Square D LLL36400U31X - 400 A, 3-Pole Circuit Breaker | AmpState

Meet the Square D LLL36400U31X, a robust 400 A, 3-Pole molded case circuit breaker designed to safeguard panelboards and loadcenters with precision. Trusted by professionals and available through AmpState, this unit delivers dependable branch circuit overcurrent and short-circuit protection for demanding electrical systems.

Engineered for real-world reliability, this breaker combines a compact molded-case design with a thermal-magnetic trip mechanism. The result is stable, repeatable protection that responds appropriately to overloads while delivering rapid magnetic trips for high-current faults—minimizing downtime and protecting wires, devices, and panels.

• Space-efficient design: Compact form factors maximize usable panel space, helping you fit more protection where it matters.
• Thermal-magnetic protection: Thermal protection handles gradual overloads with predictable timing, while magnetic protection instantly trips on severe faults.
• 3-pole configuration: Ideal for three-phase systems common in commercial and light industrial applications, enabling coordinated protection for multi-wire feeders.
• 400 A rating: Supports high-current feeders and main circuits within compatible panelboards, delivering robust protection without compromising performance.
• OEM compatibility: Designed to pair with matching Square D OEM loadcenters and panelboards for seamless installation and reliable operation.
• Versatile application: Suitable for residential, commercial, and light industrial environments where dependable branch circuit protection is essential.

Technical specifications

• Manufacturer: Square D
• Part Number: LLL36400U31X
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400 A
• Number of Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Whether you're upgrading an existing panel, designing a new electrical distribution system, or replacing a failed breaker, the Square D LLL36400U31X delivers dependable protection with OEM compatibility and smart space utilization. Invest in a proven protection solution—trust Square D, trusted by electricians and supported by AmpState.