Square D MA36600 Molded Case Circuit Breaker

The MA36600 is designed exclusively for installation in Square D I-Line panelboards and I-Line switchboards. Its plug-on line-side connection interfaces directly with the staggered I-Line bus structure.

The primary difference is the mounting style. The MA36600 is an I-Line circuit breaker that stabs directly onto a panelboard bus, whereas the MAL36600 is a unit-mount (lug-to-lug) breaker designed for individual enclosures or backpan mounting.

The direct modern replacement for the legacy MA36600 is the PowerPacT M-Frame MGA36600. The MGA36600 fits into the exact same I-Line bus space but upgrades the protection from thermal-magnetic to a more precise electronic trip unit.

The standard factory lugs on the MA36600 accept three 3/0 AWG to 500 kcmil conductors per phase. These mechanical lugs are rated for both aluminum and copper (Al/Cu) field wiring.

Yes, the magnetic (instantaneous) trip settings can be adjusted. While the thermal element provides a fixed 600-amp long-time overload limit, the magnetic element features an adjustable dial to fine-tune the short-circuit trip threshold.

The LI designation stands for Long-Time and Instantaneous protection. The Long-Time (L) function uses a thermal element to protect against continuous overcurrents, while the Instantaneous (I) function uses a magnetic element to rapidly clear severe short circuits.

The MA36600 is part of the legacy Square D M-frame family. While this specific model is calibrated for a maximum continuous current of 600 amps, the MA I-Line frame itself has a maximum physical capacity of 800 amps.

The breaker uses the Square D I-Line mounting system. The line-side jaws plug directly onto the busbar assembly, while a captive mounting bracket on the breaker is screwed down to physically secure it to the panelboard backpan.

The I-Line stab-in connection eliminates the need to manually land and torque line-side cables near live busbars. This enclosed, plug-on design minimizes exposure to energized components during panelboard population and maintenance.