Square D LDL36400U33X - 400 A, 600 V, 3-Pole Circuit Breaker | AmpState

Square D LDL36400U33X is a 400A, 600V, 3-pole molded case circuit breaker built to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and loadcenters. Designed to fit seamlessly with matching OEM panels, it’s a trusted choice for robust electrical protection in a range of settings.

Why this breaker stands out

• Space-efficient design — the compact molded case helps maximize panel occupancy, making room for additional circuits without sacrificing protection.
• Thermal-magnetic trip unit — delivers stable, repeatable protection performance, combining thermal overload protection with instantaneous magnetic response for fast short-circuit clearance.
• OEM compatibility — specifically designed to be compatible with matching Square D loadcenters and panelboards, ensuring a reliable, plug‑in fit and proper coordination within your panel.
• Versatile application — suitable for residential, commercial, and light industrial environments where a 400A, 3-pole device is required for 3‑phase systems up to 600V.

Ideal use cases

• Feeder protection in commercial panelboards where three‑phase circuits require solid overcurrent and short-circuit safeguards.
• Replacement or upgrade in existing Square D installations to maintain system coordination and panel integrity.
• New construction or retrofit projects that demand a compact, reliable 3‑pole breaker rated for higher current levels.

Technical specifications

• Manufacturer: Square D
• Part Number: LDL36400U33X
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400 A
• Voltage Rating: 600 V
• Number of Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Choosing the LDL36400U33X means prioritizing reliability and compatibility in your electrical protection strategy. For panel health and safety, pair this 3‑pole breaker with a matching Square D loadcenter or panelboard and verify voltage and phase requirements align with your installation. Ideal for professionals who value precise protection, predictable performance, and straightforward replacement in established Square D ecosystems.