Square D KC34225 Molded Case Circuit Breaker

The KC34225 is a legacy K-frame breaker. The manufacturer's recommended modern drop-in replacement is the PowerPact J-frame JJA36225. It provides the identical 225A capacity, 65kAIC at 480V interrupting rating, and direct plug-on compatibility with standard I-Line panelboards.

Both are 225A, 3-pole K-frame I-Line breakers, but they differ in voltage and fault current limits. The KC34225 features an extra high interrupting capacity of 65kAIC at 480V, but is limited to a 480VAC maximum. The KA36225 has a lower 25kAIC at 480V rating, but can be applied on systems up to 600VAC.

No additional hardware or strap kits are required. This breaker utilizes an I-Line style plug-in design, meaning the line-side jaws press directly onto the busbar stack of a Square D I-Line panelboard or switchboard.

No. The KC34225 is specifically designed for the I-Line busbar system. NQ panels typically require QO or QOB breakers, while NF panels require E-frame breakers. The plug-on jaw configuration of the KC34225 will only fit I-Line distribution equipment.

The KC34225 features a thermal-magnetic trip unit with a fixed thermal element for continuous overloads and an adjustable magnetic element for short circuits. The magnetic dial allows an electrician to tune the instantaneous trip threshold to optimize selective coordination with downstream breakers or account for high-inrush loads.

Yes, it is equipped with standard mechanical lugs on the load end which are AL-CU rated. This means they safely accept either copper or aluminum conductors ranging from 4 AWG up to 350 kcmil. The line side connects directly via the I-Line plug-on jaws.

The KC34225 features a built-in push-to-trip button on the front escutcheon. Pressing this button mechanically trips the breaker, allowing you to exercise the internal linkage and verify that the handle properly moves to the center tripped position.

Yes, this breaker is dual-rated for both AC and DC systems. It can be applied in direct current applications up to 250VDC, offering a maximum interrupting capacity of 10kAIC at 250VDC.