Square D KC34250 Molded Case Circuit Breaker

The KC34250 is an I-Line style plug-in breaker designed for use with Square D I-Line panelboards and switchboards. It is not compatible with standard load centers like the NQ, NF, or QO series.

No, the KC34250 features an integrated I-Line style plug-in connection. It mounts directly onto the busbar of Square D I-Line panelboards and switchboards without requiring an external mounting bracket or hardware kit.

The standard lugs on this breaker accept aluminum or copper wire ranging from 4 AWG up to 350 kcmil. Always ensure proper torque specifications are met during installation to prevent terminal overheating.

The breaker provides an extra-high interrupting rating of 100 kAIC when installed on a 240VAC system. When applied to a 480VAC system, the short-circuit interrupting capacity drops to 65 kAIC. You must verify the available fault current at your specific installation voltage.

Yes, it features an LI (Long-Time and Instantaneous) thermal-magnetic trip unit. The thermal long-time protection is fixed, while the magnetic instantaneous trip function is adjustable to accommodate different inrush currents without nuisance tripping.

The LI designation indicates that the breaker provides Long-Time and Instantaneous protection. The long-time function acts as thermal protection against continuous overloads, while the instantaneous function provides magnetic protection that trips the breaker immediately during a severe short circuit.

Yes, the KC34250 shares the exact same 4.5-inch mounting height and physical K-frame footprint as the KA and KH series breakers. It can physically replace them in an I-Line panelboard, providing a higher extra-high interrupting capacity than standard KA or high-interrupting KH models.

Square D legacy K-frame breakers have been superseded by the PowerPact J-frame series. When replacing a KC34250, look for a 250A PowerPact J-frame with an I-Line connection while verifying that the short-circuit ratings match your system requirements.