Effect on the electrical properties of fillers in silicone rubber for outdoor insulation

The effect on the electrical properties of adding CaCO/sub 3/ filler to silicone rubbers for outdoor insulation was investigated. Silicone rubber specimens were prepared by adding CaCO/sub 3/ and ATH as fillers in specified ratio to silicone base gum. The blend ratio of ATH and CaCO/sub 3/ in silicone rubber specimens was changed from 100:0 to 63:37. Dry arc, tracking and erosion resistance performances, and the water absorption-dielectric properties relation were mainly studied. The results of increasing the amount of CaCO/sub 3/ were an increase in the rate of water absorption, reduction of dry arc, tracking, erosion resistance performances and dielectric strength after water immersion.