A circuit breaker is a switching device capable of closing, carrying, and interrupting current under normal circuit conditions and closing, carrying, and interrupting current under abnormal circuit conditions within a specified time. Circuit breakers are classified into high-voltage circuit breakers and low-voltage circuit breakers according to their application range. The boundary between high and low voltage is somewhat blurred; generally, those above 3kV are considered high-voltage electrical appliances. Circuit breakers can be used to distribute electrical energy, infrequently start asynchronous motors, and protect power lines and motors. When serious overloads, short circuits, or undervoltage faults occur, they can automatically disconnect the circuit. Their function is equivalent to a combination of a fuse switch and over/under-temperature relays. Moreover, generally, no parts need to be replaced after interrupting a fault current. They have gained widespread application. In the generation, transmission, and use of electricity, power distribution is an extremely important link. The power distribution system includes transformers and various high and low voltage electrical equipment, and low-voltage circuit breakers are a widely used type of electrical appliance.
Circuit breaker model and specifications
1. Classified by rated current: 1, 2, 3, 4, 5, 6, 10, 16, 16, 20, 25, 32, 40, 50, 60, 63, 100 (A).
2. Classified by the number of poles: single-pole, dual-pole, triple-pole, quadruple-pole;
3. According to the tripping method: Type C (5ln~10ln), Type D (10ln~16ln)
Each company's model number is different; generally, you can just say the number of poles and the number of amperes.
Common and high-quality miniature circuit breakers include the C65, C120, EA9, and INT125 series.
The parameter differences are as follows:
1. N---Breaking capacity, N is 6000A, H is 10000A, L is 15kA.
2. C---Trip curve, B is electronic protection, C is power distribution protection, and D is power protection.
3. 20A---Rated current, available in 1, 2, 4, 6, 10, 16, 20, 25, 32, 40, 50, and 63A.
4. 2P --- Number of poles, including 1, 2, 3, and 4 poles.
A residual current circuit breaker (RCCB) is a switch that automatically trips when the leakage current in a circuit exceeds a predetermined value. Common RCCBs are classified into two types: voltage-type and current-type. Current-type RCCBs are further divided into electromagnetic and electronic types. RCCBs are used to prevent electric shock and should be selected based on the different requirements for protection against direct and indirect contact electric shock.
