Square D LA36400 Molded Case Circuit Breaker

Yes. It features the standard I-Line plug-in mounting system on the line side, allowing for straightforward installation in Square D I-Line power distribution panelboards and switchboards without requiring a separate mounting strap kit.

The standard factory-installed lug is the AL400LA mechanical lug kit, which is dual-rated for aluminum and copper conductors. If your application specifically requires copper-only terminals, the CU400LA lug kit is the correct alternative.

While the long-time thermal trip is fixed at 400A, the instantaneous magnetic trip is adjustable. It has a magnetic hold current of 2000A and trips at 4000A, providing flexibility when coordinating with inrush currents from large motors or transformers.

"LI" indicates that the breaker's trip unit provides Long-Time (thermal) and Instantaneous (magnetic) protection. It does not feature a Short-Time delay function, which is normally found only on electronic trip units.

The Square D PowerPact L-Frame series serves as the modern direct upgrade. Specifically, the LLA36400U31X is a common replacement that fits standard I-Line panelboards but features a MicroLogic electronic trip unit instead of a traditional thermal-magnetic mechanism.

The LA36400 is the standard interrupting version, providing a 30kA rating at 480VAC. The LH36400 is the high interrupting equivalent built on the same frame, offering a higher 35kA rating at 480VAC and 65kA at 240VAC.

While the thermal-magnetic trip unit itself is suitable for reverse feeding, I-Line plug-in breakers are physically constrained by their jaw connections. They are typically installed as branch breakers feeding from the bus to the lugs, though they can serve as main breakers if properly configured and labeled in an I-Line panelboard.

The LA36400 supports field-installable accessories. For example, if you need a 120VAC to 240VAC shunt trip, you can install the standard LA11021 accessory module on site without needing a custom factory-built breaker.