Siemens 4MLKA3B 400A Circuit Breaker | AmpState

Siemens 4MLKA3B is a 400 A circuit breaker designed to deliver dependable protection in panelboards, load centers, and broader electrical distribution layouts. Built to stand up to demanding commercial and industrial environments, this device helps safeguard downstream circuits while keeping your main distribution running smoothly.

• Exact OEM part for BOM integrity – The 4MLKA3B part number ensures your replacement aligns perfectly with original schematics and maintenance documentation, preserving system compatibility and documentation accuracy.
• Replacement-ready for downtime minimization – Ideal for replacement projects where maintaining the original equipment configuration matters, and for stocking spares to speed service restoration.
• High-current protection – Rated at 400 A, this breaker is suited for protecting main feeders and critical distribution paths in larger panelboards and electrical distribution systems.
• Trusted source – Available from AmpState, providing a reliable supply channel for hard-to-find Siemens components and compatible spare parts.
• Compatibility support – If you’re unsure about fit, just reach out: we can help you confirm compatibility with your panel or distribution setup to ensure a seamless install.

Who this is for: electrical contractors, facilities managers, and maintenance teams maintaining commercial or light-industrial buildings where precise part-number compatibility and reliable protection matter. This is the choice for projects that require sticking with the original Siemens design while ensuring pop-in readiness and easy BOM management.

Key details to know:

• Manufacturer: Siemens
• Part Number: 4MLKA3B
• Amperage: 400 A

If you need help verifying fit or confirming compatibility with your panelboard, load center, or distribution scheme, send us a message and our team will assist in confirming the right application for your system.