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Phone: +86 16626708626Description
3. Key Technical Specifications
| Parameter | Value |
|---|---|
| Catalog Number | KW3400 |
| Type | Complete molded case circuit breaker |
| Frame | K-Frame |
| Number of Poles | 3 |
| Continuous Ampere Rating | 400 A |
| Voltage Rating | 600 Vac / 250 Vdc |
| Interrupt Rating | 45 kAIC at 415 Vac |
| Trip Type | Adjustable thermal, adjustable magnetic |
| Terminals | Line and load |
| Class | World / IEC |
| Series | Series C |
| Circuit Breaker Type | KW |
4. Product Introduction
The Eaton KW3400 is a complete 3-pole Series C K-Frame molded case circuit breaker. It combines the K-frame with an adjustable thermal-magnetic trip unit and line/load terminals in one assembly.
Rated 400 A continuous, the breaker is suitable for 600 Vac and 250 Vdc systems and carries a 45 kAIC interrupt rating at 415 Vac. The thermal element is adjustable for overload protection and the magnetic element is adjustable for short-circuit protection. It is designed for panelboards, switchboards, motor control centers, and similar industrial applications where IEC/World-rated performance is required.
KW3400
KW3400
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Breaker will not close | Trip unit or mechanism issue | ✅ High | Verify handle position and trip unit seating | Reset fully; inspect for internal damage |
| Nuisance thermal trips | Thermal setting too low or overload | ✅ High | Check thermal dial and actual load current | Raise thermal setting or reduce load |
| Fails to clear short circuit | Magnetic setting too high | ✅ High | Compare magnetic dial to coordination study | Lower magnetic setting within allowed range |
| Breaker trips on energization | Downstream fault or wrong rating | ✅ Medium | Isolate load and re-test | Verify application matches 400 A rating |
| Overheating at terminals | Loose or undersized connections | ✅ High | Torque check and infrared scan | Re-torque to Eaton specifications |
| No trip function | Damaged trip unit | ✅ High | Functional test with known load or test set | Replace complete breaker or trip unit as required |
Always follow lockout/tagout procedures. If the frame is suspect, test with a known-good trip unit before condemning the entire breaker.
6. Frequently Asked Questions (FAQ)
Q: Is the KW3400 a complete breaker or just a frame?
It is a complete breaker (frame + trip unit + terminals). The frame-only version is cataloged as KW3400F.
Q: What is the interrupt rating?
45 kAIC at 415 Vac. Confirm system short-circuit levels before application.
Q: Are the thermal and magnetic settings adjustable?
Yes. Both the thermal (overload) and magnetic (short-circuit) elements are adjustable within the ranges specified for the 400 A rating.
Q: Can this breaker be reverse-fed?
Standard KW3400 is not listed as reverse-feed capable. Use an engine-generator or reverse-feed rated version if reverse feeding is required.
Q: Is the KW3400 still available new?
Yes. Genuine Eaton units remain available as new or new-surplus stock. We supply only verified OEM parts.
Q: What terminals are included?
Line and load terminals are included with the complete KW3400 breaker. Confirm wire size range matches your conductors.
Install according to the Eaton Series C installation instructions, set the trip dials to the values required by the coordination study, and the breaker will provide reliable overload and short-circuit protection.
