Circuit Breakers
1. Circuit Breakers Overview
Circuit Breakers are core electronic components used for circuit protection. Their core functions include:
Overload Protection: Automatically cut off the power supply when the circuit current exceeds the rated value to prevent overheating or damage to the equipment.
Short Circuit Protection: Quickly disconnect the circuit when a short circuit fault occurs to prevent arc or fire risks.
Leakage Protection (some models): Detect leakage current and cut off the circuit to ensure personal safety (such as residual current operated circuit breakers).
2. What are the Typical Types of Circuit Breakers?
According to the structure and application scenarios, it is mainly divided into the following categories:
Air Circuit Breaker (MCB/MCCB): uses air as the arc extinguishing medium, commonly used in low-voltage distribution systems, such as household air switches (DZ47 series).
Residual Current Circuit Breaker (RCBO): Integrated overload, short circuit, and leakage protection functions, used in home and industrial power distribution systems (such as Chint DZ47LE-63 series).
Special Power Relay Circuit Breaker: Suitable for high current scenarios (such as 300A), with waterproof and moisture-proof characteristics, commonly used in engineering machinery and special vehicles (such as E-T-A MPR20 series).
3. What are the Key Parameters of Circuit Breakers?
1) Rated Current (In): Maximum current value for the continuous load (such as C10 means 10A), which needs to be selected according to the load current.
2) Breaking Capacity: Maximum fault current that the circuit breaker can safely cut off (such as 6000A).
3) Tripping Characteristics:
Type C: Suitable for conventional loads (such as lighting and household appliances), the instantaneous tripping current is 5-10 times the rated value.
Type D: For devices with large starting currents such as motors, with instantaneous tripping currents of 10-20 times the rated value.
4. What are the Typical Application Scenarios of Circuit Breakers?
Home and Commercial Buildings: Protect lighting and socket circuits to prevent overload or leakage accidents.
Industrial Equipment: Control high-power equipment such as motors and transformers, and support frequent operations.
Special Vehicles and Outdoor Equipment: Waterproof and corrosion-resistant design is suitable for harsh environments such as construction machinery and agricultural vehicles.
5. Using Precautions for Circuit Breakers
Matching Wire Specifications: The rated current of the circuit breaker should be less than the safe current carrying capacity of the wire to avoid overheating of the wire.
Regular Functional Testing: The leakage protector needs to verify the tripping reliability through the test button.
Distinguishing Between Fuses: Fuses are one-time protection devices, while circuit breakers can be manually reset and reused.
6. Related Standards and Certifications of Circuit Breakers
International Standards: such as IEC 60898-1 (household circuit breakers) and IEC 61009-1 (residual current protectors).
Certification Marks: CCC (China Compulsory Certification), EAC (Eurasian Economic Union Certification), etc.