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What is the difference between specified and classified circuit breakers?
Friday, October 29, 2021
“Specified" breakers are the ones approved by the manufacturer of an electrical panel as acceptable for installation in their panel. A specified breaker is usually also manufactured by the same company as the panel, but not always. Thomas & Betts, for example, approved some 120-volt Challenger breakers for their panels in the 1990s.
“Classified” circuit breakers are made by one manufacturer to be installed as replacement breakers in a panel produced by another manufacturer. They are officially called “UL Classified,” meaning that Underwriters Laboratories has tested and approved them for installation in particular manufacturers' panel boards—often for companies that are no longer in business and replacement breakers would be otherwise not available, but also for currently available breakers.
Eaton, for example, manufactures UL Classified breakers that are approved for multiple different brands of panels. Download EatonClassifiedBreakers for the full list. Original equipment manufacturers obviously don’t like competitors encroaching on their market and may threaten that their warranty is voided if classified breakers are used in their panel.
Just because one manufacturer's breaker snaps into place in a different manufacturer’s panel does not mean it is safe or acceptable. Sometimes we see five or six different brands of breakers in a single, older panel. You can be sure that most, if not all of them, are not approved to be there. Also see our articles Can you add circuit breakers by different manufacturers to an electric panel if they fit? and How do I find out the manufacturer of an electrical panel? for more on this issue.
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