Electricity is a very useful and at the same time dangerous invention. In addition to the direct impact of current on a person, there is also a high probability of fire if the electrical wiring is not connected. This is explained by the fact that the electric current passing through the conductor heats it up, and especially high temperatures occur in places with poor contact or in the event of a short circuit. To prevent such situations, machines are used.
What are circuit breakers?
These are specially designed devices, the main task of which is to protect the wiring from melting. In general, machines will not save you from electric shock and will not protect equipment. They are designed to prevent overheating.
The method of their work is based on opening the electrical circuit in several cases:
- short circuit;
- exceeding the current flowing through the conductor for this is not intended.
As a rule, the machine is installed at the input, that is, it protects the section of the circuit following it. Since different wiring is used for breeding different types of devices, it means that protection devices must be able to operate at different currents.
On the surface, it may seem that it is enough to install simplythe most powerful machine and no problems. However, it is not. A high current that has not been triggered by a protection device can overheat the wiring and, as a result, cause a fire.
Installation of low power circuit breakers will break the circuit every time as soon as two or more powerful consumers are connected to the network.
What does the machine consist of?
A regular automaton consists of the following elements:
- Cocking handle. With it, you can turn on the machine after it has been triggered, or turn it off to de-energize the circuit.
- Activation mechanism.
- Contacts. Provides connection and break of the chain.
- Terminals. Connect to a protected network.
- Mechanism triggered by condition. For example, a bimetallic thermal plate.
- Many models may have an adjusting screw to adjust the current rating.
- The arc-extinguishing mechanism. Present at each of the poles of the device. It is a small chamber in which copper-plated plates are placed. On them, the arc is extinguished and disappears.
Depending on the manufacturer, model and purpose, machines can be equipped with additional mechanisms and devices.
Disconnect mechanism device
The machines have an element that breaks the electrical circuit at critical current values. Their working principle can be based on different technologies:
- Electromagnetic devices. Differ in the high speed of reaction to short circuit. Under the action of currents of an unacceptable value, a coil with a core is activated, which, in turn, disconnects the circuit.
- Thermal. The main element of such a mechanism is a bimetallic plate, which begins to deform under the load of high currents. Bending, it has a physical effect on the element that breaks the chain. Approximately according to the same scheme, an electric kettle works, which is able to turn itself off when water boils in it.
- There are also semiconductor open circuit systems. But they are rarely used in household networks.
Types of automata by current values
Devices differ in the nature of the response to an excessively high current value. There are 3 most popular types of automata - B, C, D. Each letter means the sensitivity factor of the device. For example, an automaton of type D has a value between 10 and 20 xln. What does it mean? It's very simple - to understand the range at which the machine is able to work, you need to multiply the number next to the letter by the value. That is, a device marked D30 will turn off at 3010 … 3020 or from 300 A to 600 A. But such machines are used mainly in places with consumers that have large starting currents, for example, electric motors.
Automaton type B has a value between 3 and 5 xln. Therefore, marking B16 means operation at currents from 48 to 80A.
But the most common type of machines is C. It is used in almost every home. Hischaracteristics - from 5 to 10 xln.
Symbols
Different types of machines are marked in their own way for quick identification and selection of the right one for a particular circuit or its section. As a rule, all manufacturers adhere to one mechanism that allows unifying products for many industries and regions. Let's analyze in more detail the signs and numbers applied to the machine:
- Brand. Usually, the manufacturer's logo is placed at the top of the machine. Almost all of them are stylized in a certain way and have their own corporate color, so it will not be difficult to choose a product of your favorite company.
- Indicator window. Shows the current status of the contacts. If a malfunction occurs in the machine, then it can be used to determine whether there is voltage in the network.
- Type of machine. As already described above, it means the tripping characteristic at currents that are much higher than the rated current. C is used more often in everyday life and B a little less often. The differences between the types of electric machines B and C are not so significant;
- Rated current. Shows the current value that can withstand continuous load.
- Rated voltage. Very often, this indicator has two values, written with a slash. The first is for a single-phase network, the second is for a three-phase network. As a rule, 220 V is used in Russia.
- Cut-off current limit. Means the maximum allowable short circuit current at which the machine will turn off without failure.
- Current limiting class. Expressed in one digitor is absent altogether. In the latter case, it is customary to consider the class number 1. This characteristic means the time for which the short-circuit current is limited.
- Scheme. On the machine, you can even find a connection diagram for contacts with their designations. It is almost always located in the upper right side.
Thus, looking at the front of the machine, you can immediately determine what type of current it is intended for and what it is capable of.
Which type of machine to choose?
When choosing a protective device, one of the main characteristics is considered to be the rated current. To do this, you need to determine what current strength is required by the totality of all consumer devices in the house.
And since electricity flows through wires, the current required for heating depends on its cross section.
The presence of poles also plays an important role. The most common practice is:
- One pole. Circuits with lights and sockets to which simple appliances will be connected.
- Two poles. It is used to protect wiring to electric stoves, washing machines, heaters, water heaters. It can also be installed as a protection between the shield and the room.
- Three poles. It is mainly used in three-phase circuits. This is true for industrial or near-industrial premises. Small workshops, factories and the like.
Tactics of installing automatic machines goes from largest to smallest. That is, first mounted,for example, bipolar, then unipolar. Next come devices with power decreasing with each step.
Some tips for choosing a machine
- When choosing, you should focus not on electrical appliances, but on wiring, since it will be protected by circuit breakers. If it is old, it is recommended to replace it so that you can use the most optimal version of the machine.
- For premises such as a garage, or for the time of repair work, it is worth choosing an automatic machine with a larger rated current, since various machines or welding machines have rather large current strengths.
- It makes sense to complete the entire set of protective mechanisms from the same manufacturer. This will help avoid current rating mismatches between appliances.
- It is better to buy vending machines in specialized stores. This way you can avoid buying a low-quality fake, which can lead to disastrous consequences.
Conclusion
No matter how simple the wiring of the chain around the room may seem, you should always remember about safety. The use of automatic machines greatly helps to avoid overheating and, as a result, its ignition.
