Improvements In Non-Tracking Materials

Both accelerated and natural weathering data, previously unpublished, illustrate the excellent outdoor performance of "modified silicone" non-tracking materials supplied by Raychem. Performance outdoors in excess of 30 years is predicted. Also, data from the thermal aging in air of this material indicates a high degree of resistance to thermal oxidation. The use of less expensive non-silicone materials, such as ethylene based polymers is discussed and data is presented suggesting that these materials may be acceptable for use outdoors as high voltage non-tracking insulation, if correctly formulated.