Orient-polymer insulator shed, silicone rubber

The housing and weathersheds shall be made of silicone rubber material in order to maintain their hydrophobicity during long term service in critical environments.

A minimum thick sheath of 3.0 mm of Silicone Rubber shall be extruded or injection moulded on the reinforced fiberglass rod. The polymer sleeve and weathershed insulating material shall have a chemical structure of 100 percent silicone rubber before fillers are added.

The silicone rubber shall be firmly bonded to the rod, be seamless, smooth and free from imperfections. The strength of the silicone rubber to rod interface shall be greater than the tearing strength of the silicone rubber.

The weathersheds shall be firmly bonded to the sheath, vulcanized to the sheath or moulded as part of the sheath and be seamless smooth and free from imperfections. The strength of the silicone rubber weathershed to sheath interface shall be greater than the tearing strength of the silicone rubber.

Weathersheds shall be at intervals to provide optimum electrical performance and the weathershed designs should provide a protected bottom surface that tends to keep dry in wet conditions.

The insulator shall be capable of withstanding high pressure power washing. A power wash test shall be performed on polymer insulators to

demonstrate that the units can be power washed. This test shall be a water spray at a shed seam approximately 3 meter from the insulators. The spray shall be a solid stream through a 6mm diameter nozzle at 550 psi for a period of ten minutes. There shall be no signs of water entering through or under the outside weathershed into the core or at the polymer hardware interface into the core.

The gap between hardware base and housing shall be sealed by an elastomer with permanent elasticity. The sealing shall stick permanently to the surface of the material as well as to the housing.

The base should be attached to insure a uniform distribution of the mechanical load to the rod.