1. Product Overview
The ABB Tmax XT4NU3250EFF000XXX is a high-performance molded case circuit breaker designed for reliable protection in various electrical systems. This device features a frame size XT4, rated for up to 250A, with voltage ratings of 600V (UL) and 690V (IEC). It incorporates an Ekip LS/I electronic trip unit, providing Long-Time (L), Short-Time (S), and Instantaneous (I) protection functions. This 3-pole circuit breaker is engineered for safety and efficiency in industrial and commercial applications.

An image showing the ABB Tmax XT4NU3250EFF000XXX Molded Case Circuit Breaker. The device is dark gray with a red and white handle, indicating its operational status. Various labels and connection points are visible on its front and sides.
2. Safety Information
Always observe the following safety precautions to prevent injury or damage to the equipment:
- Installation, maintenance, and repair must be performed by qualified personnel only.
- Ensure all power sources are disconnected and locked out before working on the circuit breaker or associated circuitry.
- Use appropriate personal protective equipment (PPE) such as insulated gloves, safety glasses, and arc-flash protective clothing.
- Verify correct voltage and current ratings before installation.
- Do not operate the circuit breaker if it appears damaged or malfunctioning.
3. Setup and Installation
The ABB Tmax XT4NU3250EFF000XXX circuit breaker is designed for DIN Rail Mount installation. Proper installation is crucial for safe and reliable operation.
3.1 Pre-Installation Checks
- Inspect the circuit breaker for any physical damage.
- Confirm that the product specifications match the system requirements.
- Ensure the mounting surface is clean and secure.
3.2 Mounting
- Securely attach the circuit breaker to a standard DIN rail.
- Ensure proper ventilation around the device to prevent overheating.
3.3 Wiring
- Connect the main power supply conductors to the appropriate terminals (Line/Load) as indicated on the device.
- Ensure all connections are tight and secure to prevent loose contacts and arcing.
- Follow all local and national electrical codes for wiring practices.
- Verify correct polarity and phase sequence for multi-phase installations.
4. Operating Instructions
The ABB Tmax XT4NU3250EFF000XXX circuit breaker is designed for straightforward operation.
4.1 Switching On/Off
- To Switch ON: Push the operating handle firmly to the 'ON' position.
- To Switch OFF: Push the operating handle firmly to the 'OFF' position.
4.2 Trip Indication and Reset
- If an overload or short-circuit occurs, the circuit breaker will automatically trip, moving the handle to an intermediate 'TRIPPED' position.
- To Reset: First, move the handle fully to the 'OFF' position. Then, push the handle to the 'ON' position.
- Before resetting, investigate and resolve the cause of the trip. Repeated tripping indicates an underlying electrical issue.
5. Maintenance
Regular maintenance ensures the longevity and reliable operation of your circuit breaker.
5.1 Routine Inspection
- Periodically inspect the circuit breaker for any signs of physical damage, discoloration, or loose connections.
- Check for dust accumulation and keep the area around the breaker clean.
5.2 Cleaning
- Ensure power is disconnected before cleaning.
- Use a dry, lint-free cloth to wipe down the exterior of the circuit breaker. Avoid using solvents or abrasive cleaners.
5.3 Professional Servicing
For internal inspection, testing, or repair, contact qualified ABB service personnel or an authorized service center. Do not attempt to disassemble the circuit breaker yourself.
6. Troubleshooting
This section provides guidance for common issues. For complex problems, consult a qualified electrician.
6.1 Breaker Trips Frequently
- Possible Cause: Overload.
- Action: Reduce the load on the circuit by unplugging some devices.
- Possible Cause: Short circuit.
- Action: Inspect wiring and connected devices for faults. This requires professional attention.
- Possible Cause: Ground fault (if applicable to the specific trip unit configuration).
- Action: Consult a qualified electrician to identify and rectify the ground fault.
6.2 Breaker Will Not Reset
- Possible Cause: Persistent fault (overload or short circuit).
- Action: Ensure the cause of the trip has been resolved. If the fault persists, the breaker will not reset.
- Possible Cause: Internal damage to the breaker.
- Action: If no fault is present and the breaker still won't reset, it may be damaged and require replacement by a qualified professional.
7. Specifications
Detailed technical specifications for the ABB Tmax XT4NU3250EFF000XXX Molded Case Circuit Breaker:
| Specification | Value |
|---|---|
| Brand | ABB |
| Model | XT4NU3250EFF000XXX |
| Current Rating | 250 Amps |
| Voltage Rating (UL) | 600V |
| Voltage Rating (IEC) | 690V |
| Trip Type | Ekip LS/I (Electronic, LS/I Protection) |
| Number Of Poles | 3 |
| Circuit Breaker Type | LS |
| Mounting Type | DIN Rail Mount |
| Package Dimensions | 8.26 x 6.49 x 6.1 inches |
| Weight | 5.51 Pounds |
| Date First Available | June 25, 2018 |
8. Warranty Information
ABB products are manufactured to high standards and typically come with a manufacturer's warranty. For specific warranty terms and conditions applicable to your ABB Tmax XT4NU3250EFF000XXX circuit breaker, please refer to the official documentation provided with your purchase or visit the official ABB website. Keep your proof of purchase for warranty claims.
9. Support and Contact
For technical assistance, product inquiries, or service requests, please contact ABB customer support. You can find contact information and additional resources on the official ABB website.
ABB Official Website: Visit the ABB Store on Amazon
Always provide the full model number (XT4NU3250EFF000XXX) when contacting support to ensure accurate assistance.





