2018.018.088 [Insulator, Communication]

Spool or knob insulators typically have a non-threaded hole in the center for mounting and a wire groove around the outside. These insulators are used for dead ending a communication or power line and are often found mounted on racks on the sides of buildings where the wires enter the building. They are also used for wire transposition where two or four spools are mounted such that the wires can tie off and cross. There is currently no hobby numbering scheme for porcelain spools. For any use other than instructional resources, please check with the organization that owns this item regarding copyright restrictions.