Chint NXB125-3P100A miniature circuit breaker

Chint NXB125-3P100A is a 3-pole miniature circuit breaker suitable for 400V AC power distribution systems. It is mainly used for overload protection, short-circuit protection and line isolation.

 I. Core Technical Parameters

1. Basic Specifications

- **Pole Number**: 3P (Three-pole), suitable for three-phase four-wire or three-phase three-wire circuits.

- **Rated Current**: 100A, with a frame rating current of 125A, which can meet the power distribution requirements of high-load scenarios.

- **Tripping Characteristics**: Divided into Type C (for conventional loads, electromagnetic tripping multiple: 8-12In) and Type D (for inductive loads such as motor starting, tripping multiple: 10-14In). The selection should be based on the actual load type.

- **Breaking Capacity**: 10kA (rated ultimate short-circuit breaking capacity ICU), in line with GB/T 14048.2 and IEC 60947-2 standards, capable of handling sudden short-circuit faults.

- **Rated Voltage**: 400V AC, frequency 50Hz, compatible with industrial and civil power distribution systems.

2. Mechanical and Electrical Life

- Mechanical life: 20,000 operations; Electrical life: 6,000 operations (when In ≤ 100A), ensuring high stability during long-term use.

- Overall dimensions: Approximately 81mm × 78.5mm × 80mm; Weight: 0.6kg. It adopts 35mm standard DIN rail mounting, which saves space and facilitates maintenance.

3. Certifications and Standards

- It has obtained CCC and CE certifications, complies with international safety specifications, and is applicable to domestic and overseas engineering scenarios.

 II. Typical Application Scenarios

1. Industrial Power Distribution

- Used for protection of motor control circuits and power incoming lines of production equipment. The Type D tripping characteristic can withstand the instantaneous inrush current during motor starting.

- For example, in small and medium-sized factories, it can be used as the main circuit breaker for 380V three-phase equipment (such as fans and water pumps).

2. Commercial and Civil Buildings

- Suitable for three-phase distribution boxes in office buildings, shopping malls and other places, used to protect branch circuits such as lighting and air conditioning.

- For household users with three-phase power supply access (such as villas or scenarios with concentrated high-power electrical appliances), it can be used as the main incoming line circuit breaker.

3. Temporary Power Supply and Construction

- In temporary distribution boxes at construction sites, it can prevent cable overheating caused by overload and improve electrical safety.

 III. Selection and Installation Recommendations

1. Selection Notes

- **Load Matching**: Type C is suitable for resistive loads (such as heating equipment), and Type D is suitable for inductive loads (such as motors) to avoid false tripping.

- **Environmental Conditions**: Operating temperature range: -5℃ ~ +40℃; Altitude: ≤ 2000 meters. It should not be used in humid or dusty environments.

2. Installation Key Points

- It is fixed using a TH35mm DIN rail. Ensure the rail is installed firmly and reserve heat dissipation space (with a spacing of ≥ 10mm).

- When wiring, tighten the terminal screws (torque: 2.5N·m) to avoid heating caused by poor contact.

3. Price and Purchase Channels

- The market price is approximately 35 RMB ~ 132 RMB per unit. For bulk purchases (e.g., more than 10 units), the price can be as low as 32 RMB per unit, which varies depending on the purchase channel and promotional activities.

 IV. User Reviews and Alternative Solutions

1. Practical Usage Feedback

- Most users comment that it has "solid hand feel and clear opening/closing operation", and its price is more competitive than that of international brands such as Schneider and ABB, featuring outstanding cost-effectiveness.

- It should be noted that counterfeit products may exist in some channels. It is recommended to purchase through officially authorized distributors.

2. Alternative Model Reference

- **Upgrade Option**: If higher breaking capacity (e.g., 15kA) is required, Chint NXMN series molded case circuit breakers can be considered, which are compatible with 3P design and have higher short-circuit withstand capacity.

- **Economical Option**: Delixi DZ47-125 series 3P 100A circuit breakers are slightly cheaper (about 28 RMB per unit) with a breaking capacity of 10kA, which can be used as alternatives.

 V. Safety and Maintenance Tips

1. Regular Inspection

- Check whether the terminal blocks are loose every six months, and test the insulation resistance with an insulation resistance tester every year (the insulation resistance should be ≥ 1MΩ).

- If the circuit breaker trips frequently, check whether the load is overloaded or if there is a short-circuit fault in the line.

2. Fault Handling

- After tripping due to overload, wait for 1-2 minutes to allow the bimetallic strip to cool down before closing the circuit breaker.

- After tripping due to short-circuit, the fault point must be eliminated first to avoid secondary damage caused by direct closing.

In conclusion, Chint NXB125-3P100A has become a mainstream choice for three-phase power distribution scenarios due to its high cost-effectiveness, reliable performance and wide compatibility. It is recommended to select the product reasonably according to the actual load characteristics and installation environment, and purchase through formal channels to ensure product quality.