Square D LGA36400U43X - 400 A, 3-Pole Plug-In Circuit Breaker | AmpState

Meet the Square D LGA36400U43X — a 400 A, 3-pole plug-in molded case circuit breaker built for dependable branch circuit overcurrent and short‑circuit protection in panelboards and load centers. Its fast plug-in connection makes installation and replacements quick and simple, reducing downtime and keeping critical power flowing where you need it most. The thermal-magnetic trip unit delivers stable, repeatable protection, so you get predictable responses to overloads and faults without unnecessary trips.

• Fast plug-in installation — slide-in mounting for rapid service upgrades and effortless replacements, minimizing panel downtime.
• Thermal-magnetic protection — precise trip characteristics that respond to both overloads and short circuits, helping protect wiring and connected equipment.
• OEM-compatible — designed to pair with matching Square D OEM load centers and panelboards, preserving system integrity and UL compliance.
• High-current capability — 400 A rating suits larger residential feeders, commercial panels, and light industrial applications requiring robust protection.
• Three-pole design — provides coordinated protection for three-phase circuits, enhancing safety and reliability in multi‑phase systems.

This breaker is ideal for upgrading or expanding panel infrastructure where a reliable 400 A, 3‑pole plug-in solution is needed. Use it as a main feeder protection in larger residential subpanels, as a primary safeguard in commercial panelboards, or for retrofit projects where quick plug-in compatibility and durable performance matter most.

Specifications at a glance

• Manufacturer: Square D
• Part Number: LGA36400U43X
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400 A
• Number of Poles: 3
• Mounting Style: Plug-in
• Application: Branch circuit overcurrent and short-circuit protection

Choose the Square D LGA36400U43X when you need a robust, plug-in solution that pairs with your existing panelboard ecosystem, delivers predictable protection, and keeps high‑current circuits safely guarded. A smart, practical upgrade for professionals who demand reliability, fast serviceability, and compatibility in one trusted package.