Can you put an Eaton breaker in a Cutler-Hammer panel?

Yes, you can put an Eaton breaker in a Cutler-Hammer panel, and in fact Eaton breakers are designed specifically to replace Cutler-Hammer breakers, provided you match the correct family type. Cutler-Hammer was acquired by Eaton in 1978, and Eaton continues to manufacture the same breaker designs under the Eaton brand. If you have a Cutler-Hammer BR panel, which uses one inch wide black handle breakers, you should use Eaton BR breakers, which are identical and UL listed for that panel. If you have a Cutler-Hammer CH panel, which uses 3/4 inch wide tan handle breakers with a hook, you should use Eaton CH breakers. Eaton BR will fit old Cutler-Hammer BR panels and Eaton CH will fit old Cutler-Hammer CH panels with perfect bus connection and maintain code compliance. You must not mix families, so do not put a BR breaker in a CH panel or vice versa, even if it seems to fit. Also match amperage and poles. Eaton breakers are sold at Home Depot, Lowes, and electrical supply houses and are the official replacement for Cutler-Hammer. Using Eaton breakers of the correct type in your Cutler-Hammer panel is not only allowed but is the manufacturer recommended solution and will preserve the panel's UL listing and safety.