Item 74833 - Glass electrical insulator, ca. 1880 Item 74833 - Glass electrical insulator, ca. 1880 Contributed by Maine Historical Society Item 74833 Zoom 3197px x 4200px - 10.7"w x 14.0"h @ 300dpi | Need a larger size? *Credit line must read: Collections of Maine Historical Society Image Info This glass insulator was used for low-voltage overhead electrical distribution wires. Insulators keep electric current from "leaking" out of lines. Show Details