When selecting insulators,it’s necessary to describe the insulator parameters by the following terms:

1.Creepage Distance 

shortest distances the sum of the shortest distances along the surface on an insulator between two conductive parts which normally have the operating voltage between them

2.Arcing Distance

Shortest distance in air external to the insulator between the metallic parts which normally have the operating voltage between them

3.Specified Mechanical load(SML)

Load, specified by the manufacturer,which is used for mechanical tests End fitting

4.Integral component or formed part of an insulator intended to connect it to a supporting structure,or to a conductor,or to an item of equipment,or to anoyher insulator

5.Specified cantilever load(SCL)

Cantilever load which can be withstood by the insulator when tested under the prescribed conditions.

6.Maximum cantilver Load(MDCL)

Cantilever load level above which damage to the insulator begins to occur and that should not be exceeded in service

7.Specified tensile load(STL)

Tensile load which can be withstood by the insulator when tested undrf the prescribed conditions.This value specified by the manufacturer.