Square D | A1B345 | Circuit Breaker | 45A | 3-Pole | 240V

Square D A1B345 Circuit Breaker is a dependable protection solution designed for maintenance, retrofit, and replacement projects where exact specifications matter. This 45A, 3-Pole, 240V breaker is built to integrate smoothly into compatible Square D installations, delivering consistent performance when you need to safeguard power distribution.

Key specifications at a glance

• Amperage: 45 A
• Poles: 3-Pole
• Voltage: 240V
• Part number: A1B345
• Type: Square D protective device

Why this specific model stands out

• Exact compatibility through the part number: The A1B345 designation is your best reference to ensure a proper fit and electrical ratings within Square D panels.
• Targeted for retrofit and replacement: Designed for scenarios where a like-for-like swap is needed to restore protected circuits without altering panel configurations.
• Clear electrical characteristics: 45A rating on a 240V circuit provides robust overcurrent protection for appropriate loads while preserving overall system performance.

Practical use cases

• Replacing a worn or failed 45A, 3-Pole breaker in existing Square D panels to minimize downtime.
• Retrofit projects where a legacy 3-Pole 240V device must be substituted with a compatible part using the A1B345 reference.
• Maintenance planning for facilities with standardized Square D components, ensuring consistent protection across distributed circuits.

Fit, rating, and ordering guidance

Before purchasing, verify that your panel accepts the A1B345 and that the circuit demands align with 45A on a 240V supply. The part number A1B345 is the most reliable compatibility reference, helping you avoid misfits and ensure proper trip characteristics. If in doubt, compare the panel label and the existing breaker’s specifications to this model to confirm a seamless replacement.

How this compares to alternatives

This Square D solution is purpose-built to match the brand’s mounting geometry, terminal styles, and trip curves for consistent protection within compatible systems. It’s designed for straightforward replacement without adapters or panel reconfigurations, reducing install time and risk associated with cross-brand substitutions.

Tips for installation and safety

• Always de-energize the panel and follow lockout/tagout procedures before work.
• Inspect the bus stab and mounting point for clean, undamaged contact surfaces to ensure reliable operation.
• Keep a spare A1B345 on hand for planned maintenance windows or urgent replacements, aligning with your panel’s standard component set.