MT3400T - 400 Amp Trip Unit

MT3400T - 400 Amp Thermal-Magnetic Trip Unit

Looking for dependable, high‑performance protection for your electrical systems? The Eaton MT3400T Trip Unit delivers just that—bringing superior safety and load‑handling capability when paired with the right breaker frame. It’s the ideal choice for homeowners and contractors who want peace of mind without the fuss.

Key Features and Benefits

• High‑Capacity Performance: With a 400 Amp rating, this trip unit handles demanding electrical loads with ease, as long as it's installed into a compatible frame.
• Dual Protection (Thermal & Magnetic): You get the best of both worlds: thermal protection for gradual overloads and magnetic protection for sudden faults—helping prevent damage from both slow and fast electrical issues.
• Balanced, Three‑Pole Design: Ensures consistent power distribution across all three phases, which means smoother performance and enhanced safety in multi‑phase setups.
• Tailored Fit for MDL & HMDL Series: Made to work flawlessly with MDL and HMDL frames in J‑K sizes (Series C), this unit slides right into the proper configuration without hassle.

Technical Specifications

• Current Rating: 400 Amp
• Trip Mechanism: Thermal‑Magnetic (combines two protection approaches)
• Poles: Three‑Pole
• Compatible Breaker Types: Eaton MDL and HMDL
• Frame Size / Series: J‑K Frame, Series C
• Dimensions:
  • Length: Approx. 7"
  • Height: Approx. 4"
  • Width: Approx. 4"
• Weight: Around 3 lb

Material Compliance and Certifications

• UL Listed: The MT3400T is UL Listed, which means it meets stringent safety and performance standards in North America. Just pair it with an approved MDL or HMDL frame, and you’ll have a full, code‑compliant circuit breaker that won’t let you—or your electrical system—down.

Suitability

• Need reliable protection for residential or commercial electrical setups? This trip unit shines in both environments. Use it in homes, small offices, or larger commercial spaces that require a 400 Amp solution. It’s particularly ideal when you want high‑quality overload and short‑circuit protection, without adding complexity.