Detailed Explanation of Power Breaker Switch
I. Core Functions and Types
1. **Basic Functions**
- **Overload Protection**: Automatically disconnects when the current exceeds the rated value.
- **Short Circuit Protection**: Quickly cuts off the circuit when there is a large instantaneous current (the response time is usually ≤ 0.1 seconds).
- **Under-Voltage/Over-Voltage Protection** (for some high-end models): Trips when the voltage is abnormal.
2. **Common Types**
- **Miniature Circuit Breaker (MCB)**:
- Current range: 1A - 125A, used for residential or small commercial power distribution.
- Breaking capacity: 6kA - 15kA (commonly 6kA/10kA for household use).
- **Molded Case Circuit Breaker (MCCB)**:
- Current range: 100A - 1600A, suitable for industrial or large building applications.
- Breaking capacity: 15kA - 150kA (industrial grade can reach over 100kA).
- **Residual Current Device (RCD)**:
- With an additional leakage protection function, the operating current is 30mA (for household use) or above 100mA (for industrial use).
II. Key Parameters for Model Selection
1. **Rated Current (In)**
- Calculation formula:
- **Example**: For a household with a total power of 10kW (220V, power factor of 0.8), the calculated current is approximately 56.8A, and a 63A circuit breaker can be selected.
2. **Breaking Capacity (Icu/Ics)**
- **Icu**: Ultimate breaking capacity (the maximum one-time short-circuit current).
- **Ics**: Service breaking capacity (the current that can be broken repeatedly).
- **Selection principle**: Icu ≥ Expected short-circuit current at the installation point (data can be obtained from the power supply company).
3. **Number of Poles (Pole)**
- **1P**: Single pole (only disconnects the live wire, used for lighting circuits).
- **2P**: Double pole (disconnects the live wire + neutral wire, used for sockets or the main switch).
- **3P/4P**: Three-phase circuit breakers (for industrial equipment or three-phase power supply systems).
III. Comparison between Residential and Industrial Applications
| Parameter Items | Residential Scenario (MCB) | Industrial Scenario (MCCB) |
| Typical Current | 16A - 63A | 100A - 1600A |
| Breaking Capacity | 6kA - 10kA | 15kA - 150kA |
| Protection Functions | Overload + Short Circuit + Leakage (RCD optional) | Overload + Short Circuit + Ground Fault + Under-Voltage |
| Installation Method | Rail-mounted (35mm standard) | Drawer type or fixed type |
| Accessory Expansion | Optional auxiliary contacts, alarm modules | Supports electric operation, communication modules (Modbus) |
IV. Key Points of Installation and Maintenance
1. **Installation Steps**
- **Power-off Operation**: First disconnect the upper-level power supply and carry out construction after verifying that there is no electricity.
- **Wiring Specifications**:
- Connect the live wire to the upper terminal of the circuit breaker, and connect the neutral wire to the neutral busbar (do not connect it to the circuit breaker).
- The ground wire needs to be directly connected to the grounding terminal of the box.
- **Fixing Requirements**: Use screws to fasten tightly to avoid excessive contact resistance caused by looseness.
YouTube：https://youtube.com/shorts/dzB4hVFjRnI
2. **Troubleshooting of Common Problems**
- **Frequent Tripping**:
- Reasons: Excessive load, line short circuit, leakage, aging of the circuit breaker.
- Solutions: Check the load distribution and measure the insulation resistance with a multimeter (≥ 0.5MΩ).
- **Contact Ablation**:
- Phenomenon: Blackened contacts and poor contact.
- Treatment: Polish with fine sandpaper or replace the circuit breaker.
3. **Maintenance Cycle**
- Residential: Check the wiring terminals once every 2 to 3 years.
- Industrial: Conduct a comprehensive overhaul every year, and test the breaking time and operating characteristics.
V. Brand Recommendations
1. **High-end for Household Use**:
- Schneider C65 series, ABB T2/T3 series.
2. **Economical for Household Use**:
- CHNT DZ47 series, DELIXI CDB6 series.
3. **Industrial Grade**:
- Siemens 3VL series, Eaton 9E series.
VI. Precautions
1. **Coordination between Upper and Lower Levels**
- The breaking capacity of the upper-level circuit breaker needs to be greater than that of the lower-level one to avoid越级跳闸 (越级 tripping).
2. **Environmental Requirements**
- Installation environment temperature: -5°C to +40°C (derating is required if exceeded).
- Humidity: ≤ 90%RH (without condensation).
3. **Compliance Standards**
- Comply with GB 10963 (for household use) or GB 14048.2 (for industrial use).
If you need further assistance, please provide the following information:
1. Application scenario (residential/industrial/commercial).
2. Load power and voltage level.
3. Whether leakage protection or intelligent monitoring functions are required.
I will recommend specific models or provide troubleshooting solutions for you.
