XLPE is an abbreviation for cross-linked polyethylene or vulcanized polyethylene. The basic material is low-density polyethylene. Polyethylene is thermoplastic material consisting long chain of hydrocarbon molecules. Cross- linking of polyethylene takes place in three- dimensional network. As such XLPE has strong resistance to deformation at higher temperature. XLPE is non polar material which processes high insulation resistance and dielectric strength and low dielectric losses.The advantages of XLPE Insulated cables in comparison to PVC insulated cables are as under:
- Higher Current rating, higher Short Circuit Rating Approx 1.2 times that of PVC.
- Thermosetting in nature.
- Higher insulation resistance – 1000 times more than PVC cables.
- Higher resistance to moisture.
- Better Resistance to surge currents.
- Low Dielectric Losses.
- Better resistance to chemicals.
- Longer service life.
- Comparatively higher cable operation temperature 90°C and short circuit temperature 250°C.
- Lower Laying Cost because of comparatively smaller diameter of cable and lighter weight*.
- Lower installation charges as the diameter of cable is comparatively lesser with smaller bending radius, requiring less space requirement for laying of cables.
- ** One size lower cable can be used as compared to PVC insulated cable.
* Density of XLPE is lower than PVC
** For longer cable length voltage drop shall be considered
V-Marc XLPE cables manufactured confirming to IS: 7098 (Part-1) or as per Customer’s requirements.
The Conductor of power cable is generally made from EC grade aluminum and annealed high conductivity copper is used for control cables. All conductors conform to IS: 8130:1984. Power Cables with copper conductor can also be supplied as per customer’s requirement.
The Conductor is solid/ stranded/ bunched as per the requirements.
The conductor is insulated with the XLPE (cross –linked Polyethylene) compound by extrusion.
Inner Sheath (Common Covering)
The laid up cores shall be provided with an inner sheath applied either by extrusion or by wrapping. The fillers and inner sheath shall be on the following:
- Unvulcanised rubber
- Thermoplastic materials
Single Core cables do not have inner sheath
It shall ensure that it is as circular as possible.
Armouring shall be applied over the insulation in case of single core cables and over the inner sheath in case of twin, three and Multicore cables. The armour wires/ strips shall be applied as closely as practicable.
Where the calculated below armouring does not exceed 13mm.The Armour shall consist of galvanized round steel wire and where the calculated diameter below the Armouring greater than 13mm, the armour shall consist of either galvanized round steel wire or galvanized steel strips. Generally consist of steel strips.
The outer sheath shall be applied by extrusion. It shall be applied over the insulation in case of unarmoured single core cables, over the inner sheath in case of unarmoured twin, three, Multicore cables and over the armouring in case of armoured cables. The colour of outer sheath shall be black or any other colour as per Customer’s requirements.
The name V-Marc is embossed on the outer sheath of the cable and at regular intervals. The word ELECTRIC is also embossed to distinguish these cables from telephone cables and word MINING is also added in case of mining cables. The FR-LSH cables bear an additional legend FR-LSH as the case may be. Any other necessary information required by the customer’s is also embossed.