The market for composite insulators is growing steadily, both in long-rod line applications and hollow core station insulators. Composite designs typically use engineered polymers which offer higher mechanical strength, greater design flexibility, reduced weight, and lower breakage rates than ceramic components. The emerging shift to composites adds new importance to the debate over which polymeric material should be used for the housing. Insulator field experience and extensive, multi-stress lab testing of different elastomer formulations have shown silicone’s unique surface behavior to be an advantage in these applications.