A pin insulator is a device that isolates a wire from a physical support such as a pin (a wooden or metal dowel of about 3 cm diameter with screw threads) on a telegraph or utility pole. It is a formed, single layer shape that is made out of a non-conducting material, usually porcelain or glass.
Pin insulators are used to hold conductors in place, while post insulators are used on power poles. Pin insulators generally have a smaller profile and are designed to reduce stress on the conductor, while post insulators are larger and designed to provide more support for the conductor. Pin insulators usually have two or three pins, while post insulators typically have four or more pins. it consists of a single or multiple units. it is secured to the cross-arm on the pole. it used only to 33 KV.
Beyond operating voltage of 33 KV, it becomes to bulky and uneconomical. there is a groove on the upper end of the insulator for housing the conductor. the conductor passes through this groove and is bound by annealed wire of the same material as the conductor. Pin-type insulators are used for the transmission and distribution of electric power at voltages up to 33 kV.
Beyond the operating voltage of 33 kV, the pin-type insulators become too bulky and hence uneconomical.
The pin insulator uses non-conducting material like porcelain, ceramic, silicon rubber, polymer, etc.