Compound insulator is composed of insulator mandrel, silicon rubber umbrella cover and metal part connection in the both mandrel is short for epoxy resin glass fiber lead main function of insulator mandrel is to support mechanical has a very high tensile strength up to specific strength(tensile strength/weight) is about 5-6 times as good structural carbon steel.and it won't descend too many with long term also is a main part of internal mandrel has a very high insulation property even it affects by damp.So it can satisfy machine and electricity strength requests of compound Insulator well.Silicon rubber umbrella cover is mainly used to protect insulator mandrel from rain or snow.
It provides necessary cree page distance and product external base is high polymer silicon rubber added fire retardant, coupling agent and has a good dielectric property and corrosion also has a good counter bending, creep resisting and impact resistance.http://www.niuelec.com/Insulators-24-1.html