Scheme of connecting a house to a three-phase network

We assemble an electrical panel for a private house at 380 V 15 kW

Assembling an electrical panel for a private home with a voltage of 380 V and a power of up to 15 kW requires an appropriate approach and the presence of the following tools:

• pliers;
• flat and figured screwdrivers;
• crimping pliers;
• assembly knife with a set of replaceable blades.

All work begins with planning, and if the home owner prefers to contact an electrical company, then a project and preliminary diagram are drawn up before installation begins. You should also prepare the components of the shield and consumables (crimping lugs, heat shrink, DIN rail, dowels).

What elements does an electrical panel consist of?

It is necessary to purchase the components of the electrical panel immediately, so as not to subsequently waste time and not travel to the electrical store several times a day. The power of the shield is determined, it is 15 kW, which means that the maximum power consumption will not exceed 15 kW/h.

Electrical panel of a private house, list of elements:

1. Electric energy meter. The meter is the first element that must be installed in the panel. The best solution would be to purchase an electronic device designed to connect three phases. Such measuring instruments have high accuracy and a long service life. All information is displayed on a digital screen. Electronic meters can be programmed to operate in several tariffs.
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2. Electrical shield. Now in stores there are a large number of electrical panels of various sizes and designed for a certain number of elements. The price of the product varies depending on the presence of a DIN rail, a built-in lock, as well as an inspection window (especially for taking readings from the meter). You should pay attention to protection from dust and moisture, its level should be at least IP 54. Dimensions - 445 × 400 × 150, and a wall thickness of 1 mm.

3. Input circuit breaker. You should purchase a three-pole machine, because the voltage supplied to the house will be 380 V, which means the presence of three phases.

4. Residual current device (RCD). It is required to be installed, since it is a protective element when a dangerous potential appears on the body of an electrical device.

5. Circuit breakers. The amperage should be selected based on the consumer load, which will be discussed below.

6. Voltage relay. Protects household electrical appliances from power surges. Many users install a relay, but it is not a required element. Also now widely used is the surge protection device (SPD). For example, when lightning strikes an overhead power line, the voltage in the house will reach high limits, which will be destructive for all equipment. The SPD will turn off the network in time, but, like the voltage relay, it is not installed often.

7. Measuring instruments. They are also an optional element of the electrical panel. Measuring instruments include ammeters and voltmeters, often combined into one product.

Load calculation by phases

Let's say you have a 1500 W three-phase motor. Accordingly, each phase accounts for 500 W of active power. Let's assume that cos phi=0.8. Total power is: 500/0.8. It turns out that 625 W needs to be distributed to each phase.

In addition to the motor, other consumers are probably connected to the phases. For example, in addition to 500 W, 200 W lighting and a 300 W convector are connected. All powers are summed horizontally. Reactive power remains unchanged (unless loads with a reactive component are used).

Using the Pythagorean theorem, reactive power can be determined.

But in practice these are quite complex calculations. Therefore, this is calculated approximately: 625 W + 500 W = 1150 W. This amount turns out to be more than the exact calculations according to the formula, but there is nothing terrible. The calculation was made with a small margin.

In practice, for approximate calculations it is enough to add up all the total capacities and from them determine the power of the machine for the required load.

Which circuit breakers to choose for the electrical panel

The main question that affects many users is: how to decide on slot machines? The rated current of the circuit breaker is calculated based on such parameters as the consumer’s load or its power.

For example. The rated power of simultaneously switched on electrical appliances and the lighting network will be 15 kW. There is a formula: P=U×I, where P is power, U is voltage, I is current. If P = 15000 W, then the current strength will be (rounded) 68 A. This means the sum of the rated values ​​of the machines should not exceed 68 A. But it should be remembered that a three-phase network is connected to the switchboard, so the rated amperes must be divided by 3, which will give approximately 23 A. This means that the input circuit breaker should be set to 25 A.

For lighting networks, it uses 6.3 or 10 A automatic machines. These are generally accepted standards, which are convenient to resort to to save time. If you still have free time, then you can calculate the amperage of the machine for light using the above formula, only P will be equal to the sum of the powers of all lamps used in a separate or common lighting line.

The amperage of automatic circuit breakers for power circuits should not be less than 16 A. It is this nominal value that will allow you to use electrical appliances uninterruptedly for a long time. If you install a circuit breaker with a lower rated threshold, then turning on the household appliance will be perceived by the device as a short circuit on the line and the circuit breaker will turn off the voltage.

There may also be more powerful electrical appliances in the house: hobs, ovens, refrigerators. And if several sockets can be combined into one group, then such devices will require the installation of a separate circuit breaker with a value of at least 25 A. The power of a modern electrical panel can reach 7 kW and higher.

Recommendations for choosing wires

In houses made of brick, aerated concrete blocks, and cinder blocks, interior wall decoration is required, which means that a hidden method is used for laying wires.

To provide additional protection, and in case of repair to quickly replace the cable, it is placed in a corrugated sleeve of non-flammable polymer.

In houses made of timber or rounded logs, to preserve the retro style, they use an open method of laying wires, purchasing decorative products - twisted wiring, rollers, stylized switches and sockets

To select the correct wire cross-section, specialists perform calculations related to determining the load.

However, based on standard diagrams and many years of experience, qualified electricians adhere to the following parameters:

• lighting circuits – 3*1.5 mm² or 3*2 mm²;
• socket groups – 3*2.5 mm²;
• electric stove/oven – 3*4 mm²;
• air conditioning – 3*2.5 mm², for appliances more powerful than 5 kW – 3*4 mm²;
• heating boilers – 3*4 mm² or more (according to the manufacturer’s recommendations).

The optimal type of cable is three-core copper: VVGng, ShVVPng. It is impossible to use wires with a cross-section smaller than the specified one, as they will not match the load and will begin to melt, creating a dangerous situation.

Sequence of correct installation of an electrical panel

To ensure that the electrical panel in your home is installed correctly, you should use only high-quality electrical products, as well as consumables. Only after installation is completed, operating voltage is supplied to the panel.

The correct assembly of a three-phase electrical panel has the following sequence:

1. Installation of an introductory machine. The device rating must cover the maximum power consumption. Since 3 phases will be brought into the house, the voltage between them will be 380 V, it is necessary to install a three-pole circuit breaker. To save money, it is not recommended to install 3 single-pole circuit breakers and connect them with a special strip. The input machine is installed in the upper left corner of the shield and is marked accordingly.
2. After the introductory machine, it is necessary to install an RCD. The rating of the device must correspond to the rating of the input switch. You should also pay attention to the cut-off current - the lower this indicator, the faster the RCD will turn off the network. There are differential circuit breakers that include protective functions against short circuits and shutdown the network when a leakage current occurs (RCD and standard switch). It is easier to use such a product, but its cost is quite high.
3. To the right of the RCD, at a short distance, a zero bus is mounted. Modern busbars provide a plastic dielectric between the copper strip and the shield body. This is done so that if the zero burns out and a phase gets on it, the electrical panel does not end up under life-threatening voltage.
4. Measuring instruments and voltage relays can also be placed on the strip with the input circuit breaker, RCD and zero bus. If you install a voltmeter and an ammeter in a three-phase network, then you must select products that display both linear and phase loads. And also capable of showing data on each phase separately.
5. The lower DIN rail contains automatic switches for power and lighting lines. In order not to get confused and not constantly look at the rating of the machines, lighting line products should be located at a short distance from the power switches.

Phase imbalance

In fact, distributing the load across phases in a private house, performed with phase imbalance, does not pose serious problems for equipment. But you are guaranteed to periodically turn off the circuit breaker.

Before distributing the load, it is necessary to understand the structure of the three-pole circuit breaker. Let's consider the situation using the example of the C 25 machine. It consists of 3 single-phase machines, each of which can withstand 25 A. Thus, each phase receives 5 kW of power, which means that connecting a cottage with a power of 15 kW. In this case, the machines can interrupt the power with one switch (lever).

An example of load distribution on a three-phase power supply for a cottage Source mastergrad.com

If you are considering the question of how to distribute the load across phases in a random (chaotic) order, pay attention to the following example:

• Phase No. 1 is connected to the lighting of the cottage.
• Phase No. 2 supplies power to the 1st floor outlets.
• Phase No. 3 powers the outlets on the 2nd floor.

As a result, the following will happen:

• On the 2nd floor there are several bedrooms and a bathroom. There are no powerful energy consumers here. As a result, Phase 3 will not operate at full capacity.
• A similar situation will occur with phase No. 1. Modern LED lighting consumes little electricity.
• The last phase No. 2 will be overloaded, due to the fact that the main, powerful consumers are “hung” on it: a washing machine, a microwave oven, a refrigerator and other equipment located in the premises of the first floor.

Important! As a result, the simultaneous inclusion of several elements of household appliances will overload the machine, which will result in its shutdown.

Some useful tips for assembling a shield

When assembling an electrical panel, it is necessary to use only high-quality and reliable electrical products. You should not pay attention to cheaper Chinese analogues; personal safety is much more important.

To connect wires to machines, it is best to use special lugs for crimping. Of course, then you will have to purchase pliers with which crimping is performed, but their cost is not too high.

The use of insulating tape is no longer relevant; many electricians use exclusively heat-shrinkable tubing. This consumable is convenient and reliable, and it is not necessary to purchase a hair dryer; you can use an ordinary lighter.

For ease of use, all elements of the electrical cabinet must be marked. Only then will it be possible to quickly and easily turn off the voltage in a certain room. You can make notes on the body of the device or make small signs and attach them to the product with tape.

Electricity metering board diagram 380V for a private house 15 kW

technical specifications for connection from the electricity supply company (Mosenergo, Lenenergo, Sverdlovenergo, etc., depending on the region) . It is this document that contains the main characteristics of the electrical network available to you, including the requirements for the electricity metering panel.

In this article we will examine in detail the diagram of a typical metering panel , as well as its modifications, which require collecting the requirements of technical specifications.

In such cases, the standard network parameters for connecting a private home are:

– 3 phase

– Voltage: 380V

– Power allocated: 15 kW

– Input cable: SIP 4-core (3 phase conductors and PEN)

I would like to note that one of the main tasks of technical specifications is not only to ensure the safety of the electrical installation, but also to prevent the possibility of theft of electricity by consumers.

That is why all protection or switching devices in the electrical panel located before the electric meter must be protected from the possibility of illegal connection. Usually they are hidden in separate boxes, which are sealed when connected.

In addition, the technical specifications require that the metering board be placed in a place accessible for inspection - on the border of the site, on a lighting pole or fence.

Most often, such external panels are used exclusively for accounting, without additional capabilities, and provide only basic functions. The main distribution board (PDB), in this case, is installed inside the house, where all consumers are divided into groups, the load is distributed, the appropriate automatic protective equipment is installed, etc.

All the diagrams presented below will be designed for the two most popular grounding systems in private homes TT and TN-CS . Under each connection option there will be links to step-by-step assembly instructions, with detailed comments.

If you have not decided which grounding system to choose, the following information will help you:

TN-CS is the grounding system recommended by the rules. It has a number of disadvantages; it is worth using it if you are confident in the condition of the electrical networks suitable for the house, if they are new enough and regularly maintained.

TT is a relatively safer system. The main disadvantages include only the high costs of installing protective equipment and installing a ground loop, as well as regular maintenance. Which, for safe operation, must always be maintained by you in working condition.

Review of common design mistakes

Defects in the design or planning of work entail installation errors, and this threatens disruptions in the functioning of the electrical network. The result may be the failure of expensive equipment, and even worse, an electrical injury to one of the residents.

What mistakes should you avoid:

• use low-quality products without labeling and certification;
• make one-to-one calculations - any technical products and materials must be purchased with a reserve;
• include in the project the installation of conventional sockets for connecting hobs, boilers, heat guns;
• in wooden houses, plan to use closed wiring - more complex and subject to the list of requirements of the PUE;
• design switching of low-voltage and high-power power wires in one distribution box;
• plan to connect wires using twists that are dangerous for further maintenance and operation; the best option is ready-made terminals;
• make circuits from aluminum and copper wires, and also use aluminum wiring.

Some errors relate to incorrect calculations. For example, grooves under the cable with a closed installation method should be laid to a depth of 2-2.5 cm, no less.

It is incorrect to place distribution boxes at the bottom or at human height. Their place is under the ceiling, 20 cm from a suspended structure or concrete ceiling slab

You cannot connect the grounding of sockets using a cable, or ground them on cast iron sewer or steel gas pipes.

If you do not know how to properly install electrical wiring in your home, contact the design organization. Specialists will visit the site and draw up a wiring diagram based on specific installation conditions.

A simple diagram for connecting the electrical panel of a private house 15 kW

The simplest budget option for assembling a metering board is presented below. Only the most necessary elements are used here:

2. Plastic box 3 modules, with eyes for seals

3. Three-pole Protective circuit breaker, characteristic C25 (for an allocated power of 15 kW this rating is needed)

4. Electric energy meter (meter) 3-phase 380V

5. Distribution switching block, capable of connecting wires with a cross-section of up to 16 mm2.

Scheme of a simple electrical metering panel for a private house 15 kW, TN-CS grounding system:

Simple metering panel, TT grounding system

This option is often used as a temporary one, for example, to connect a change house during construction, as it has few means of protection.

For your house in which you plan to live permanently, even for a country house, I recommend using the following assembly:

Optimal diagram of a 380V electricity metering board for a private house 15 kW

It differs from the previous one in the presence of a selective Safety Shutdown Device (number 6), it works immediately for all consumers in the house, it is also called fire protection. The installation of an RCD at the entrance to the house is recommended by the Electrical Installation Rules - PUE.

Recommended metering board diagram for a private house 380V using selective RCD, TN-CS grounding

Metering board diagram for a private house with selective RCD, For TT grounding system

This is the most balanced scheme that can be implemented for a remote electrical metering panel at home, simple and reliable. It is suitable for everyone, and this is what I recommend collecting.

To improve it, in order to enhance the protection of the electrical network and electrical appliances at home, you can add a surge protection device (SPD).

Option for an electrical panel for a private house with an SPD

Installing an SPD in the metering panel is the right decision, especially from a safety point of view.

Surge protection devices are connected in parallel to the electrical circuit (number 7), as follows:

Metering board diagram with SPD, TN-CS grounding system

Step-by-step instructions for disconnecting are available at LINK

Electrical energy metering panel with SPD, CT grounding

It is up to you to decide whether to install an SPD or not. This depends on many factors that need to be taken into account. If you decide, these diagrams will help you.

Often, in an overhead electrical panel, in addition to the above equipment, it is necessary to install some other modular devices, for example, switching devices. In particular, a conventional socket mechanism can be very useful, especially during the construction phase.

You can connect a power tool, spotlight, or any other electrical device that needs to be used outdoors. There are often no other ways to connect to the power grid.

Electrical 380V electricity metering panel for a private house with a 220V socket

In this electrical panel diagram, there is additionally a modular 220V socket (number 7) with an individual protection device - difavtomat (number 8), which combines a circuit breaker and a residual current device. The rating of the RCD must be higher than that of the circuit breaker, for example 40A, leakage current 100 or 300 mA.

Electrical metering panel 380V, with modular socket, TN-CS grounding

Electrical metering panel 380V, with modular socket and automatic circuit breaker, TT grounding

Following this example, where the outlet is protected by a residual current circuit breaker, you can install any other modular equipment, contactors, transformers, etc. to the electricity metering panel, if necessary.

Let me note again that under each diagram there are links, by clicking on which you can read the details, find out the equipment used, and ask questions.

If you know any other useful options for assembling a 380V private house metering board, write in the comments, this may be interesting and useful to many.

Otherwise, here are the main options that are used when connecting private houses and garden houses to the power grid. And most importantly, such electrical panels are successfully accepted by regulatory authorities and put into operation.

Electrical supply diagram for a private house 380V 15 kW

One of the most important stages in the construction or renovation of a country house is its electrification. In modern housing, a large number of household appliances and all kinds of equipment are installed, and all these devices consume electricity. Therefore, we have to solve such an important issue as connecting the facility to the power grid. To do this, first of all, you will need a 380V, 15 kW power supply circuit for a private house, which can be of two types - single-phase and three-phase. Both options are in demand, but recently preference has been given to a three-phase circuit, which significantly reduces the load on the network due to its even distribution in the form of three parallel lines.

What is important to know?

This diagram roughly illustrates a three-phase network:

The voltage between phases of 380 volts is indicated in blue. Green color indicates uniformly distributed line voltage. Red - voltage imbalance.

New, three-phase electricity subscribers in a private house or apartment, when connecting for the first time, should not have much hope for an initially evenly distributed load on the input line. Since several consumers can be powered from one line, and they may have problems with distribution.

The first step is to find out the voltage between the phases, as well as between L1-L3 and zero, by measuring them with a measuring device. If you started your review of our portal with this article, we recommend that you also read the instructions for using a multimeter.

Acceptable parameters for the difference in voltage on the input cable, within the permissible range of deviations described in the PUE, are up to 30% of the declared 380-400 V. In the event that the difference is greater than the permissible parameter from the regulatory document, it is necessary to contact the power supply organization to take appropriate measures to restoration of phase symmetry. Learn more about what phase imbalance in a network is. you can find out from our article.

According to the agreement between the subscriber and the RES (on the use of electricity), the latter must supply high-quality electricity to homes, with the specified phase and line voltage. The frequency must also correspond to 50 Hz.

Three-phase connection

First of all, you need to prepare all the necessary documentation. It includes technical operating conditions that are issued by the organization that supplies electricity. Based on the technical conditions, design documentation for the electrical supply of the facility is drawn up.

You will need the following documents:

• Agreement with the energy supply organization.
• Inspection report of existing electrical equipment.
• Conclusion of a laboratory study of a circuit designed for a specific object.
• The act of delimiting electrical networks by balance sheet.

The project being drawn up takes into account the specifics of further electricity consumption. All consumers are divided into groups, which include sockets and lighting systems. Each group can be switched off separately if repair work is required. At this time, the other group continues to be used without causing unnecessary inconvenience to the owners.

For all groups, calculations of the maximum power consumption of electricity are performed. In accordance with this, the most optimal cross-section of conductors is selected. As a rule, lighting lines are laid with a cable whose cross-section is 1.5 mm2, and for sockets no less than 2.5 mm2 is required. Each group is connected to automatic protective devices that prevent fires in the wiring in the event of a short circuit.

Thus, if you have a connection project, you can calculate the need for materials, instruments and equipment, as well as determine the dimensions of the electrical panel in advance. The attached diagrams mark all the places where switches, sockets, stabilizing devices and other stationary equipment are located.

Direct connection can be made underground or overhead. As a rule, in private homes the second option is used, which has a number of significant advantages. In this case, you can use any connection diagrams with minimal time spent on completing the work. During further operation, overhead lines are much easier to repair. Of great importance is the cost of connection, which is much lower than when using an underground cable line.

When making an air connection, you should take into account the distance from the house to the pole, which should not exceed 15 m. In the case where the distance is greater than this, the installation of an additional pole is required. Due to this, severe sagging or breakage of the wire under the negative influence of external factors is eliminated. You should also pay attention to ensure that the wires do not interfere with pedestrians and vehicles. The mounting height of a three-phase line is at least 2.7 m or more. The wires themselves are installed on special insulators, and only then they are brought from the pole to the power panel.

It is recommended to install the power shield on the facade of the building, then the wires go from it to all rooms. If there are electrified extensions, the supply line is also supplied to them from the panel. To connect and account for consumed electricity, a three-phase meter is required. Mostly direct switching devices are used, the operating principle of which resembles a single-phase meter. In this case, you just need to correctly follow the device connection diagram located on its back cover or in the technical data sheet.

In some cases, a semi-indirect connection scheme for a three-phase meter can be used in a private house. The connection diagram is supplemented with a voltage transformer. To pay for consumed electricity, the device readings must be multiplied by the transformation ratio indicated on the transformer.

Connecting 380 volts in a private house: diagram and some requirements

Having a connection project in hand, you can begin basic calculations: how much material, equipment and instruments will be required. Also determine the dimensions of the electrical panel and all its constituent devices and elements.

The three-phase connection of a detached house is as follows: four wires, one of which is zero, and the other three are working phases, supply voltage to the house from the transformer.

The principle of this connection is based on: all the conductors have the ability to connect to the water device of the entire building, and only from it does electricity flow to the multi-tariff meter and then to the distribution board. From this power panel, which is located on the facade of the house, wires go for internal connection of all rooms.

The connection diagram determines the location of the following elements:

• Switches;
• Sockets;
• Stabilizing devices;
• Stationary equipment.

The most important thing is to make the correct and competent connection of all input cables, common lines and additional electrical panel devices. This device is important and necessary for the entire three-phase system circuit. Before installing a switchboard, you need to know some of its features. This device must be located only in a freely accessible place, and its model must correspond to the type of room. Its compliance with the electrical wiring of the entire house also plays a very important role.

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Single-line power supply diagram for a private house

When developing the power supply for private houses, a single-line diagram is most often used as the most optimal option. It allows for simple design and installation, even in-house. The single-line diagram has proven itself to be effective and easy to use. At its core, it is a highly simplified circuit diagram, where all types of connections and network laying are made with one line of the same thickness. This is where the name single-line diagram came from.

There are two options for single-line diagrams - calculation and executive. The first option is used in the process of building a house. This diagram determines the procedure for installing cable lines at a specific facility and the selection of protective equipment. Calculations of all power loads on this network are preliminarily performed. The calculated single-line diagram indicates all available powers and their values. The location of the ASU must be noted and electrical panels must be marked.

The executive diagram is carried out for existing electrical installations when the house has already been built. By this time, the results of a building survey have already been received from the design organization to prepare the most suitable location of all elements and power supply devices.

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Single-line diagram of the panel of an apartment and a private house: designated elements

A single-line diagram made for any residential property must necessarily comply with all GOST standards. The shield diagram must be carried out in accordance with all uniform standards. This distribution panel diagram is mandatory and is attached to the project.

Having a single-line diagram available, you can find out the entire power of the proposed power supply for a house or apartment. It will also indicate all the components of the electrical panel.

This diagram should graphically indicate the three phases and input group circuits, which will certainly depart from the main supplies. To do this, draw a line - this will be the power phase, which is indicated by a number. Next to it you need to put a crossed out stroke, it will be responsible for its definition.

Single-line diagram of the panel of an apartment and a private house

Key parameters that make up the power supply system:

• A point that indicates the connection of an object to the electrical network;
• Device responsible for input and distribution;
• Sometimes the shield itself and its parameters;
• Input power cable, indicating its brand and cross-section;
• Group circuits.

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Each circuit and group lines must be protected from overloads and electrical short circuits. Therefore, it is necessary to indicate on the electrical panel diagram the presence of circuit breakers: RCDs, switches, contactors.