Square D LJA36400U33X - 400 A, 600 V, 3-Pole Plug-In Circuit Breaker | AmpState

Square D LJA36400U33X is a high‑capacity 400 A, 600 V, 3‑pole plug‑in molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short‑circuit protection in panelboards and load centers. The plug‑in design enables fast installation and easy replacement, helping minimize downtime during upgrades or maintenance.

Inside, a thermal‑magnetic trip unit provides stable, repeatable protection. The thermal element handles normal overloads with precision, while the magnetic element responds aggressively to high‑energy short circuits, interrupting current quickly to protect equipment and wiring.

Designed to integrate with matching OEM load centers and panelboards, this 3‑pole breaker ensures proper fit, reliable bus connection, and coordinated protection across three‑phase distributions. It’s well suited for residential, commercial, and light industrial applications where robust protection and quick serviceability are priorities.

• Fast plug‑in connection for quick installation and painless replacement, reducing field wiring time and downtime.
• Thermal‑magnetic trip unit delivers stable protection across varying loads and ambient conditions.
• OEM‑compatible fit with matching Square D load centers and panelboards for seamless integration.
• 3‑pole design ideal for three‑phase distribution and high‑demand branch circuits.
• 600 V rating suitable for higher‑voltage commercial and light industrial applications.

• Manufacturer: Square D
• Part Number: LJA36400U33X
• Type: Thermal‑magnetic molded case circuit breaker
• Amperage Rating: 400 A
• Voltage Rating: 600 V
• Number of Poles: 3
• Mounting Style: Plug‑in
• Application: Branch circuit overcurrent and short‑circuit protection

Use this breaker to upgrade or equip panelboards and load centers that demand heavy‑duty branch protection. Whether you’re restoring a critical commercial system or extending a light industrial distribution network, the LJA36400U33X delivers reliable protection with install efficiency and OEM alignment that reduces rework and ensures long‑lasting performance.