Square D PKA36040U31 A - 400 A, 600 V, 3-Pole Plug-In Circuit Breaker | AmpState

Meet the Square D PKA36040U31A 400A, 600V, 3-pole plug-in molded case circuit breaker from AmpState. Built for dependable branch circuit overcurrent and short-circuit protection, this unit is ready to elevate reliability in panelboards and load centers across commercial, industrial, and even residential-scale installations.

Key advantages that keep systems running

• Fast plug-in connection for quick installation and effortless replacement, minimizing downtime during panel maintenance or upgrades.
• Thermal-magnetic trip unit delivers stable, repeatable protection by combining thermal sensing for overload with magnetic trip for short circuits, reducing nuisance trips and safeguarding connected equipment.
• Three-pole design supports three-phase distribution, ideal for modern commercial and light-industrial electrical systems that require robust, coordinated protection.
• High-current capacity 400A rating paired with a 600V rating provides reliable protection for large feeders and main/branch circuits in versatile panel configurations.
• OEM-compatible designed to pair with matching Square D load centers and panelboards, ensuring a precise fit and reliable performance within your established electrical architecture.
• Broad application range suitable for residential, commercial, and light industrial environments where dependable overcurrent and short-circuit protection is critical.

With its plug-in molded-case construction, this breaker integrates seamlessly into compatible panelboards, delivering quick upgrades or replacements without invasive rewiring. The 3-pole configuration is ideal for three-phase feeds, while the thermal-magnetic trip unit provides predictable response across varying loads and fault conditions—helping protect motors, lighting, HVAC, data-center infrastructure, and other critical circuits.

Technical specifications at a glance

• Manufacturer: Square D
• Part Number: PKA36040U31A
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400A
• Voltage Rating:
600V
• Number of Poles: 3
• Mounting Style: Plug-in
• Application: Branch circuit overcurrent and short-circuit protection

Who it’s for and how you’ll use it

Ideal for facilities managers, electrical contractors, and engineers assembling or upgrading panelboards in warehouses, offices, manufacturing spaces, and other commercial or light-industrial settings. When you need a reliable, OEM-compatible plug-in breaker that can handle substantial three-phase loads, the Square D PKA36040U31A offers a straightforward path to enhanced safety and system continuity.

Practical tips for installation and use:

• Verify that your panelboard is compatible with the PKA series plug-in breakers to ensure a proper fit and coordinated trip characteristics.
• Follow standard safety practices for live-panel work; ensure power is disconnected before installation and check torque specifications on all terminations.
• Use the 400A rating to protect feeder circuits and main distribution paths; pair with appropriately rated conductors and protective devices upstream and downstream.
• When replacing an existing unit, confirm the trip unit settings are appropriate for the circuit being protected to avoid nuisance trips or insufficient protection.