Evaluating the electrical tracking and erosion resistance of polymeric housing materials is an essential task performed in the development of outdoor insulators. “Tracking” means the formation of a surface carbonaceous path, and “erosion” means weight loss of the housing material. An absolute measurement of the tracking and erosion resistance is not possible; only relative ranking of composites can be achieved using the standard tracking and erosion tests. During the early use of organic insulating materials, failure due to tracking was a major concern, and therefore standard screening methods were proposed to evaluate the tracking rather than the erosion resistance. Erosion has become more important following the development of tracking resistant composites containing high levels of inorganic fillers.