Transmission & Distribution: Insulators


Ball-strain insulator, ca. 1920

Ball-strain insulator, ca. 1920
Item 74836   info
Maine Historical Society

Nicknamed the "Johnny Ball," this insulator is made of a composite material containing asphalt, shellac and asbestos.

Strain insulators are used in the guy wires supporting utility poles or radio antennas to break the electrical path and prevent short circuits or grounding.

Item 12 of 15