Square D Q4L2300 Molded Case Circuit Breaker

The Q4L2300 can be installed in Square D LA400F, LA400S, LA400R, LA400AWK, and LA400DS circuit breaker enclosures. It is also suitable for use in standard Square D switchboards and motor control centers.

The standard AL400LA lugs accept either one 1 AWG to 600 kcmil conductor or two 1 AWG to 250 kcmil conductors (aluminum or copper). Both wire configurations require a tightening torque of 372 lb-in (42 N.m).

The Q4L frame is a legacy molded case circuit breaker. For modernizations or new installations, Schneider Electric has transitioned to the PowerPacT L-frame series as the current replacement path.

Yes, Q4L, LAL, and LHL breakers share the same physical dimensions and mounting footprint. However, you must verify that the 25kAIC interrupting rating of the Q4L2300 meets or exceeds the available fault current of your specific application before substituting.

No, the Q4L2300 features a thermal-magnetic trip unit with fixed long-time and fixed instantaneous trip functions. It does not offer adjustable dials for customizing the trip curve.

As a unit-mount, feed-thru breaker, the Q4L2300 bolts directly to a mounting pan or backplate and requires wired lug connections on both the line and load sides. It cannot plug directly onto an I-Line busbar system.

The LI designation means the breaker provides Long-Time (L) protection against overloads and Instantaneous (I) protection against short circuits. Both functions operate using standard thermal-magnetic technology.

Routine maintenance should include verifying that lug torque remains at the specified 372 lb-in, checking the terminals for signs of thermal discoloration, and exercising the breaker mechanism. Always ensure the equipment is fully de-energized before performing inspections.