What machines to put in an apartment or a private house?

Circuit breakers are switching equipment designed to protect electrical wiring from overloads. If the circuit is in normal condition, current is supplied to it from the common line through the machine. When the current value exceeds the critical parameters, the device is triggered and the line is de-energized. In this article, we will talk about which machines to install in a private house or apartment in order to ensure the serviceability of the wiring and protect yourself and your property from fire.

When choosing a circuit breaker, it should be borne in mind that the magnitude of the current that causes it to operate should be less than the permissible by about 10%. When calculating the expected loads, it is necessary to select the cross-section of the conductors based on the results obtained.

If it is planned to increase the load, it is necessary to install cables with a larger cross section, at the same time replacing the protective device with a more powerful one. If this is not done, old electrical wires will simply burn out from overload.

The device and principle of operation of AB

For a home network, the VA series switches are most often used. Their feature is the presence of two types of protection at once, namely, thermal and electromagnetic.

The bag consists of several parts, the main of which is a bimetallic plate that reacts to the amount of current that passes through it. When it exceeds the nominal value, the plate heats up, bends towards the shutdown and triggers the machine.

After normalization of the current value, it cools down, after which the protective device can be turned on again.

This is how thermal protection works.

The electromagnetic protection is triggered by short-circuit overcurrents. When they pass through the release, the movable core of the latter shifts to the side and triggers the shutdown mechanism, which opens the contacts and de-energizes the wiring.

The device and principle of operation of the circuit breaker in the video:

Opening the contacts causes a high power electric arc, which can lead to their destruction. To neutralize it, the device is equipped with an arc-extinguishing chamber, which includes parallel-mounted metal plates. Attracting to them, the arc is split into parts, cooled and extinguished.

If necessary, turning on and off the machines can be done manually. A serviceable automaton can withstand the flow of electrons passing through it for an unlimited time, if the value of the latter does not exceed the nominal value.

Varieties of circuit breakers

These devices are divided into several types, each of which has its own characteristics of operation and is intended for installation in various circuits:

• MA. Thermal release is not provided for these machines. When connected to a load (for example, an electric motor), the current relay only needs a switch that provides short-circuit protection.
• A. The thermal release in these devices is triggered when the electric current exceeds the rating by 30%. The electromagnetic release here causes a power failure in 0.05 s if the current exceeds the nominal value by 100%. If, for any reason, the coil did not work, then after about 25-30 s, thermal protection comes into play, causing the machine to trip. Type A protective devices should be installed in electrical circuits with semiconductor elements that can malfunction even with a slight increase in current.In order to protect electronic devices, automatic machines of the Z brand can be included in the circuit, which are triggered when the current doubles.

• B. In these devices, the thermal release operates within 4-5 s, and the electromagnetic protection acts for 0.015 s, if the current exceeds the nominal by 200%. Automatic machines of this type are widely used in lighting circuits, characterized by a small starting current.
• C. These machines are the most common. Both types of protection are tripped in it when the value of the rated current passing through the breaker is exceeded by 400%.

This device, which allows a moderate inrush current, is best placed in a household electrical panel.

• D and K. These devices are usually installed in industrial networks with high starting currents of equipment. However, a brand D machine can also be installed in a private house, in which an electric boiler or high-power electric motor is connected.

Having dealt with the types of devices, we turn to the question of their choice.

How to choose a circuit breaker?

The choice of circuit breakers is carried out according to a number of criteria:

• Rated current. When this parameter is exceeded, the circuit breaker trips, thereby protecting the circuit from damage due to overload. It should be chosen based on the cross-section of the cables that are connected to AB. The rated current for the protective device must be 85-90% of the value that the wiring can withstand.

• Selectivity. The current rating should be selected based on the load value of a particular line. The current value for main household appliances and elements is usually: 10 A for lighting fixtures, 16 A for electrical outlets, 25 A for high power electrical appliances, 32 A for an electric stove and 40 A for a main switch. These are general indicators and may vary. For example, if a 25 A device is connected through an electrical outlet, then it is selected for a similar current value.
• Tripping current. The nominal value of this parameter should be selected based on the load. The switching device for electronic devices must have a grade A or Z, a circuit breaker for a powerful electric motor with a high starting current - D, a protective device for an electric heating boiler - C, and for lighting devices - B. If the brands of automatic machines are selected correctly, then the equipment included into the circuit, will be reliably protected, and AB will not be triggered when, for example, a welding machine or a motor is turned on.
• Number of poles. To protect a single-phase household network to which high-power devices are not connected, a single or two-pole circuit breaker will be sufficient. If, for example, a heating boiler or an electric motor for three phases is included in the circuit, then AB must be three-pole.

• Manufacturers. Both in Russia and abroad, the production of automatic switches has been established, and in order to choose a high-quality automatic machine, you need to focus not only on the declared parameters. It is unlikely that it will be possible to buy good equipment on the market “out of the box”. Therefore, it is better to buy protective devices at specialized points where they are sold with accompanying documentation. Leading manufacturers value the brand of their company and a high rating, so you can not be afraid of running into a low quality product.

About the nuances of choosing a circuit breaker in the video:

Which company is the best switch to choose?

As we have already said, you should not purchase cheap protective devices from an unknown manufacturer, since the safety of people and property directly depends on the quality of these devices.

To protect yourself from the troubles associated with poor line protection, just buy a high-quality machine, which, by the way, does not cost much more than a fake.

If we talk about specific companies, we can advise devices from Schneider Electric, ABB and Legrand, which, with a nominal 16 A, currently cost from 120 to 230 rubles. There are also simpler and more budgetary options of a similar denomination, the price of which today does not exceed 50 rubles - EKF and IEK.

All AB provide for a certain number of operations. It is undesirable to use protective devices as load break switches - this leads to wear of the mechanism and burning of the contacts. In accordance with the requirements of the PUE, the load must be switched by means of relays or contactors.

It is very important not to be mistaken when determining the required number of protective devices. As a rule, an introductory machine is installed first. Other pouches protect lighting lines, sockets, as well as powerful electrical appliances that do not have built-in protection.

At AV manufactured by different companies, cables are connected and fastened in different ways. Therefore, if it is necessary to replace the machines in the dashboard, it is better to install similar products instead.

Review of Hager circuit breakers in the following video:

Conclusion

Summing up, let's say that modern circuit breakers protect the electrical network and devices connected to it both from short circuits and from prolonged overloads. In the first case, the thermal release is triggered, and in the second, the electromagnetic protection.

We also recall that you need to use AB for their intended purpose, and do not use electrical appliance switches as them, otherwise they will quickly fail. After reading this material, you learned which machines should be installed in an apartment or in a private house.