Square D MA36400 - 400 A, 3-Pole Plug-In Circuit Breaker | AmpState

Powerful, dependable protection for high-current branch circuits, the Square D MA36400 is a 400A, 3-pole plug-in molded case circuit breaker designed for panelboards and load centers. Built to deliver consistent performance under demanding loads, it's a smart choice for commercial, industrial, and multi-residential settings where reliability matters.

Fast, easy installation with a plug-in connection minimizes downtime during upgrades or replacements. The plug-in mounting style ensures secure seating in compatible panelboards, reducing the risk of loose connections that can compromise protection.

Thermal-magnetic protection you can trust integrates a trip unit that provides stable overload protection with precise, repeatable trips for short-circuit events. This means fewer nuisance trips during normal operation and strong response when faults occur.

Built for compatibility and broad use designed to mate with matching OEM load centers and panelboards, the MA36400 is suitable for residential, commercial, and light industrial applications. Its 3-pole design is ideal for 3-phase systems common in larger installations, supporting reliable distribution across multiple circuits.

Product highlights

• Amperage rating: 400A
• Poles: 3-pole
• Mounting style: Plug-in
• Type: Thermal-magnetic molded case circuit breaker
• Part number: MA36400
• Manufacturer: Square D

Use cases and practical applications

Ideal for replacing aging breakers in panelboards to safeguard large residential loads, commercial lighting circuits, HVAC feeders, and industrial distribution. The 3-pole design makes it suitable for 3-phase systems found in offices, retail spaces, and light manufacturing. With a 400A rating, you can support substantial loads without frequent trips, while the fast plug-in installation keeps downtime to a minimum during service or upgrades.

If your electrical setup requires dependable, OEM-compatible protection in a compact plug-in package, the MA36400 delivers reliable thermal-magnetic performance and straightforward integration into compatible Square D panelboards and load centers.