Eaton LT3400FA - 400 A, 600 V, 3-Pole Circuit Breaker | AmpState

The Eaton LT3400FA is a high-capacity, 3-pole molded case circuit breaker engineered to protect large branch circuits with precision. With a 400 A rating and a 600 V maximum, this device delivers reliable overcurrent and short-circuit protection inside panelboards and loadcenters, making it a trusted choice for demanding electrical distributions in residential, commercial, and light industrial settings.

Why the LT3400FA stands out

• Compact molded case design maximizes interior panel space, allowing you to fit high-current protection where it’s needed without crowding the enclosure.
• Thermal-magnetic trip unit provides stable, repeatable protection across a wide range of temperatures and load conditions, reducing nuisance trips and preserving downstream equipment.
• OEM-loadcenter compatibility is built to pair seamlessly with matching Eaton panelboards and loadcenters for straightforward installation and reliable long-term performance.
• Three-phase protection with a 400 A rating is ideal for feeders and large branch circuits in commercial and light industrial applications, while still suitable for higher-demand residential panel configurations when three-phase distribution is present.

Technical snapshot

• Manufacturer: Eaton
• Part Number: LT3400FA
• Type: Thermal-magnetic molded case circuit breaker (MCCB)
• Amperage: 400 A
• Voltage: 600 V
• Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Ideal use cases

Deploy the LT3400FA in installations that demand robust high-current protection without sacrificing space or compatibility. It’s well-suited for:

• Large feeders for three-phase equipment in commercial buildings, warehouses, and light industrial facilities.
• Upgrade projects where panel space is at a premium but the protection level must keep pace with growing electrical loads.
• Residential panelboards or subpanels in homes with three-phase service or sizable, high-demand electrical loads.
• Applications requiring dependable branch circuit protection that aligns with Eaton’s panelboard ecosystems.

Installation and compatibility considerations

To ensure optimal performance, pair the LT3400FA with matching Eaton OEM loadcenters and panelboards. This alignment guarantees coordinated trip characteristics and mechanical compatibility, helping streamline commissioning and ongoing maintenance. When integrating, consider the following practical points:

• Verify the panel rating and ensure a correct fit within the enclosure’s allowable current and space class.
• Leverage the thermal-magnetic trip to achieve predictable protection across daily operating conditions and ambient temperature variations.
• Use as a main feeder or a critical protection device for large branches, ensuring downstream conductors and devices are rated for 600 V and 400 A as appropriate.

The Eaton LT3400FA is more than a heavy-duty breaker—it’s a purpose-built solution for reliable, efficient power distribution. By combining a compact form factor, precise thermal-magnetic protection, and seamless compatibility with Eaton’s panel ecosystems, it helps you design safer, more resilient electrical systems that stand up to rigorous commercial and industrial use while still serving sophisticated residential applications where three-phase protection is required.