The Glass Insulator

Blue Colored Hemingray CD257 “Mickey Mouse Ears” Glass Insulator

The Hemingray Glass Company operated between 1848-1972 and was the largest manufacturer of glass insulators in the world. This five inch high cable-style insulator by Hemingray was produced from 1910 to 1940. It was used in secondary power distribution and had a voltage rating of  6,600 volts. They were produced in two versions: a regular saddle groove (as shown) and a wide saddle groove for heavier gauge wire. It was patented on June 17, 1890.