When did Cutler-Hammer go out of business?

Cutler-Hammer did not go out of business in the sense of failing or closing down; it was acquired and its brand was gradually phased into Eaton. Cutler-Hammer was founded in 1893 in Milwaukee as a manufacturer of electrical controls and became a leading brand of circuit breakers and motor starters. Eaton Corporation acquired Cutler-Hammer in 1978, so as an independent company it ceased to exist then, but the Cutler-Hammer brand and product lines continued to be manufactured and sold under Eaton ownership for decades. Eaton continued to use the Cutler-Hammer name on breakers, panels, and industrial controls well into the 2000s because electricians recognized and trusted the name. Starting in the late 2000s and early 2010s, Eaton began rebranding products from Cutler-Hammer to Eaton, so new breakers are now labeled Eaton BR and Eaton CH instead of Cutler-Hammer BR and CH. The Cutler-Hammer brand still appears in catalogs and on legacy equipment, but new production is branded Eaton. So Cutler-Hammer did not go bankrupt; it was successfully integrated into Eaton, which remains one of the largest electrical manufacturers in North America, and its designs live on as Eaton breakers.