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Phone: +86 16626708626Description
3. Key Technical Specifications
| Parameter | Value |
|---|---|
| Catalog Number | KT3315TA |
| Type | Thermal-magnetic trip unit (adjustable) |
| Number of Poles | 3 |
| Continuous Ampere Rating | 315 A (at 40 °C) |
| Thermal Trip Range | 250 – 315 A (adjustable) |
| Magnetic Trip Range | 1575 – 3150 A (adjustable) |
| Voltage Rating | Up to 600 VAC |
| Compatible Frames | Series C K-Frame (also used with J-K) |
| Trip Type | Adjustable thermal + adjustable magnetic |
| Application | Interchangeable trip unit for MCCBs |
| Certifications | UL Listed |
4. Product Introduction
The Eaton KT3315TA is a 3-pole adjustable thermal-magnetic trip unit designed for Series C K-Frame molded case circuit breakers. It provides both inverse-time thermal overload protection and instantaneous magnetic short-circuit protection.
The continuous rating is 315 A. Thermal pickup is adjustable from 250 A to 315 A; magnetic pickup is adjustable from 1575 A to 3150 A (typically 5–10 times continuous rating). The unit is fully interchangeable within compatible K-Frame (and certain J-K) breakers, allowing rating changes or replacement without replacing the entire breaker frame.
KT3315TA
KT3315TA
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Breaker will not close | Trip unit not fully seated | ✅ High | Verify trip unit is locked in place and contacts align | Reseat trip unit per Eaton installation instructions |
| Nuisance thermal trips | Thermal setting too low | ✅ High | Check thermal adjustment dial position | Raise thermal setting within allowed range |
| Fails to trip on short circuit | Magnetic setting too high or unit fault | ✅ High | Compare magnetic dial setting to application requirements | Adjust magnetic range or replace trip unit |
| Breaker trips immediately on close | Internal short or wrong rating | ✅ Medium | Verify continuous rating matches load and frame | Confirm correct trip unit catalog number |
| Inconsistent trip times | Damaged thermal element | ✅ High | Compare trip times against published curves | Replace trip unit; do not attempt field repair |
| No trip function after install | Missing or damaged trip unit | ✅ High | Visual inspection of trip unit installation | Install genuine Eaton KT3315TA only |
If the breaker frame itself is suspect, test with a known-good trip unit before condemning the frame. Always follow lockout/tagout and manufacturer procedures.
6. Frequently Asked Questions (FAQ)
Q: What breakers does the KT3315TA fit?
It is designed for Eaton Series C K-Frame molded case circuit breakers. It is also listed for certain J-K frame applications. Always verify frame compatibility before ordering.
Q: Is the thermal rating fixed or adjustable?
Adjustable. Thermal continuous range is 250–315 A. Magnetic range is 1575–3150 A.
Q: Can I use this trip unit in a different ampere frame?
No. Use only in frames rated for the 315 A continuous rating. Installing an incorrect trip unit can result in improper protection or damage.
Q: Is the KT3315TA still available new?
Yes. Genuine Eaton units remain available as new or new-surplus stock. We supply only verified OEM parts.
Q: Do I need any tools or adapters to install it?
Standard installation follows the Eaton K-Frame trip unit procedure. No special adapters are required for standard 3-pole applications. Always de-energize and follow the official installation leaflet.
Q: What is the difference between fixed and adjustable thermal versions?
The “TA” suffix indicates adjustable thermal. Fixed-thermal versions use a different catalog number (for example KT3315T). Choose the version that matches your original design or coordination study.
Install the correct trip unit, set the dials to the values specified by the coordination study, and the breaker will provide reliable overload and short-circuit protection.
