Square D | Q422400AC | Circuit Breaker | 400A | 2-Pole | 25kA

Meet the Square D Q422400AC circuit breaker—a purpose-built solution for demanding electrical systems where precise protection matters. This 400A, 2-pole unit brings dependable interruption capability (25kA) to maintenance, retrofit, and replacement projects, ensuring quick isolation of faults and minimal downtime.

Key specifications

• Amperage: 400A
• Poles: 2-Pole
• Interrupt rating: 25kA
• Part number: Q422400AC

Why this breaker matters

In systems where high fault currents are a reality, the Q422400AC delivers robust protection by interrupting dangerous conditions swiftly. Its two-pole design provides coordinated protection for both legs of a circuit, helping safeguard equipment, reduce arc-flash risk, and support safer maintenance procedures in service entrances, feeders, and panel boards.

Who it's ideal for

• Facility managers overseeing retrofit and upgrade projects in commercial or light industrial settings
• Electrical contractors replacing aging or non-matching breakers in existing Square D installations
• Maintenance teams seeking a reliable, high-capacity solution for critical power distribution

Use cases and scenarios

• Replacement of a failed or incompatible breaker in a 400A service panel
• Retrofits where new equipment requires matching 2-pole 400A protection with a 25kA interrupt rating
• Direct substitution in systems designed around Square D Q-series protection devices

Fit, compatibility, and buying confidently

Before ordering, confirm the fit and ratings match your panel or distribution equipment. The part number Q422400AC is the most reliable reference for compatibility within Square D installations. If your panel model accepts a 400A, 2-pole breaker with a 25kA interrupt rating, this unit is a strong match.

Installation and safety notes

Follow standard electrical safety practices and local codes when replacing or installing this breaker. Ensure the power is fully shut off and that proper lockout/tagout procedures are in place. For optimal performance, verify that the panel labeling and field wiring align with the breaker’s specifications and torque requirements.