Square D LAP36400MB Molded Case Circuit Breaker

The MB suffix designates that this breaker features a short operating handle. This modification is typically used when the unit is installed as a main breaker to ensure switchboard or panelboard doors close properly without handle interference.

Yes, the unit-mount LAP series serves as a drop-in replacement for older legacy L-Frame breakers, such as the LAL36400 or LHL36400. You must ensure the short handle design meets your specific enclosure and deadfront clearance requirements.

This breaker utilizes a unit-mount, or bolt-on, configuration rather than a Square D I-Line plug-on design. It secures directly to the panel backpan using mounting screws and connects to the electrical bus or cables via its integrated terminal lugs.

The LI code indicates that the thermal-magnetic trip unit includes Long-Time (L) and Instantaneous (I) protection functions. The long-time function provides fixed thermal overload protection, while the instantaneous function offers an adjustable magnetic short-circuit response.

Yes, the factory-installed lugs accept either a single conductor ranging from 1 AWG to 600 kcmil, or two parallel conductors ranging from 1 AWG to 250 kcmil. These lugs are rated for both aluminum and copper wire.

Yes, this legacy L-Frame breaker can be upgraded to the modern Square D PowerPacT L-Frame series. Retrofit kits are available to adapt the newer PowerPacT breakers into existing LA, LAL, or LAP panel footprints.

This breaker is equipped with a Visi-Trip indicator that visually flags when a trip event has occurred. It also features a push-to-trip button on the faceplate, allowing personnel to mechanically exercise the tripping mechanism safely without exposing live electrical parts.