Insulating material is generally used as a protective coating on electrical conductor and cables. Cable cores which touch each other should be separated and insulated by means of insulation coating on each core, e.g. Polyolefin, PVC Heat Shrink Sleeve, Silicon, Teflon, Fiber Glass etc.
Hanging disk insulators (bushings) are used in high voltage transmission bare cables where they are supported by electrical poles. Bushings are made from glass, porcelain, or composite polymer materials.