Generally, the most common distribution box includes circuit breaker, leakage circuit breaker and overvoltage and undervoltage protector. Together, they play a role in protecting power safety. There are also differences between them. What are the specific differences?

1. Circuit breaker

Circuit breaker, also known as air circuit breaker, is a kind of circuit breaker. It is a switch that will automatically disconnect when the current in the circuit exceeds the rated current. In addition to different circuits in the home, such as lighting and toilet power circuits, which can be controlled by circuit breakers, it can also protect the short circuit and serious overload of circuits or electrical equipment. At the same time, it can also be used to start the motor infrequently.

2. Leakage circuit breaker

Leakage circuit breaker refers to the switch that can automatically act when the leakage current in the circuit exceeds the predetermined value, also known as leakage protector, referred to as leakage switch for short.

The commonly used leakage circuit breakers are divided into voltage type and current type, and the current type can be divided into electromagnetic type and electronic type. Leakage circuit breaker is used to prevent personal electric shock, which shall be selected according to the different requirements of direct contact and indirect contact.

3. Overvoltage and undervoltage protector

Overpressure, overvoltage and undervoltage protectors are mainly used to intelligently, automatically and quickly cut off the power supply in case of sudden change of power grid voltage and overpressure, overvoltage and undervoltage.

4. Surge protector

Surge protector (SPD), also known as lightning arrester (SPD), protects the surge affected by indirect lightning and direct lightning or other instantaneous overvoltage.

Under normal conditions, the resistance of surge protector is infinite, which is equivalent to open circuit. When transient overvoltage or overcurrent occurs in the circuit, the surge protector will be turned on quickly, so as to lead the overvoltage or overcurrent to the earth.

Surge protective devices are divided into three levels according to the areas to be protected,

The first level surge protector can be applied to the general distribution cabinet in the building to discharge the direct lightning strike current, and the discharge current is 80kA ~ 200kA;

The second level surge protector is applied to the shunt distribution cabinet of the building. It is a protective equipment for the participating voltage of the previous level lightning arrester and induced lightning strike in the area, and the discharge current is about 40ka;

The third level surge protector is applied to the front end of important equipment and is a means to protect equipment. It protects LEMP and residual lightning energy passing through the second level anti lightning device, and the discharge current is about 20KA.

Differences among circuit breaker, leakage circuit breaker, overvoltage and undervoltage protector and surge protector

1. Function of leakage protector: to solve leakage problems, such as electric shock to human body, current flows to the ground through human body, generally more than 30 Ma, and the leakage protector will cut off the power supply, so as to avoid current damage to human body.

2. Function of circuit breaker: when the current passing through the switch exceeds a certain current, the switch will trip and cut off the power supply due to heating to the bending of metal sheet. The protection circuit will not be burned due to excessive current, but only play the role of protection circuit.

3. Overpressure, overvoltage and undervoltage Protector: its main function is to comprehensively monitor, control and protect the voltage.

4. Surge protector: mainly used for lightning protection and overvoltage protection.

Conclusion: leakage protector and circuit breaker only control the current, ignoring the control of voltage. Adding overvoltage and undervoltage protector and surge protector on the basis of leakage protector and circuit breaker can realize the protection of current and voltage, so as to avoid the damage to life and property due to the abnormal sudden rise of current and voltage.