Square D LXI36400 Molded Case Circuit Breaker

This breaker is designed exclusively for use in Square D I-Line panelboards and switchboards. It features an I-Line style plug-on connection for the line side, which mounts directly onto the panel's busbar stack.

The LSI designation means the electronic trip unit provides adjustable Long-Time (overload), Short-Time (short circuit with intentional delay), and Instantaneous (immediate short circuit) protection. This adjustability allows for precise selective coordination with downstream breakers in your electrical system.

The standard load side lugs accept either one 500-750 kcmil aluminum or copper wire, or two 3/0 AWG to 250 kcmil aluminum or copper wires per phase.

Yes, the LXI series is a legacy frame that has been superseded by the PowerPact L-Frame. A common modern equivalent is the LRA36400U43X for an exact 200kAIC match at 480V, or the LLA36400U43X if a 100kAIC rating is sufficient. Both feature I-Line mounting and LSI electronic trip units.

The breaker features plug-on jaws on the line side that press directly onto the I-Line busbar stack. A mounting bracket and retaining screw secure the breaker to the panelboard backpan, while the load side uses standard mechanical lugs for wire termination.

No, this breaker features an LSI trip unit (Long-Time, Short-Time, Instantaneous), which does not include integrated ground fault protection. If ground fault protection is required for your application, an LSIG trip unit or external ground fault relay would be necessary.

The primary difference is the mounting style. The LXI36400 features an I-Line plug-on connection for use in Square D panelboards, while the LXL36400 is a feed-thru (unit-mount) breaker that uses mechanical lugs on both the line and load sides.