Pin insulator
From Wikipedia, the free encyclopedia
A Pin Insulator is a ceramic or glass device that isolates a wire from a physical support (or "pin") on a telegragh or utility pole. By contrast to a strain insulator, the pin insulator is directly connected to the supporting pole. The earliest pin insulators predate the string insulator and were deployed before about 1830. Pin insulators are still manufactured and deployed as of 2007.
The pin insulator is designed to support the weight of the wire while providing electrical insulation of the wire from the supporting pin. Pin insulators are almost always deployed in the open air, so isolation when wet is a major consideration.
The "pin" is typically a wooden dowel of about 3cm diameter with screw threads. The pin insulator has threads so that it can be screwed onto the pin. A typical pin insulator is more than 10cm in diameter and weighs one Kg or more. Size depends on the voltage to be isolated the the weight of span of wire to be supported.
