Insulator is one of the equipment that is very important in the distribution of electric power systems. Insulation is needed to separate two or more live electric conductors so that between these conductors there is no electric jump or spark. Because of the importance of the insulator in the electric power system, it must be maintained its fairness. Disturbance to the insulator is caused by several factors and is generally caused by external factors, namely environmental factors. The outdoor insulator is affected by these environmental factors and the effects of pollution from the environment. These environmental factors greatly affect the performance of the insulator. To improve the performance of insulators, several attempts have been made, such as the use of new materials, surface coatings to designs to increase dielectric strength. Systematic efforts to improve insulator performance require an understanding of insulator behavior. Insulator characteristics are divided into two, namely mechanical characteristics and electrical characteristics.