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 thought to be the earliest developed overhead insulator and is still popularly used in power networks up to 33 KV.
The 120 in 120 kn disc insulator refers to mechanical strength of disc insulator. The kn in 120 kn disc insulator refers to mechanical strength unit. ... 120 kn disc insulator means the electrical products called this name according to the insulator properties.