Square D

Square D is an American manufacturer of electrical equipment headquartered in Andover, MA.

The company was founded on December 15, 1902 by Bryson Dexter Horton and James B. McCarthy. In 1903 they incorporated as the McBride Manufacturing Company. During the first decade of business, the company expanded into various other electrical products. In 1908, the company was renamed Detroit Fuse and Manufacturing. Soon after their renaming to Detroit Fuse and Manufacturing, the company adopted their famous logo: a capital letter D for Detroit enclosed in a square. The logo was stamped on all Square D's switches and products.