manufactured with solid/Stranded Circular/ Shaped Aluminium / Copper Conductor. Stranding makes Cables flexible and easy to handle while shaping makes them compact.

1)   Circular Conductor :

With one wire in the centre conductor contains 6, 12, 18, 24, 30... wire layers in either unilay or opposite helical directions. The conductor is sized upto 92% compaction.

2)   Shaped Conductors :

In all multicore cables from 16 Sq. mm size, conductors are "shaped". Compaction degree in multicore power cables is upto 92%.

3)   Segmental Conductor :

As a special case Havell's cables of 1600 sq. mm are made up of segmental conductors.

The conductor is manufactured in equal segments and compacted, then laid together. This reduces A.C. losses in the large sized conductor, which are due to skin and proximity effects.

Havells has special construction of conductor to suggest to its customer for meeting their specific need.

Havells Copper conductor cables are of the same construction that of cables with Aluminium conductor except for high tensile strength, superior conductivity, better flexibility and ease of jointing, Copper cables are used in control, instrumentation, winding, submarine, mining and ship wiring etc. etc applications.

All Conductors for Havells Cables are manufactured strictly in accordance with National and International specifications.

National specifications                                IS: 8130
International specification                           IEC :60228 / BS : 6360


Dielectric Insulation

Insulation for Havell's cables is strictly as per National and International specifications.

Havell's cables are designed and manufactured with polymer dielectrics to bear thermal and thermomechanical stresses safely at continuous normal and short circuit temperature conditions.

Havell's cables are available with both thermoplastic & thermo setting insulations.

- PVC Cables          Thermoplastic dielectric
- XLPE Cables         Thermo setting dielectric

Havells PVC cables use PVC compounds that take care of over load and short circuit current with both coarse & fine protection systems.

Havell

Havells cables are friendly during continuous, emergency and short circuit conditions.s XLPE cables use XLPE compound with anti oxidant stabilizers and traces of aromatic polynuclear hydrocarbon. Thus improving electrical treeing characteristics and mechanical strength of insulation.

Though there is no change in basic design of Havell's cables yet the latest manufacturing process gives improved reliability and compactness to cables. The relative thermal expansion during short circuit between dielectric and conductor is therefore limited to minimum both in PVC & XLPE, thus limiting displacement of cores in cables during short circuit.

Insulation for Havells Cables are strictly manufactured and applied over conductor in accordance with National and International specifications:

National Specification
IS : 5831/ IS : 7098

International Specification
BS : 6746/ BS :5467/ IEC : 60502

Screening

XLPE Cables with rated voltage over 3300V shall be provided with conductor and insulation screening as follows :

Conductor : Conductor shall be screened with extruded

Screen : Semiconducting compound as per is :7098 Part 2

Insulation : Insulation screening shall consist of non-metalic

Screen : Part in combination with metalic part. Non metalic part shall consist of either semi conducting compound tape applied hellically or extruded layer of semi conducting compound, applied directly over insulation. Over this, metalic part (copper tape) shall be applied hellically with overlap as per IS:7098 part 2.

To avoid the cavities and voids formation in dielectric particularly on bending operation of cable, perfect bonding of insulation and screening is required. To ensure this Havells applying conductor screen, insulation and insulation screen (non-metalic part) in one operation through tripple extrusion.

Laying Up

Cores are tested on line during production both for physcial and electrical characteristics. Control is observed within tight tolerance limits for dimensions in case pf PVC/XLPE insulation. For multicore cables cores are laid up on our latest laying up machine equipped with sector correction equipment. In case of XLPE insulated cores the same are cured so as to impart the requisite characteristics both electrical and mechanical and then are laid up

Inners Health

Laid up cables are provided with innersheath with high quality of PVC which acts as bedding for steel wire / strip armouring. Wherever required, filler cords are provided to maintain the circularity to laid up cables.

In Havells Cable-polymers used for innersheath are softer than insulation or outer sheath & are compatible with temperature ratings of cables & do not have deleteriocus effect on any other component of cable.

Inner sheath is applied either with extrusion or by wrapping. In Havell's Cables though the inner sheath is closely applied on the laid up cores, same can be stripped with ease without damaging insulation.

The inner sheath dimensions are maintained strictly in accordance with laid down specification .

Specification For PVC Cables IS :1554 (Part-I & II)

For XLPE Cables                     IS : 7098 (Part-I & II)

Armouring

Mechanical protection to the cable is provided with armouring. Havell's single core cables are armoured with Aluminium or Aluminium alloy wire/strips, thus avoiding magnetic hysteresis losses on A. C. System.

Multicore cables are provided with galvanised steel wire/strips.

Havells cables are provided with galvanised wire armouring, where cables are to run vertically and are subjected to stresses.

Havell's Mining cables are armoured with steel wire and tinned copper wires, so as to provide conductivity of armour more than 75% of main conductor of cable. Havells cables armour wires/strips are of low resistivity material and meet the requirements of IS:3975. Havells armoured cables are with almost 95% armour coverage.

Outer Sheath

All Havells Cables are provided with PVC/polymer outer sheath.

Havells Cables are manufactured with various characteristics of sheathing compounds.

General purpose sheathing Compound ST1













Flame Retartant Compound (FR) to EIL Specn.

Ultra Voilet Radiations Resistance Compound to ASTM G-53.

Anti Rodent and Anti Termite Compound.

PVC compounds used for Havell's Cables are of various grades to meet specifications IS: 5831.

In order to be identified, Havell's Cables have their name embossed/printed/indented on outersheath at regular intervals on the outer sheath of Havell's Cables, Voltage Grade, cable size, trade name & year of manufacture are embossed, as desired.

Cables are sequentially marked for length at every metre throughout its length.

Final Testing

Each Havells Cable is tested for all applicable Routine Tests.

From a lot of Cable one cable of each type is tested for Type tests, as per relevant specifications.

Havells conduct its testing at Havell’s India Ltd. cable plant at Alwar for acceptance test as per specification.

Testing of Havells Cables are carried out as per Havells Work Standards for testing, besides applicable standards.