Overview
The Eaton Cutler-Hammer KT3400T is an interchangeable thermal magnetic trip unit designed for Series C molded case circuit breakers with K-frame configuration. Rated for 400 amps continuous at 40°C and 600VAC operation, this 3-pole trip unit combines thermal and magnetic protection mechanisms to detect both sustained overloads and instantaneous short circuits. The KT3400T is field-installable and provides adjustable trip parameters for precise protection coordination in industrial, commercial, and institutional power systems.
Key Features
- Thermal magnetic trip technology for combined overload and short-circuit protection
- 3-pole configuration for three-phase power distribution
- Interchangeable design—field installable in compatible breaker frames
- Adjustable long-time trip range: 315–400A
- Adjustable instantaneous magnetic trip: 5–10 times continuous ampere rating
- UL and CSA approved for North American electrical codes
Technical Specifications
- Continuous Ampere Rating: 400A @ 40°C
- Voltage Rating: 600VAC
- Short Circuit Rating: 65,000A @ 480VAC
- Frame Type: K (K-frame)
- Number of Poles: 3-pole
- Trip Type: Thermal Magnetic
- Thermal Trip Range: 2000–4000A (adjustable)
- Magnetic Trip Adjustment: 5–10× continuous ampere rating
- Weight: 1.95 lb
- Certifications: UL, CSA, CE
Typical Applications
The KT3400T is suitable for use in:
- Commercial and institutional electrical power distribution
- Industrial control panels and motor control centers
- Emergency backup and standby power systems
- Feeder and branch circuit protection
- Equipment protection in facilities requiring precise coordination
Compatibility & Replacements
Compatible With
- Eaton Cutler-Hammer Series C molded case circuit breakers
- K-frame breaker configurations (DK, KD, KDB, HKD, HKDDC, HKDB, KDC, CKD, CHKD, KG frames)
- 2-pole and 3-pole circuit breaker assemblies
- 4-pole circuit breaker configurations with neutral adapter
Replaces / Drop-In Replacement For
- KT3400TA (adjustable thermal version)
- Other OEM interchangeable trip units for 400A K-frame applications
Works With
- Standard North American molded case circuit breaker frame designs
- Eaton electrical protection accessories (shunt trips, undervoltage releases, auxiliary switches)
- Three-phase power distribution systems operating at 600VAC or lower
