- Batch switch
- Residual current device (RCD)
- Circuit breaker, also known as a bag.
- Differential automatic machine (bagger)
One of the most important electrical devices are circuit breakers. Pouches or circuit breakers are needed to protect the electrical system of the entire apartment or house from potential surges and surges. There are several types of burst switches.
Directly a packet switch is called such a device, shown in the photo above. As you can see, this is a rather outdated version, which was installed on stairwells in Soviet times. It is impossible to disconnect such a packet switch from the network, but it ensures that the current supply to the apartment is cut off..
The design of this type of circuit-breaker leads to the fact that it is damaged even in the case of a small current load. It turns out that the packet switch becomes the most vulnerable link in the power grid, in addition, it has a fairly low bandwidth and does not meet modern power consumption requirements.
Today, packet switches are everywhere giving way to automatic machines, but they are still found in old houses in stairwells. According to the degree of protection, packet switches can be open, closed and sealed.
Residual current device (RCD)
A more modern version of the device, which allows you to protect the apartment from current leaks. The RCD is triggered if a leakage current appears in the power grid, that is, a differential current. The appearance of such a current can lead to human injury, as well as heating of the electrical wiring, which causes a fire and fire..
Thus, an RCD is installed in order to obtain protection against electric shock and fire. Quite simply, a residual current device is an indicator that monitors the leakage of current that can begin to flow past consumers such as light bulbs and other electrical appliances. The RCD immediately reacts by disconnecting the network to insulation damage and the appearance of a leakage current.
However, the residual current device cannot protect against overload. For example, if all powerful electrical appliances are turned on in the apartment at the same time, then the RCD will not work. The device is also unable to protect against a short circuit. That is why the RCD is always connected in series with the machine.
Circuit breaker, also known as a bag.
It is with him that the RCD described above is connected in series. This is a switching contact device that is capable of conducting currents, turning them on and off in the event of a short circuit and other abnormal conditions in the network. Convenient in that it can be used repeatedly, protecting the apartment from short circuits.
By type, the bags are divided:
- for one-, two-, three- and four-pole;
- air circuit breakers, molded case devices, modular;
- by the nature of the current in the main network;
- current-limiting and non-current limiting;
- by type of release;
- selective and non-selective (according to the type of cutoff design);
- with manual, spring and motor drive;
- with and without contacts;
- with and without time delay. The time delay can also depend on the current or not;
- withdrawable, with plug-in contacts, and stationary;
- on the presence of protection from the environment, as well as contact with parts of the switch that are energized, and its degree;
- with front, rear, universal and combined connection of external conductors.
There are GOSTs 9098–78 and 14255, which establish the classification of machines and requirements for their protection..
Differential automatic machine (bagger)
An electric combined low-voltage device that conveniently combines the functions of a conventional circuit breaker and an RCD. That is, it is a modified, more modern version of the bagger. The differential automatic machine is quite popular, it is used both at production facilities and in everyday life. Protects the apartment from short circuits, current leaks, and the owners from electrical damage.
Main structural elements:
- differential transformer;
- thermal release;
- electromagnetic release.
The amount of differential transformer winding will depend on the number of poles of the device. A thermal release is needed to protect against overloads, and the electromagnet of the electromagnetic release is triggered in the event of a short circuit.
The advantages of the difavtomat, which will immediately replace both the RCD and the circuit breaker, include its compactness. According to the characteristics of these two devices, the difavtomat is in no way inferior.
Electromagnetic two-position device, which is designed for frequent remote switching off and on of electrical circuits. Moreover, the shutdown occurs during normal operation. In general, a contactor is a kind of electromagnetic relay. Three-pole AC contactors are widely used, as well as single and two-pole DC devices..
Contactors have special requirements in terms of electrical and mechanical durability, because the on and off cycles can be repeated from 30 and 3.6 thousand times (depending on the category). The main difference between contactors and circuit breakers is that they switch only rated currents; in the event of a short circuit, the device does not work. The contactor includes:
- contact system;
- electromagnetic system;
- block contacts system;
- arc suppression system.
As a rule, contactors are used for the purpose of switching industrial current circuits, including in the control of powerful electric motors, in trolleybus and tram cars, on elevators, in electric and diesel locomotives, electric trains.
To summarize – today in everyday life, either differential automatic machines or RCDs are usually used together with circuit breakers (packers). Traditionally, these devices, necessary in every house, are installed at the place where electrical wiring is entered into an apartment or house, next to the meter. Sachets and difavtomats allow you to turn off the power supply to the house, if necessary for carrying out any work in the electrical system. But their main purpose is to protect household electrical appliances from voltage surges, overloads, short circuits..