Square D 9421LJ1 250A 3P Circuit Breaker | AmpState

Meet Square D 9421LJ1, a purpose-built 250A 3-pole circuit breaker engineered for dependable circuit protection in panelboards, load centers, and electrical distribution networks. This part is ideal for replacement projects and for stocking spare units when you need to keep your bill of materials (BOM) aligned with the original part number. Available from AmpState.

Why this 9421LJ1 stands out

• Precisely rated for 250 A, delivering reliable overcurrent protection for demanding electrical circuits
• Three-pole design provides robust control across 3-phase systems and protects multiple conductors with a single device
• Square D compatibility ensures consistent performance with existing panelboards and distribution equipment
• Stocking this part helps maintain BOM integrity, reducing potential delays when replacements are required
• Support from AmpState to confirm fit: if you need help matching a part number or verifying compatibility, our team can assist

Key specifications

• Manufacturer: Square D
• Part Number: 9421LJ1
• Product Type: Circuit Breaker
• Amperage: 250 A
• Poles: 3

Ideal use cases

Whether you’re maintaining commercial facilities, upgrading electrical distribution, or conducting routine panel maintenance, the 9421LJ1 is designed to slot into existing Square D systems with minimal disruption. Its 3-pole setup is especially well-suited for 3-phase environments, delivering coordinated protection across phases and helping prevent nuisance trips in balanced loads.

Practical considerations

For projects that require exact BOM alignment and seamless compatibility, this 9421LJ1 matches the original specification without modification. When evaluating alternatives, consider whether the part preserves the original protection scheme, mounting geometry, and bus compatibility. This unit emphasizes alignment with Square D distribution infrastructure to reduce the risk of misfits and installation delays.

Reliable support

Need help confirming fit or matching a part number? Message us and we’ll help you confirm compatibility so you can buy with confidence.