Eaton MDL3400 - 400 A, 600 V, 3-Pole Circuit Breaker | AmpState

The Eaton MDL3400 is a purpose-built 3-pole molded case circuit breaker rated at 400 A and 600 V, engineered for dependable branch-circuit overcurrent and short-circuit protection in panelboards and load centers. This compact unit delivers precise protection where space and reliability matter most, making it a smart choice for modern electrical systems.

Why the MDL3400 stands out

• Compact molded case design optimizes panel space without compromising amperage or protection, helping you nail clean, efficient installations in tight panels.
• Thermal-magnetic trip unit provides stable, repeatable protection across varying loads and temperatures, reducing nuisance trips while maintaining rapid response to overcurrents and short circuits.
• OEM-compatible built to pair with matching Eaton OEM loadcenters and panelboards, enabling quick, straightforward replacements or upgrades with consistent fit and performance.
• Versatile applications suited for residential, commercial, and light industrial environments where reliable 400 A protection is required across three phases.
• Three-pole synchronization ensures coordinated disconnection across all phases for balanced protection and safer fault clearance.

Technical snapshot

• Amperage rating: 400 A
• Voltage rating: 600 V
• Number of poles: 3
• Type: Thermal-magnetic molded case circuit breaker
• Part number: MDL3400
• Application: Branch circuit overcurrent and short-circuit protection

Ideal use cases

• Upgrading panelboards in commercial spaces that require robust 400 A branch protection with a reliable trip mechanism
• Feeding subpanels in light industrial facilities where three-phase protection and quick, predictable disconnection are critical
• Residential-commercial mix installations that demand durable protection for large, multi-wire branch circuits

What this means in practice

The MDL3400 doesn't just meet the basics of overcurrent protection—it delivers consistent performance in real-world conditions. The thermal-magnetic technology adapts to load fluctuations, while the compact form factor simplifies panel layouts and reduces installation time. If you’re stocking a panel upgrade or refurbishing a panelboard, this breaker aligns with Eaton’s OEM ecosystem, helping you maintain compatibility and streamline maintenance.

Choose the Eaton MDL3400 for a dependable, three-pole solution that balances space efficiency, protection reliability, and ease of integration in residential, commercial, and light industrial electrical systems.