Square D Q4L3400 400A 3P 240V Circuit Breaker | AmpState

Meet the Square D Q4L3400 from AmpState—a rugged 400 A, 3-pole, 240 V circuit breaker designed for everyday electrical work. This device is built for panelboards, load centers, and electrical distribution, delivering dependable protection where it counts.

For maintenance teams, panel builders, and inventory planners who require a precise part-number match, the Q4L3400 provides fast, reliable replacements with no guesswork. When you need the exact Square D component you can trust, this breaker keeps your system safeguarded while simplifying your procurement process.

Why this breaker stands out

• Exact part-number match: Q4L3400 is designed to fit Square D panelboards, load centers, and distribution panels, reducing compatibility headaches.
• High-capacity protection: 400 A line rating to handle demanding circuits with stable performance.
• Three-pole reliability: Robust three-pole design suitable for 240 V applications in distributed electrical systems.
• Inventory-friendly: A dependable spare that's easy to stock and quick to deploy when downtime matters.
• Direct-for-purpose use: Ideal for new builds, retrofits, and service call replacements where a precise, manufacturer-muscle match matters.

Key specifications

• Manufacturer: Square D
• Part Number: Q4L3400
• Product Type: Circuit Breaker
• Amperage: 400 A
• Poles: 3
• Voltage: 240 V

Ideal use cases

• Maintenance work where exact part-number compatibility saves time and reduces risk of misfits
• Panel builders incorporating reliable Square D components into distribution systems
• Spare inventory for service trucks and warehouses to minimize downtime on critical circuits
• Retrofits and upgrades in existing installations that require a precise 3P 240V protection device

Compatibility & installation tips

• Verify that your panelboard or load center supports a 3-pole, 240 V configuration with Square D breakers.
• Ensure mounting and bus compatibility align with standard Square D installation practices for 3P devices.
• Power down the system and follow all safety procedures during replacement to protect personnel and equipment.

Available from AmpState. Need help matching a part number or confirming compatibility? Message us and we’ll help you confirm fit.