Square D LJA36400U31X - 400 A, 600 V, 3-Pole Plug-In Circuit Breaker | AmpState

Meet the Square D LJA36400U31X, a 400 A, 600 V, 3-pole plug-in molded-case circuit breaker designed to protect branch circuits in panelboards and load centers with unparalleled reliability. Built for fast installation and straightforward maintenance, this breaker is engineered to keep critical electrical systems safe and up and running.

Fast plug-in connection means quicker installations and easier replacements. Swap or upgrade breakers in compatible Square D panelboards in minutes, with minimal panel downtime and fewer wiring adjustments.

• Thermal-magnetic trip unit: combines a thermal element for accurate overload protection with a magnetic element for immediate short-circuit interruption, delivering stable, repeatable protection performance.
• OEM-compatible design: specifically engineered to fit and coordinate with matching Square D load centers and panelboards, ensuring proper fit, bus alignment, and verified protection.
• Three-pole construction: suited for multi-phase circuits and higher current applications, providing cohesive protection across all phases of the load.
• Versatile applications: ideal for residential, commercial, and light industrial distribution where dependable branch-circuit protection is essential.

Technical at a glance

• Part Number: LJA36400U31X
• Amperage Rating: 400 A
• Voltage Rating: 600 V
• Poles: 3
• Mounting Style: Plug-in
• Type: Thermal-magnetic molded case circuit breaker

Practical use cases include main feeders in commercial panel installations, protection for large electrical loads, or serving as a robust branch-circuit breaker for HVAC equipment and other high-current loads. The plug-in design not only simplifies installation and replacement but also reduces the risk of wiring errors during panel servicing.

Choosing the Square D LJA36400U31X means opting for a trusted, purpose-built solution that aligns with your existing panelboard ecosystem. Its 400 A, 600 V, 3-pole configuration delivers strong protection for demanding electrical environments, while the plug-in architecture keeps downtime to a minimum and serviceability straightforward.