A pin insulator is a device that isolates a wire from a physical support such as a pin 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. It is thought to be the earliest developed overhead insulator and is still popularly used in power networks up to 33 KV. Single or multiple pin insulators can be used on one physical support, however, the number of insulators used depends upon the application's voltage.
An insulator of a telephone transmission line
A pin insulator ceramic plate used for 20 KV lines
A sparkling CD 145 or "beehive" insulator from the telegraph era made by the Brookfield Glass Company circa 1882.
The same snowy CREB 145 sitting on its side
An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors. The most common examples are non-metals.
Ceramic insulator used on an electrified railway
Three-core copper wire power cable, each core with an individual colour-coded insulating sheath, all contained within an outer protective sheath
PVC-sheathed mineral-insulated copper-clad cable with two conducting cores
Pin-type glass insulator for long-distance open-wire transmission for telephone communication, manufactured for AT&T in the period from c. 1890 to WW-I; It is secured to its support structure with a screw-like metal or wood pin matching the threading in the hollow internal space. The transmission wire is tied into the groove around the insulator just below the dome.
