Chint NXB-63 Series Miniature Circuit Breakers

 The Chint NXB-63 series miniature circuit breakers are high-performance low-voltage power distribution protection devices, suitable for circuit overload and short-circuit protection in residential, commercial, and industrial fields. The following is a detailed analysis of its core parameters, functional features, and application scenarios:

 I. Model Analysis and Core Parameters

1. **Model Structure**

   - **NXB-63**: Represents the Chint Kunlun series miniature circuit breaker. The frame current is **63A**, which is suitable for the protection of medium and small power circuits.

   - **Number of Poles**: Supports configurations of **1P, 2P, 3P, 4P** and **1P+N, 3P+N**, meeting the requirements of single-phase, three-phase, and circuits with a neutral wire.

   - **Tripping Characteristics**:

     - **Type B**: Suitable for pure resistive loads (such as lighting and heating equipment), with a tripping curve of **3-5 times In**.

     - **Type C**: General-purpose type, suitable for mixed loads (such as sockets and small motors), with a tripping curve of **5-10 times In**.

     - **Type D**: Power type, suitable for high-impact loads (such as air conditioning compressors and transformers), with a tripping curve of **10-14 times In**.

   - **Interrupting Capacity**:YouTube：https://youtube.com/shorts/rcirptnxLHU 

     - **NXB-63**: **6kA (400V AC)**, meeting the needs of ordinary residential and commercial scenarios.

     - **NXB-63H**: **10kA (400V AC)**, suitable for industrial and high short-circuit current environments.

2. **Key Technical Parameters**

   - **Rated Voltage**: **230/400V AC** (single-phase/three-phase).

   - **Rated Current**: **1A to 63A** (covering a wide range of loads from lighting to small motors).

   - **Electrical Life**: **20,000 times** (under AC-3 load).

   - **Protection Level**: **IP20**, preventing fingers from touching the internal live parts.

   - **Ambient Temperature**: **-35°C to +70°C**, adapting to a wide-temperature industrial environment.

II. Functional Features and Design Advantages

1. **Thermal Magnetic Tripping System**

   - **Overload Protection**: The long-time delay tripping is achieved through the thermal effect of the bimetallic strip, with a setting range of **0.7-1×In**.

   - **Short-circuit Protection**: The electromagnetic trip acts instantaneously, with a response time of less than **0.1 seconds**.

   - **No-power Consumption Design**: No external power supply is required, with high reliability, suitable for harsh environments.

2. **Modular Design**

   - **Accessory Expansion**: Supports accessories such as **shunt trip (MX)**, **auxiliary contact (OF)**, **alarm contact (SD)**, etc., to achieve functions such as remote control, signal feedback, or fault alarm.

   - **Tool-free Installation**: Installed on a **TH35-7.5mm rail**, supporting quick disassembly and maintenance.

3. **Safety and Certification**

   - **Complete Certifications**: Complies with **CCC, CE, RoHS** certifications, and some models have passed **TUV, SAA** certifications.

   - **Arc Extinguishing Technology**: It has a built-in **fast arc extinguishing chamber**, and the arcing distance is zero, so it can be directly installed near the door panel of the control cabinet.

 III. Application Scenarios

1. **Residential and Building**

   - **Main Switch of Distribution Box**: Controls the total incoming power supply and protects the household circuit from overload and short-circuit effects.

   - **Lighting and Socket Circuits**: **Type C tripping** is suitable for mixed loads such as LED lights and household appliances.

   - **Coal-to-Electricity Projects**: **Type D tripping** supports the high starting current of electric heating equipment.

2. **Industrial and Commercial**

   - **Equipment Control**: **3P or 4P circuit breakers** are used for the short-circuit protection of small motors and frequency converters.

   - **Photovoltaic Inverters**: **DC circuit breakers** control the charging and discharging of the energy storage system (customization required).

   - **Temporary Power Supply**: **1P+N models** support the flexible configuration of portable distribution boxes.

3. **New Energy Field**

   - **Charging Pile Protection**: **Type D tripping** can deal with the instantaneous current impact during charging.

   - **Energy Storage System**: **Models with high interrupting capacity** (such as NXB-63H) ensure the safe switching of the busbar.

 IV. Market Information and Purchase Suggestions

1. **Supply and Price**

   - **Supply Status**: There is still a stable inventory in 2025, and it can be purchased through **Chint Mall**, **Alibaba**, or local distributors.

   - **Price Range**:

     - **1P C16**: Approximately **12-15 yuan per piece**.

     - **4P D63**: Approximately **70-80 yuan per piece**.

   - **Bulk Purchase**: A **30%-50%** discount can be enjoyed when purchasing a full box (such as 90 pieces per box).

2. **Alternative Models**

   - **High Interrupting Capacity Requirements**: **NXB-63H** (10kA) replaces the ordinary NXB-63 (6kA).

   - **DC Applications**: **NXB-63DC** (customization required) is suitable for 24V/48V DC systems.

   - **Intelligent Control**: **NXB-63G** supports the Internet of Things module to achieve remote monitoring.

3. **Purchase Precautions**

   - **Current Matching**: Select the **rated current** according to the load power (for example, select C16 for a 3kW motor).

   - **Certification Requirements**: Confirm the **CE certification** when exporting to Europe and the **SAA certification** when exporting to Australia.

   - **Accessory Compatibility**: The shunt trip (MX) needs to match the **220V or 380V coil voltage**.

 V. Installation and Maintenance Guide

1. **Installation Steps**

   - **Rail Installation**: Directly snap into the **TH35-7.5mm standard rail** without tools.

   - **Wiring Requirements**:

     - **Copper Wire**: The recommended cross-sectional area is **1.5-10mm²**, and the stripping length is **10-16mm**.

     - **Torque Control**: The tightening torque of the wiring terminal is **2.0N·m**, and the maximum should not exceed **2.5N·m**.

2. **Maintenance Suggestions**

   - **Regular Inspection**: Clean the contacts quarterly and check whether the wiring is loose.

   - **Fault Handling**: After the short-circuit tripping, the fault needs to be **eliminated and manually reset**, and avoid direct

   - **Life Management**: It is recommended to replace the whole unit after the electrical life expires (20,000 times).

VI. Technical Documents and Support

- **Official Resources**:

  - Visit the [Chint Official Website](https://www.chint.net) to download the **NXB-63 Selection Manual** and **Installation Guide**.

  - Contact local authorized distributors (such as the [hebei china electric Store]to obtain customized technical support.

 Summary

The NXB-63 series has become the mainstream choice in the low-voltage power distribution field due to its high cost-effectiveness, modular design, and wide applicability. Its characteristics of **thermal magnetic tripping**, **fast arc extinguishing**, and **wide-temperature operation** can meet the diversified needs of residential, industrial, and new energy scenarios. When purchasing, pay attention to the current matching and certification requirements. If higher performance or intelligent functions are required, you can refer to the NXB-63H or NXB-63G series.