Cap and pin type Post Insulators are designed mainly to support disconnecting switches, bus bars, conductors, and equipment for substations. The Post Insulators are capable of being stressed in tension, compression, flexion, torsion and combined stresses upto the specified limits. These Post Insulators are more economical than other types of insulators used for similar applications. Cap and pin type Post Insulators are divided into two main groups, no stacking and stacking units. Single units are available for service voltage upto 36kV and multi-unit stacks are available for service voltage upto 245kV. These Post Insulators are extremely reliable.