Overview
The Eaton KT3400T thermal magnetic trip unit is an accessory component for Series C molded case circuit breakers. Rated at 400 amperes with 3-pole configuration and K-frame mounting, this unit delivers proven protection against sustained overloads and instantaneous short circuits. It features Long-Time and Instantaneous (LI) trip functions and is field-installable for system integrators and maintenance technicians.
Key Features
- Thermal magnetic protection: Combines thermal trip sensing for overloads with magnetic trip sensing for immediate short-circuit response.
- 400A rated current: Handles high-load industrial and commercial applications.
- 3-pole, K-frame design: Standard configuration for three-phase power systems in Series C breaker families.
- Interchangeable design: Field-installable trip unit allows maintenance and replacement without full breaker assembly swap.
- Adjustable magnetic trip: Magnetic trip range adjustable 5–10 times the continuous ampere rating.
- UL/CSA certified: Meets electrical safety and performance standards for North American installation.
Technical Specifications
- Catalog Number: KT3400T
- Ampere Rating: 400A
- Voltage Rating: 600 VAC
- Trip Configuration: 3-pole
- Trip Type: Thermal magnetic
- Frame Size: K-frame
- Series: Series C
- Trip Functions: Long-Time and Instantaneous (LI)
- AIC Rating: 65k @ 480 VAC
- Thermal Trip Range: 315–400A
- Magnetic Trip Range: 2000–4000A (adjustable)
- Dimensions: 6.9 in H × 4.2 in W × 5.4 in D
- Weight: 1.95 lbs
- Certifications: UL, CSA
Typical Applications
The KT3400T serves power distribution, motor control, and branch circuit protection in:
- Industrial manufacturing and processing plants
- Commercial building electrical systems and data centers
- Heavy equipment and machinery control circuits
- Three-phase power distribution panels
- Retrofit and field upgrade installations for Series C breaker housings
Compatibility & Replacements
Compatible With
- Eaton Series C molded case circuit breaker frame types: DK, KD, KDB, HKD, HKDDC, HKDB, KDC, CKD, CHKD, KG
- K-frame 400A circuit breaker housings (2-pole and 3-pole configurations)
- Standard three-phase power distribution systems up to 600 VAC
- Industrial electrical control and protection networks
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering to confirm the existing breaker frame and configuration match the K-frame, Series C specification. The KT3400T is designed as a direct replacement for compatible Series C breaker housings where thermal magnetic trip protection is required.
Works With
- Eaton Cutler-Hammer molded case circuit breaker assemblies (Series C)
- Industrial control systems and electrical panels rated 600 VAC
- Standard electrical installation and maintenance practices per National Electrical Code (NEC)
- Field service and retrofit upgrade applications in existing power distribution infrastructure
