Dielectric breakdown of insulators frequently results in tree-like patterns. The resulting tree-like patterns have been known to be fractal character. In this paper, chaotic surface tracking patterns observed on polymeric outdoor insulation materials of electrical industry are investigated and simulated. The polymeric samples have been tested according to the IEC 587 Inclined Plane Tracking Test Standard. These samples are subjected to external moisture, vibration and fatigue effect. The carbonized tracking patterns are investigated by calculating their fractal dimensions. The last part of this study was about computer simulation of surface tracking patterns with Brownian motion.