Circuit breaker operation
Regardless of which class the circuit breaker belongs to, its main task is to operate in the event of an excessive current in the network, and before damage to the protective equipment and cable occurs,

the circuit breaker must de-energize the network.

There are 2 types of dangerous currents in the network:

Overcurrents caused by short circuit. The cause of a short circuit is the short circuit of the neutral and phase conductors between themselves.

In the normal state, the phase and neutral wires are connected to the load separately from each other.

overload currents. The appearance of such currents often occurs if the total power of the connected devices to the line exceeds the maximum allowable rate.

Class B protective devices
All devices of category B have a lower sensitivity, in comparison with devices of category A. The operation of the electromagnetic release in them occurs when the nominal value of the machine is exceeded by 200%. In this case, the response time of these devices is 0.015 sec.

Category B devices are used for installation in lines that include lighting devices, sockets and also in other circuits in which there are no starting currents or they have a minimum value.

Category C devices
Type C devices are very common in household networks. The overload resistance of these devices is higher than that of all of the above. In order for the electromagnetic release solenoid to operate, the current passing through the release must exceed 5 times the nominal value. The thermal release trips if the nominal value is exceeded by 5 times after 1.5 seconds.

As mentioned earlier, switches with a time-current characteristic C are usually installed in domestic networks. These devices work great as introductory devices to protect the overall network.