Eaton / Westinghouse KB3225 Molded Case Circuit Breaker

This breaker is designed for installation in legacy Westinghouse panelboards, switchboards, and motor control centers, as well as modern Eaton Series C panelboards.

The original Westinghouse KB3225 is a legacy component. Eaton has transitioned this line to newer Series C models, but exact KB3225 replacements are often used to maintain original system listings without requiring retrofit kits or bus modifications.

Yes, standard thermal-magnetic K-frame circuit breakers like the KB3225 are suitable for reverse feed applications. This allows the breaker to be wired with the line and load connections swapped if needed for your specific panel layout.

The adjustable magnetic trip allows electricians to set the instantaneous short-circuit pickup level. This provides better coordination with downstream devices and helps prevent nuisance tripping during high motor inrush currents.

No, the KB3225 features a thermal-magnetic trip unit with a fixed thermal element and an adjustable magnetic pickup. It does not require a separate rating plug, which is typically only needed for electronic trip units.

The LI designation indicates that the breaker provides Long-Time and Instantaneous protection. The long-time thermal function protects against sustained overloads, while the instantaneous magnetic function clears short circuits immediately.

Always ensure the breaker is completely de-energized and isolated from the power source before making any adjustments to the trip settings to prevent arc flash or electrical shock hazards.