Square D LLA36400U33X - 400 A, 600 V, 3-Pole Plug-In Circuit Breaker | AmpState

Meet the Square D LLA36400U33X, a robust 400 A, 600 V, 3-pole plug-in molded case circuit breaker designed to shield branch circuits in panelboards and load centers. Built for dependable overcurrent and short-circuit protection, this unit combines fast installation with precise protection that electricians trust in residential, commercial, and light industrial settings.

• High-current, high-voltage protection: 400 A amperage rating and 600 V capacity safeguard powerful electrical loads without compromising safety.
• Three-pole, plug-in design: Simplified, quick-to-install plug-in connection to compatible OEM panelboards and load centers, minimizing downtime during upgrades or replacements.
• Thermal-magnetic trip unit: Delivers stable, repeatable protection by combining thermal overcurrent sensing with magnetic instantaneous tripping for fast response to short circuits.
• OEM-compatible: Engineered to fit matching Square D load centers and panelboards, ensuring reliable mechanical and electrical compatibility.
• Versatile applications: Ideal for residential service panels, commercial panels, and light industrial distribution where dependable branch circuit protection is essential.

Why this matters

In any electrical system, the right circuit breaker not only stops faults quickly but also maintains safe operation under varying conditions. The LLA36400U33X’s thermal-magnetic trip curve provides predictable behavior across ambient temperatures, long-term stability, and consistent trip characteristics. Its plug-in format reduces installation complexity and downtime—keeping projects on schedule and service calls efficient.

Use cases and scenarios

• Upgrading a residential main panel to accommodate higher-capacity circuits without rewiring the enclosure
• Replacing aging breakers in commercial load centers to restore reliable feeder protection
• Installing in light industrial panels to manage multiple large loads with coordinated protection
• Specifying a plug-in breaker for new installations where fast deployment and future upgrades are anticipated

Specs at a glance

• Manufacturer: Square D
• Part number: LLA36400U33X
• 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

Whether you’re upgrading an existing panel or equipping a new installation, AmpState’s Square D LLA36400U33X delivers reliable protection with a straightforward plug-in approach. Choose this 3-pole, 400 A breaker for solid, long-lasting performance in the environments that demand it most.