Question

Why rubber is an insulator

Answer 1

The properties of rubber will also cause the electrons to slow down and eventually prevent them from moving at all.
Keeping electricity bound within the material is the main goal of an insulator – making rubber a very good choice, especially in the form of electrical mats.

Main role of an insulator is to keep electricity within the material and rubber is the best material because of that it’s used in the electric wire. Rubber is the best insulator that could be molded to shape and extruded.