To assemble the conductor inside the enclosure supporting insulators are required. They are used for holding the conductor at a required distance from ground and to support loads due to the conductor weight and stresses due to conductor expansion and short circuit faults.

Insulators are provided with shock absorber devices that allow the free expansion. The insulator is fixed into a box welded to the enclosure that permits easy maintenance. A.S. uses insulators made of porcelain or epoxy resin. The number and the arrangement depend on the operating ratings.