Wood
Zinc
Rubber
Mica
.
Must have low specific resistance
Must have high dielectric strength
Must have low tensile strength
Must have low melting point
More rigidity
Flexibility
High melting point
High mechanical strength
Low resistance
Low melting point
High temperature co-efficient
High dielectric strength
0V - 250V
650V - 33000V
Above 33000V
250V - 650V