The insulation screen shall consist of a non-metallic semi-conducting layer in combination with a metallic layer.
- Non-metallic part: The non-metallic layer shall be extruded directly upon the insulation of each core and shall consist of either a strippable or bonded semi-conducting compound.
- Metallic part: Metallic layer shall consist of one or more tapes or a concentric layer of wires or a combination of wires and tape.
Inner Covering / Separation Sheath
Inner covering may be extruded or lapped. When the underlying metallic layer and the armour are of different materials, they shall be separated by an extruded sheath of PVC or Polyethylene or LSF as applicable.
Armour shall be as per IEC 60502-2 of the following types:
Armour material shall be Galvanized steel for three core cables and Aluminium for single core cables. Armour of other material as per IEC 60502-2 can be provided upon request.
- Round Wire Armour
- Double Tape Armour
Outer sheath shall be extruded PVC type ST2 as per IEC 60502-2, Type 9 as per BS 7655. Special type of sheathing material such as fire retardant PVC or anti-termite and anti-rodent PVC, ultraviolet PVC, Oil resistant PVC, etc. are available on request also other special sheathing materials such as LLDPE, MDPE, HDPE, LSF, CPE etc are available.
For 3 core cables, Red, Yellow and Blue colored strips shall be applied under the metallic screen throughout the length of the cable for phase identification.
For single core cables no phase identification shall be provided.