What is three-phase electricity. What is better for a private home - single-phase or three-phase input

If you plan to connect a private house to electrical networks, then the question arises of which input to the house to choose. In this article we will consider what is better for a private home - single-phase or three-phase input. If we compare the load of modern household electrical appliances with the load of electrical appliances from twenty years ago, we can conclude that the amount of electricity consumed today has increased several times. Moreover, there is a trend of constant increase in consumed electrical energy per capita. This is due, first of all, to the fact that in every home a huge number of household electrical appliances have appeared, characterized by high power and, accordingly, a large amount of electrical energy consumed. If previously the load limit for the electrical wiring of one apartment (house) was 8-10 A, now such a limit is enough for one electric kettle, the load of which is 10 A. What is the difference between a single-phase electrical input and a three-phase one? Almost all household electrical appliances are designed to work in single-phase network alternating current. That is, to connect a household electrical appliance you need one phase and a neutral conductor. Single-phase input - one phase and a neutral conductor, three-phase input - three phases and a neutral conductor, respectively. Based on this, we can conclude that the fundamental difference between a three-phase input and a single-phase input is the number of phases.

Reason for which three phase electricity mainly used in industry, is to permit the use of one, specific, essential part electric machines- ubiquitous three-phase asynchronous motor. All electrical energy coming from generator sets utilities through transmission and distribution systems, represents three phase power, coming from these three-phase induction generators. Of course, this is done using three-phase transformers. people seem to forget when discussing three phase electricity, is that there is a difference between "lines" and "phases".

Advantages of three-phase input in a private house

The advantages of three-phase input in a private house are obvious. You can use one phase to power the electrical wiring at home, the second phase to power the most powerful household appliances home, for example a kitchen, and a third for power supply to the garage and other auxiliary premises on the territory of a private house. In addition, you have another advantage - the ability to connect three-phase electrical energy consumers, which is especially important for a private home. For example, three-phase welding machine, electric stove, heater, water pump, as well as other devices with asynchronous three-phase motors(grain threshers, compressors, etc.). The main advantage of using three-phase electrical appliances is the absence of phase imbalance in electrical network, since the load of these electrical appliances is evenly distributed over three phases of the electrical network. It should be noted that when using a three-phase input, the question arises about uniform distribution of the load of single-phase household electrical appliances in a private home. Otherwise, that is, with significant load asymmetry, phase imbalance is possible, in particular, phase imbalance phase voltages. Therefore, when designing three-phase electrical wiring for a private house, it is necessary to correctly distribute the load of household single-phase electrical appliances. In addition to the above, one more thing should be highlighted characteristic feature three-phase input to a private house - significantly larger size metering and distribution electrical panel compared to a single-phase panel. This is primarily due to the fact that a three-phase meter is much larger than a single-phase one. As for modular protective devices, for three-phase circuit breakers, devices protective shutdown Significantly more modular spaces are needed in the electrical distribution panel. In addition, the electrical wiring diagram of a private house with a three-phase input is characterized by a larger number of lines and, accordingly, protective devices, compared to single-phase wiring, for which it is also necessary to provide a place in the apartment panel. Problem big size three-phase metering and distribution panel of a private house can be solved. It is not necessary to install the shield inside the house; it can be installed outside. If you decide to install a distribution panel on the street, then pay Special attention on the degree of protection of the housing IP. As a rule, the degree of protection of the shield housing intended for outdoor installation is IP31 or IP54. To ensure ease of maintenance of the electrical wiring of a private house, it is possible to install several distribution panels. For example, on the street you can install a panel of type SHRUN -3/12, in which an electrical energy meter, as well as incoming protection devices, will be located. A small plastic box Tuso 68112 SP 12, designed for 12 modular places, will be installed in the house, in which devices for protecting the electrical wiring lines of the house will be located. Another similar shield can be installed in a garage or other structure on the territory of a private house. In general, you can design the electrical wiring diagram of a private house in accordance with your needs and the convenience of further maintenance. As for power consumption limits, in this case there is a misconception that three-phase input is a significantly higher power consumption limit. In this case, everything depends on the established standards of the energy supply company, which connects private houses to electrical networks. In accordance with current technical specifications connecting private houses, the same power consumption limit can be set for both single-phase and three-phase input. Which input should I choose, single-phase or three-phase? If the power consumption limit is the same for both single-phase and three-phase input, then you should be guided by the need to use three-phase household electrical appliances. If you do not have three-phase household electrical appliances in your household, and you do not plan to use them in the future, then it makes no sense to install a three-phase input into the house. In addition to the above, it should be noted that connecting a three-phase input is a rather painstaking process, which is somewhat more complicated than the procedure for connecting a single-phase input to an electrical network. This is primarily due to the fact that the use of three-phase input requires greater requirements for fire safety houses and other buildings on its territory.

Time and time again the question arises: what is better for a dacha and individual residential premises - three-phase or single-phase input? And what's so special about three-phase?
There are three wires that lead the output three-phase generator. The three lines coming out of the alternator end up at three terminals on the primary side of the transformer. A three-phase primary consists of three, distinct primary coils that are all tied together in a "Delta" configuration - the ends of the three coils are connected together in a daisy chain to form a conceptual triangle.

This is what is known as "bastard tension." For single-phase residential power, the secondary three-phase transformer is connected to the "Wye" configuration. In this case neutral wire comes from center point. Paying less for your electricity three-phase mode.
Let's figure it out.
First of all, all our networks coming from transformer substations, three-phase. They have four wires - three phase and neutral. If all three phases are supplied to the house, this is a three-phase input. If only one goes out, the input is single-phase.
Generally speaking, a three-phase connection has many advantages over a single-phase connection. This means greater transmitted power with the same wire cross-section, and more powerful, reliable and compact electrical consumers, and more uniform loading of networks and TP, and something else.
What is a three-phase meter?
An electricity meter is the equipment that provides communication between the electricity distribution network and your installation. It measures your home's electricity consumption: your meter indicates the number of kilowatts per hour, which depends on the power of your appliances and how long you use them. With a meter, your electricity supplier can set your bills.

Your meter can be located inside your home, on your deck, or even outside. However, whether your meter is at home or not is not yours: it is a property local to the electricity distribution system operator, and therefore a change of electricity supplier on your part does not result in any changes to the meter.
BUT! There is one very important thing But! To take advantage of a three-phase connection, consumers must also be three-phase, designed for such a connection. And now they are not in everyday life. Simply no...
Previously, in Soviet times, people en masse carried low-power asynchronous three-phase motors from work and used them to make all sorts of circular machines, lathes, drilling machines and much more. It was quite difficult to connect such devices in a regular single-phase network - maybe there was a genetic longing for three phases left over from that time?
Selection of meter power
Once the connection has been made, the consumer subscribes to: he determines the power of the installation to control several electrical appliances simultaneously. It is important to choose this power, signed carefully, in accordance with the real needs of the housing and its inhabitants. Indeed, the higher the power, the more the subscription price increases: the right balance must be found to avoid disjunctions and waste.

Three steps for installation
For getting additional information refer to the article dedicated. There are two main types of meters: single-phase and three-phase. In single-phase mode, electricity is supplied to one electrical circuit for the entire enclosure: all electrical equipment will be connected to this single phase.
Because when connecting single-phase equipment to a technical phase network, one difficulty arises.
Complexity related to power.
And it consists in the following.
Let's say you are allocated 10 kW of three-phase power,
To limit it, you will have a 16A machine at the input.
But don't think that you can plug in any single-phase device with a power of 10 kW - you can only use 3.5 kW in one phase. That is, you cannot use anything more powerful than this value. Moreover, if you use equipment with current surges in starting modes, such as all kinds of electric motors, transformers, etc., then this figure can be safely reduced by another one and a half to two times.
In what cases is a three-phase meter used?
But in some cases it is necessary to install three separate circuits, each of which will serve part of the house. Each circuit is connected to a phase of the same power: this is called a three-phase installation. As a rule, for private households, a single-phase meter predominates. However, three reasons may prompt a consumer to choose a three-phase installation.

Disadvantages of three-phase current subscription
Firstly, this is the high power consumption of the case. . For three-phase installation requires systematic and uniform distribution electrical consumption between each phase, otherwise the installation may be shut down, since the imbalance can lead to significant electricity consumption on one phase, it may incur.
Moreover, when installing electrical networks with your own hands, a common mistake is when all the sockets are placed on one phase, lighting on another, and some kind of power supply on the third. technological equipment type of pumps. As a result, one phase is overloaded in advance, and since single phase power it is almost three times less than three-phase... And since at least some selectivity must be ensured, and therefore, willy-nilly, you have to put the machine on the sockets one step lower than on the input...
The machine guns begin to break out.
Now, this is the main problem.
However, if all Appliances enclosure is connected to one phase, this limit can easily be exceeded. All electrical system will turn off even if general power the counter will not be reached. Do you have doubts about your subscription and your actual consumption?

To reduce the power subscribed to your installation in three-phase mode and thus reduce your electricity bill, you may want to consider switching to a single-phase meter. First, make sure that your equipment does not require a three-phase connection. If this is the case, you can call an electrician who can make the necessary changes to your installation. Allow between 150 and 300 euros for this service, as well as an average delay of three weeks between the request and the passage of the technique.
For electricians, three-phase connection of consumers is beneficial. For us it's the opposite. And if it’s allowed at all low power, type 6 kW. or less, then 3 phases turn into a disaster. The machines can be knocked out from a regular iron or electric kettle...