Chint NXMLE-100S/4300A-100A molded case residual current circuit breaker

Chint NXMLE-100S/4300A-100A is a molded case residual current circuit breaker (RCB), mainly used for overload protection, short-circuit protection, residual current protection, and infrequent line switching in low-voltage power distribution systems.

 I. Model Meaning and Core Parameters

1. Model Interpretation

NXMLE: Chint's series designation for molded case residual current circuit breakers.

125S: Frame current of 125A, breaking capacity of 25kA (Class S).

4300A: Four-pole structure (3P+N). The N pole is not equipped with an overcurrent release, remains permanently connected, and switches on/off synchronously with the other three poles.

100A: Rated current of 100A, suitable for a load power of approximately 44kW (AC 400V).

2. Core Parameters

Residual Current Protection: Two selectable ranges are available: 30-50-100mA (for residential/commercial scenarios) or 100-200-300-500mA (for industrial scenarios), with an operating time of ≤0.1 seconds.

Breaking Capacity: Ultimate short-circuit breaking capacity of 25kA, suitable for power distribution systems with low short-circuit current.

Trip Unit Type: Thermal-magnetic trip unit, providing both long-time delay protection against overload and instantaneous protection against short-circuit.

Rated Voltage: AC 400V/415V (for 3P/4P configurations), compliant with the GB 14048.2 standard.

 II. Functional Features and Application Scenarios

1. Safety Protection Functions

Residual Current Protection: When the residual current in the line exceeds the set value, the circuit breaker trips immediately to prevent electric shock and electrical fires.

Overload/Short-Circuit Protection: The thermal-magnetic trip unit automatically adjusts the operating time according to the current magnitude to avoid equipment damage.

Under-Voltage Protection: An optional under-voltage release (to be ordered separately) is available, which disconnects the circuit when the voltage drops below the set value.

2. Structural Design

Four-Pole Design: Adopts a 3P+N structure. The N pole is only used for neutral wire connection, does not participate in overcurrent protection, and ensures stability when the three-phase load is balanced.

Dual Protection: Features double protection with an upper cover and a middle cover, achieving an IP30 protection rating (excluding terminals), and is suitable for complex environments with dust or humidity.

Installation Method: Fixed installation with front-panel wiring, supporting both vertical and horizontal installation.

3. Typical Applications

Residential and Commercial Power Distribution: Suitable for main incoming line protection in household distribution boxes and small commercial stores, providing residual current and overload protection.

Industrial Control: Used for short-circuit protection in motor control circuits or as a protection switch for branch circuits.

Temporary Power Supply: Provides power protection for construction sites and temporary equipment to prevent residual current and short-circuit accidents.

 III. Market Price and Purchase Recommendations

1. Price Reference

Whatsapp: 0086-13811255435. The reference price is approximately 661 RMB per unit (packaged as 1 unit/box, 16 units/carton). For bulk orders, the price is about 300-400 RMB per unit.

2. Purchase Notes

Model Confirmation: Ensure the model is NXMLE-125S/4300A-100A to avoid confusion with similar models (e.g., NXMLE-125S/4310A is a 3P+N model with an alarm function).

Residual Current Selection: For household use, the 30-50-100mA range is preferred; for industrial scenarios, the 100-200-300-500mA range is recommended.

Alternative Model: If the above model is out of stock, NM1LE-125S/4300A-100A (with a breaking capacity of 30kA and a price of approximately 268 RMB) can be used as a substitute. However, it is necessary to confirm the compatibility of installation dimensions and parameters.

 IV. Installation and Maintenance Key Points

1. Installation Specifications

Wiring Requirements: Connect the power supply to the incoming terminal and the load to the outgoing terminal. The N pole must be connected to the neutral wire, and mixing it with the ground wire is strictly prohibited.

Installation Space: Sufficient clearance (≥20mm) must be reserved to ensure heat dissipation and operational safety. Vertical installation is recommended to facilitate arc extinction.

Insulation Testing: Before installation, use a 500V megohmmeter to test the insulation resistance, which should be ≥10MΩ to prevent damage to the electronic circuit board.

2. Daily Maintenance

Regular Inspection: Press the "test button" monthly to test the residual current function, and check whether the terminal blocks are loose annually.

Environment Monitoring: Avoid using the product in environments with high temperature (>40℃), high humidity (>90%RH), or corrosive gases.

Troubleshooting: After tripping, troubleshoot the fault before closing the circuit again. If frequent tripping occurs, check whether the line insulation is intact or if the load is overloaded.

 V. Certification and Technical Support

1. Certification Information

- Has passed the CCC Certification (Certificate No.: 202407...), and complies with the GB 14048.2 and IEC 60947-2 standards.

- Some models have obtained CE and CB Certifications, making them suitable for export projects.

 Summary

Chint NXMLE-100S/4300A-100A is a cost-effective residual current circuit breaker, suitable for various low-voltage power distribution scenarios. During model selection and use, it is necessary to select the residual current range according to actual load requirements, strictly follow the installation specifications, and perform regular maintenance to ensure safe and reliable operation. If a substitute model is needed, priority can be given to the NM1LE series of the same brand, but attention should be paid to parameter differences.