In 6.6 kV system AC (unearthed) grade having stranded aluminium conductors cables are used. Their insulation’s are as follows.
1. XLPE – Crossed linked polyethylene insulation.
2. FRLS PVC – Fire retardant low smoke insulation with PVC inner and outer insulation. In RB copper conductor stranded cables are used.
3. FS – fire survival insulation.
4. HR PVC – heat resistant insulation.
In 415 V system 1100 V grade copper or aluminium stranded cables are used. Their insulations are HR PVC and FS type.
