Composite insulator is also called synthetic insulator. Its main structure generally consists of three parts: shed sheath, fiberglass core rod and end fittings.

The shed sheath is generally made of organic synthetic materials, such as ethylene-propylene rubber, high-temperature vulcanized silicone rubber, etc.;

FRP core rod is generally a FRP composite material with glass fiber as reinforcement material and epoxy resin as matrix;

End fittings are generally carbon cast steel or carbon structural steel with a hot-dip galvanized layer on the outer surface.

Therefore, there is no metal rod in the middle. The fiberglass core rod and silicone rubber are both insulating parts to achieve insulation.