ABB-S3N250 Circuit Breaker

   The ABB-S3N250 circuit breaker is a molded case circuit breaker (MCCB) in the ABB SACE-Isomax series, mainly used for the protection against overload, short circuit, and ground fault in low-voltage power distribution systems. The following is a detailed analysis based on the search resources:

I. Core Parameters and Performance

1. **Rated Current and Trip Unit**

   - **Frame Current**: 250A, supporting the adjustment of the trip unit current (such as models like R200, R250, etc.).

   - **Tripping Characteristics**: Using a thermal-magnetic trip unit (TM), with an instantaneous tripping multiple of 10 times the rated current (10Ith), which is suitable for the protection of power distribution lines and motors.

   - **Tripping Curve**: According to industry standards, the thermal-magnetic trip unit usually corresponds to type C (5-10 times the rated current) or type D (10-20 times). The specific details need to be confirmed in combination with ABB's official documents.

2. **Interrupting Capacity**

   - **Rated Ultimate Short-Circuit Breaking Capacity (Icu)**: 45kA (applicable to an AC 400V system).

   - **Rated Service Short-Circuit Breaking Capacity (Ics)**: 40kA, which can break the short-circuit current multiple times.

3. **Voltage and Number of Poles**

   - **Rated Insulation Voltage**: 690V, suitable for systems with an AC voltage below 400V.

   - **Number of Poles**: 3P (three-phase) or 4P (three-phase four-wire), supporting different grounding systems (such as TN-S, TN-C-S).

 II. Application Scenarios

1. **Industrial and Commercial Power Distribution* YouTube：https://youtube.com/shorts/2oZmg9c_OIs  *

   - Used for terminal power distribution in places such as factories, office buildings, and shopping malls to protect equipment such as motors, lighting circuits, and frequency converters.

   - Supports photovoltaic systems with the mode of "self-generation for self-use and surplus power fed into the grid", for example, providing short-circuit protection at the output of the combiner box or the inverter.

2. **Special Environments**

   - Suitable for high-dust or vibrating environments such as coal mines, railways, and ports, and needs to be used with dust-proof accessories.

   - The altitude should not exceed 2000 meters, the ambient temperature is between -5°C and +40°C, and the humidity does not exceed 90%.

III. Installation and Accessories

1. **Installation Method**

   - Fixed installation, supporting front-of-panel or rear-of-panel wiring, and the operation mode is a manual handle.

   - An optional electric operating mechanism (such as 1SDA013876R1) can be used to achieve remote control.

2. **Accessory Compatibility**

   - **Auxiliary Contacts**: Used to indicate the status of the circuit breaker (such as closed/open).

   - **Shunt Trip**: Supports remote tripping (such as linkage with a fire alarm).

   - **Undervoltage Trip**: Automatically trips when the voltage is lower than the set value.

   - **Leakage Protection Module**: Some models integrate a zero-sequence current transformer to provide ground fault protection.

 IV. Selection and Maintenance

1. **Selection Key Points**

   - **Load Matching**: The trip unit current (In) should be greater than or equal to the calculated load current (Ic) and less than the conductor's current-carrying capacity (Iz).

   - **Short-Circuit Capacity**: Select the interrupting capacity (Icu/Ics) according to the expected short-circuit current at the installation site.

   - **Environmental Conditions**: It needs to be derated for use in high-temperature or high-humidity environments.

2. **Maintenance Suggestions**

   - **Regular Inspection**: Clean the contacts and check whether the trip unit operates normally.

   - **Avoid Overload**: Long-term overload will accelerate the wear of the contacts and shorten the service life.

   - **Fault Handling**: After the short-circuit trip, check the ablation condition of the contacts and replace the circuit breaker if necessary.

 V. Market Status and Alternative Solutions

1. **Current Market**

   - The S3N250 is still on sale, with a price range of approximately 344 yuan to 1040 yuan, specifically depending on the trip unit model and accessory configuration.

   - The suppliers are mainly concentrated in China, such as Jiangsu Shilike, Quanzhou Zhongying Electric, etc.

2. **Alternative Models**

   - **ABB TMAX XT Series**: Such as XT3S250, which has a higher interrupting capacity (70kA) and supports electronic trip units and intelligent monitoring.

   - **Other Brands**: Schneider NSX series, Siemens 3WL series, etc., and the selection needs to be made by comparing the parameters.

VI. Official Resources and Support

- **Operation Manual**: It needs to be obtained through ABB's official website or authorized dealers, and the content covers installation, wiring, commissioning, and troubleshooting.

- **Certification Standards**: It has passed the CCC certification and complies with IEC 60898 (Circuit breakers for domestic and similar purposes) and IEC 60947-2 (Low-voltage switchgear and controlgear).

Conclusion

With its stable performance and flexible configuration, the ABB-S3N250 circuit breaker is suitable for a variety of low-voltage power distribution scenarios. When selecting the model, attention should be paid to the tripping characteristics, interrupting capacity, and accessory compatibility. If necessary, refer to ABB's official documents or contact technical support. If higher performance or intelligent functions are required, the TMAX XT series or alternative models of other brands can be considered.