How to calculate electrical wiring in an apartment. How much cable do you need to supply electricity to a house or apartment? Calculation of the number of wires in the house

Making an electrical wiring system on your own will not be easy if you don’t know what materials to use and how to calculate their quantities. When working with electricity, you should be extremely careful - there is always a risk of making a mistake, buying more or less wires and accessories than you need, choosing wires with the wrong cross-section or positioning them incorrectly. In this article we will tell you how to calculate electrical wiring in an apartment and in a private house.

Before you start calculating the length of electrical wiring and running around the house with a tape measure, it would be nice to figure out which wires can be laid in a residential building, which of them are suitable for open and closed wiring, and can they even withstand the power of all electrical appliances? In other words, before starting practice, you need to study the theory.

Cable or wire?

Most people do not see the differences between cable and wire and use these words as synonyms. Yes, these products are similar, but their purpose, functions and technical characteristics are completely different.

So, the first difference becomes noticeable even in the store - the wire is cheaper than the cable. However, the defining differentiating factor is the specification of the products. A wire is a conductor of electricity with very thin insulation or no insulation at all. It may consist of one or more cores.

Important point: The wires are only suitable for installing hidden electrical wiring, and the cable can be laid openly.

A cable is a whole system of conductors, each of which has its own insulation. All these cores are collected together and surrounded by a common, denser insulation. In other words, a cable is a lot of insulated wires. It is not surprising that its cost is several times higher.

Number of wires

An electrical wiring diagram will help you determine the required number of wires, but if the house is being built from scratch and there is nothing like that in it, you will have to work with a tape measure. When taking measurements, take into account all corners and niches, or even better, make markings with a simple pencil in the places where wires and cables will be laid.

Another important point is to take into account all the electrical appliances that will be used in the house, plus a small reserve in case you want to buy a second TV, computer, toaster or coffee machine. As a result, you will get a certain number. Multiply this by 15% to have a standard supply of material “just in case” or for future repairs.

If you are planning to do electrical wiring in a wooden house on 2-3 floors, then crawling around it with a tape measure will be very tiring. In the case of large areas, you can go the other way - multiply the total area of ​​​​all rooms, including non-residential ones, by 2. For example, if the area is 90 m², then for wiring you will need 180 m of wires and a reserve of 27 m. It seems that this is a lot, but it only seems. However, this method only gives an approximate figure, so there is a possibility that there may not be enough material.

There is also another problem - to lay electrical wiring in a private house, you may need more than one type of wire. How to be in this case? You can take a risk and divide the total amount of material required by 2 - part will go to power supply, part to lighting. But don’t forget about electric stoves, washing machines, climate control equipment - such devices require three-core cables, which also needs to be taken into account.

What wires are needed?

Once you have dived headlong into calculating electrical wiring, it becomes clear that measuring the length of the walls and going out to buy some wire is not enough. It turns out that there are a lot of types of wires and cables, and you need to be able to distinguish them and select them correctly. So, we smoothly approached the topic of types of electrically conductive products.

As you already know, they can include one core, two, three or more. The cores, in turn, can be single- or multi-wire. The shell is not just for insulation - different markings and colors make it easy to distinguish between models.

VVGng cable is often used for household electrical wiring, but PUNP or NYM are also suitable for this purpose. It is better to choose the latter for safe connection to the panel on the site in an apartment building. It is also suitable for organizing a separate connection of powerful devices. They can generally completely do the power wiring, but due to its high cost (more expensive than the products listed above), it is used in rare cases.

Good to know: If you see the letters “ng” in the marking, then the insulation is made of fire-resistant plastic, which, in the event of a wiring fire, allows you to localize the source of the fire.

Let's consider the main types of products that are suitable for laying electrical wiring in a private house and apartment:

Previously, aluminum wires marked APV, APRTO and APPV were laid everywhere, but now there are more reliable, functional and safe products.

When calculating electrical wiring in a house, you should adhere to the requirements of the PUE for painting insulation. Thus, the neutral conductor is always blue, and the protective neutral conductor is green-yellow. The color of the phase should always be different from the color of the neutral conductor. There are many options - red, brown, white, black, etc.

One phase or three?

Owners of many Soviet-built private houses very often encounter this problem - the network cannot withstand the voltage. You turn on the electric kettle, washing machine and computer - the lights turn off. The fact is that before people did not have so many household electrical appliances, and what can I say - not everyone had a TV! That’s why a single-phase input cable, as they say, was enough. Today the situation is different, and in the kitchen alone you can count at least 5 appliances, without which we cannot imagine a comfortable life.

If you think that having a three-phase network, you will be able to turn on more devices, this is true, but with a slight adjustment. Single-phase networks can also be designed for 10 or even 15 kW, so you may not get any benefit when calculating electrical wiring based on power. Where three-phase networks really differ is the input cable with a small cross-section. Since the current flows through 3 phases instead of one, the wire experiences less load, and therefore the rating of the input switch will be less. At the same time, the distribution panel for a three-phase network will be large, since the meter itself is larger than a single-phase one and the circuit breaker will require 3-4 modules.

Advantages of three-phase input:

1. Distributing the load between phases avoids the effect of phase “misalignment”.
2. Small cable cross-section.
3. Possibility of connecting high power devices.
4. Possibility of increasing the maximum permitted power consumption (if the energy sales company allows it).

One of the disadvantages is the fact that in order to carry out a three-phase input or replace a single-phase one, you will have to seek permission from the energy company. Most often, even with a loyal attitude on its part, it is not possible to modernize the network. In addition, high voltage increases the risk of electric shock, so when installing wiring in a private house, especially if it is wooden, it is better to install a three-pole circuit breaker and surge suppressors in the panel immediately before the input.

If we summarize all the above facts, it becomes clear that three-phase input is suitable for large private houses with an area of ​​100 m² and in cases where you plan to connect powerful electrical receivers. For a small country house or apartment, one phase is sufficient.

Let's do the calculation

Any household electrical wiring in an apartment or private house starts with an input cable, which bears the entire load from appliances and lighting. To choose this cable, you need to calculate the cross-section in accordance with all the equipment in the house, so first you will have to make a complete list of them. This includes refrigerators, televisions, computers, microwaves, table lamps, climate control equipment - in general, everything that requires an outlet.

Each household appliance has its own power, and you need to find out the total power value, then multiply this number by 0.75 (coefficient). The power can be viewed on the device itself (usually there is a sticker with the necessary technical information on the bottom or back of the case). The table below includes the most common household appliances and their power consumption:

Having found the desired value, selecting the cable cross-section is not difficult. For this, there is another table that shows the dependence of cable cross-section, power and voltage. It displays data for copper cables, since no one uses aluminum cables today.

By the way, why did they abandon the use of aluminum cables and wires for electrical wiring, because similar systems worked before, and everything was fine? If you look at it, aluminum as a material is excellent for making wires - it is lightweight, conducts electricity well, is not subject to corrosion, and is completely indispensable when installing power lines. However, there is one big “BUT” that put an end to the use of aluminum wires - high electrical resistivity (2 times higher than copper). Simply put, to ensure the same conductivity, you need an aluminum conductor that is many times more powerful, and therefore heavier, than when working with copper.

Another disadvantage is that as a result of oxidation upon contact with air, a characteristic film is formed on the surface of the aluminum product, which deteriorates its quality as a conductor. At the point of electrical contact with such an oxide, increased contact resistance may occur, the contact will heat up and further increase the electrical resistance, and the wiring will burn out as a result.

But let's return to calculating the cross-section of the electrical wiring. When you have figured out the input cable, you can proceed to calculating the cross-section of cables and wires for sockets and lighting fixtures. Based on the data in the table, it becomes clear that 0.5 mm² wires should be used for lighting, and 1.5 mm² for sockets. But often more powerful wires are installed: for lighting, at least 1.5 mm², and for sockets - from 2.5 mm², if, of course, the power of the devices matches the technical characteristics of the wire.

For example, as you can see in the table, if the network voltage is 220 V, then a wire with a cross-section of 2.5 mm² will withstand a voltage of up to 27 A or 5.9 kW. In such a situation, in order to protect electricity consumers and wires, it is recommended to install a special machine with a maximum operating current of no more than 25 A.

In addition to calculating the electrical wiring load, it is necessary to take into account the length of the end-user power line. Again, we will use the table and determine the cross section for other types of load. When designing and installing wiring, do not forget about the selectivity of the machines.

Wherever you calculate the electrical wiring load - in a private house or apartment, remember that such work does not tolerate negligence, and mistakes can lead to big troubles. If you are not confident in your capabilities, it is better to entrust this to professional electricians.

Today, it is impossible to imagine any room without electricity supply. Often, in industrial, commercial and multi-storey residential buildings, the laying of electrically conductive cables is carried out by a construction company. At the same time, specialists carry out preliminary calculations of the conductive network. But, if you want to repair the wiring in an apartment with your own hands, or lay a network of electrical wires in a private house or country house, then you will have to carry out the calculations yourself.

Correct calculation of wiring in an apartment and private house

Calculation of wiring, both in an apartment and a private house, includes determining the types, length and cross-section of conductive cables. The serviceability of the system, the safety of property and the lives of residents depend on how correctly the wires are selected.

To do this, you need to decide how many and what appliances in the house will work simultaneously (for example, a refrigerator, electric stove, microwave oven, boiler). After this, you need to find out what power each device is designed for. At the same time, the power of lighting devices should also be taken into account. This can be done by finding a technical data sheet for electrical devices or a power table on the network. After this, all powers must be added up. Knowing the total power consumption of all electrical appliances in the house and the voltage in the network, it will be possible to calculate the amount of current that the cable will have to withstand and determine the cross-section of the wire.

How to calculate wiring in a house: select the cable cross-section

Why do you need to know the cable cross-section? The reliability and safety of the wiring directly depends on this indicator. Thus, an incorrectly selected cross-section (lower than the calculated one) will not correspond to the load on the system, and can cause fires. Cables with a cross-section larger than the calculated one will create difficulties during electrical installation. In addition, such wires are more expensive. Therefore, electrical wiring “in reserve” will negatively affect the construction estimate.

The cross-section of the cable for installing electrical wiring in a private house is equal to the ratio of the total power of all electrical appliances to the mains voltage.

Often, single-phase electrical networks are used in private homes. The voltage of such networks is 220 V. In three-phase networks the voltage is higher and equal to 380 V.

When choosing the cross-section of conductive cables, you must use the following recommendations:

• To create a safety margin, the power consumption of household lighting and electrical appliances should be multiplied by a constant factor of 1.5;
• The power cable leading to the outlet must have a cross-section equal to 2.5 square meters. mm;
• For lighting fixtures, a 1.5 sq. cable is suitable. mm;
• For electrical appliances with higher power, it is necessary to choose a wire cross-section that is equal to 6 square meters. mm (it is designed for a load of 8000 W);
• For a single-phase hidden type installation, the cross-sectional area of ​​the wire must be doubled;
• The cable cross-section should be increased by 1.5 times when laying a three-phase network is closed;
• When using aluminum wires, it is necessary to take their cross-section with a reserve, since their ability to withstand high current loads for a long time is lower than that of copper wires.

To obtain the most accurate calculations of the cross-section of cables and wires, it is also necessary to take into account the type of conductor insulation and the number of cores in the cable. To obtain safe wiring, you must follow the Electrical Installation Regulations. A special online program will help you calculate the cross-section of cables for wiring electricity to a storey building.

Calculation of cable length: how many meters for a 5-storey building

After calculating the cross-section of cables and wires, you need to find out how much material is needed for wiring installation. An electrical wiring diagram created based on the house plan will help you determine the cable consumption.

The location of electrical installations in the circuit when designing electrical wiring must meet the requirements of SNiP 31-02 of 2001 and part 5-52 of GOST “Low-voltage electrical installations”.

If the building was recently built or is under construction, you will have to determine the length of the electrical wiring manually. This can be done using a tape measure.

When measuring the length of electrical wiring, you must follow these recommendations:

• The layout of the future network of electrical wires can be outlined using a pencil or coal;
• When measuring the length with a tape measure, you should take into account the methods of penetration and switching of wires;
• It is necessary to measure protrusions, niches, corners;
• The resulting value should be multiplied by 15% - this is a standard coefficient for technical calculations.

Calculation of cable consumption over large areas (for example, a house with 3-5 floors) can be done using mathematical calculations. So, the area of ​​​​all rooms in the building (both residential and non-residential) must be multiplied by 2. The technical reserve should be added to the resulting value. So, for example, a house with an area of ​​330 square meters will need 759 meters of cable. The number of internal power lines in a multi-storey apartment building directly depends on the number of rooms in the apartment. So, for electrical wiring in a one-room apartment you will need less cable than, for example, in a three-room apartment. For example, about 100-105 meters of cable will be needed for electrical wiring for a two-room apartment.

Length of the main power cable in a high-rise building: how many meters for a 10-story building

Calculating the length and cross-section of the main power cable in a multi-story building may be necessary when repairing electrical wiring. Thus, residents of old apartments often change the wiring in favor of a more powerful one. At the same time, the voltage on the power cable increases. Because of this, the cable heats up and becomes unusable. A reasonable question arises about replacing the main power cable in the entrance with a cable with a larger cross-section. The main problems that residents may encounter are obtaining permission from the utilities of the housing department or homeowners association, the queue for the repair team to fulfill the application, and the cost of the cable itself.

Since the main cable runs only from the ASU to the top floor, calculating its length will not be difficult: it will be equal to the height of the house, taking into account the necessary technological clearances.

For a ten-story building, the cable length will be about 35 meters. But all these preliminary calculations can only be used to calculate the estimated cost of the cable. The exact length and cross-section should only be obtained from employees of the relevant utility company to which your home belongs.

Competent calculation of electrical wiring (video)

Calculation of electrical wiring is a complex undertaking that involves calculating the total consumed load of all lighting and electrical devices, determining the material of manufacture and cross-section of wires, and the length of the electrical wire network. When calculating electrical wiring, it is necessary to take into account the number of power-consuming equipment, its power, type and voltage in the electrical network. At the same time, it is necessary to take into account the requirements of PUE, SNiP and GOST. Only then will the electrical wiring be reliable and safe.

Wire cross-section, however, without this it will not be possible to correctly calculate the electrical wiring. If you live in a multi-storey apartment building, then there is no need to lay communications - the builders did it for you. But when building a private house, you will have to do it yourself.

During the construction of a private house, the question will definitely arise about how to calculate the electrical wiring

Where to begin?

Today it is hardly possible to imagine modern life without electricity. Even the most ardent nature lover will not be able to do without light, an electric kettle, a computer, and so on for long. What can we say about those people who are used to living in absolutely comfortable conditions? Today, almost no household appliance can operate without electricity. You cannot choose wires at random to stretch them throughout the house to connect electricity. You need to know how to calculate the cross-section of a wire, what kind of wires there are, and so on. This is exactly what we will talk about in this article.

Based on power and current, you can determine which wires you will need to supply electricity to your home. Even from a school physics course, I remember the formula for power (P), which can be established by multiplying voltage (U) and current (I):

If you have two values, you can easily set a third one. You should also be guided by the electricity load (current strength) on the wire. This parameter must be taken into account in any case, because a wire with too little thickness can simply burn out under increased load. At this voltage, different types of wires can support different amounts of power.

Calculation of wiring outside the home

If you live in a private house, you have probably thought more than once about how you can decorate your garden space. One option is to install outdoor lighting fixtures. Some people use flashlights with solar panels, while others run electrical lines. The wire can be laid either deep underground, using dielectric pipes, or above it.

There are several types of connection:

• single-phase;
• two-phase;
• three-phase.

On the site it directly depends on the type of water supply from the house. In most cases, a two-wire system is sufficient for minimal electricity consumption. One will be a phase, the other will be a zero. There are situations when three wires are needed to connect the cable from the house to the site. The third plays the role of the second phase. If you have a power source on your site, such as a transformer or machine, you will need to use a three-phase wiring method. Such a four-wire input is permissible only after the appropriate permission from the organization that supplies you with electricity.

Let's consider a single-phase two-wire connection on a house site. First, let's give a few recommendations:

• Before starting calculations, it is necessary to take into account the length of the cable. If the distance from the source to the site exceeds 25 meters, then it will be necessary to erect additional fastening for the wire. If your area experiences significant winds, then this distance should be reduced to 15–20 meters;
• if the cable passes over the roadway, its height must be at least 6 meters above the ground;
• It is recommended to connect the line to the house at a height of at least 3 meters.

As you know, current leaves the transformer at a voltage of 220 V. But there are situations when voltage drops occur, and much less can reach you - about 150 V. Stabilizers are created for this. where the electricity comes out. Also equip the system with network overload protection circuit breakers. The distribution panel must be located in a dry place.

You can lay the wire both underground and directly through the air. The latter option will be much more economical. In the case of lanterns along paths, it is better to get by with underground cable laying. Light bulbs must be connected in a parallel circuit. This way you will exclude the possibility of the lack of all lighting as a result of one of them burning out.

Wires, take a site plan and mark all underground and overhead electrical transmission lines. Sum up their lengths and multiply by two. This is necessary because you will need two wires.

Calculation of electrical wiring in the apartment

First of all, you need to remember that the calculation of electrical wiring in an apartment begins with drawing up a wiring diagram. If you decide to do the wiring yourself, you need to pay special attention to the following issues:

• determination of the cross-section of wire cores;
• under what conditions the wire will be laid;
• how to connect the meter;
• grounding;
• total ;
• power grid protection.

An average one-room apartment requires a total power of 15 kW. It is more convenient to calculate power consumption if you conditionally divide the wiring into several groups. For example, sockets for:

• bathroom;
• rooms;
• kitchens;
• corridor.

And please take into account separately. This will make it easier for you to calculate the maximum load of electrical appliances in your home. If in doubt, use a special calculator that you can find on the Internet in construction forums.

In multi-storey buildings, communications are laid by the builders, and there is no need to install the electrical network yourself, but if you are building a house, electrical wiring calculation will definitely be needed.

Where does the electrical wiring calculation begin?

Scientists still have a rather vague idea of ​​what current is. It is known how to use it, it is known how to change it, how to direct it, but all its properties and features have not been solved. However, today it is impossible, or very difficult, to do without a stream of electrons running along a cable, especially for those who are accustomed to comfort. Light, heat, fresh conditioned air, communications, and often cooking - all this provides us with electricity, which powers all kinds of household and industrial equipment. In order for current to start flowing into a house or area, it is not enough to simply stretch the wires; you need to know exactly what material they should be made of and what cross-section. But let's take things in order.

Electrical wiring calculation

Using the buttons, draw up a diagram of the planned electrical network.

The wire goes:

Wire used Copper Aluminum

Exit from the counter
Add a wire going to...

Calculate wire cross-sections -

It is also known from a school physics course that current has parameters such as power, voltage and, in fact, a certain force determined by the intensity of movement of charged particles. It is recommended to start calculating electrical wiring with the ratio of these quantities, which influence many factors when choosing a cable and other network elements. The formula looks like this: P = I U, Here P– power, measured in Watts (W and kW), I– current strength (Amps, A), U– voltage (Volts, V). Based on the formula, you can find any parameter if the other two are known.

The cable cross-section is directly related to the current strength. If you take a wire 0.5 mm2 thick and pass 17 Amperes of electricity through it, the wiring will simply burn out, since with such a current strength you need a copper or aluminum core of 1 mm2. In addition, its ability to maintain a certain power at a particular voltage depends on the cross-section and material of the cable. The following is a table that will help you select the required wire diameter for various network options.

Dependence of cable cross-section on current strength

Open wiring

Closed wiring

Cable cross-section mm²

Copper

Aluminum

Copper

Aluminum

Current A

Power, kWt

Current A

Power, kWt

Current A

Power, kWt

Current A

Power, kWt

How to calculate electrical wiring on a site

In the local area, along, sometimes even in the garden and flower bed, as well as along the perimeter of the site, there is always some kind of lighting. And if some particularly economical owners find it more convenient to use solar-powered lanterns and decorative lamps, then traditionally power lines from the nearest substation are stretched to the land plots. This can be an overhead cable or underground; in the first case, it passes through insulators on the tops of the poles, and in the second, through a special dielectric pipe buried deep in the ground.

Based on how electricity is supplied, it is necessary to calculate the continuation of the line on the site. The simplest solution is from two wires, one of which is phase and the other neutral, sometimes a house may have three wires to provide two separate phases. A four-wire input is necessary if there is a need for a three-phase version, if there is an appropriate consumer (industrial and professional equipment, machine tool). The latter type of connection can only be used after obtaining permission from the electricity supply organization.

So, let's focus on a single-phase two-wire connection to the substation, which still needs to be extended if you do not want to pay for the work of specialists. Before calculating the electrical wiring, you should take into account that the length of the cable from the common line to your site should not exceed 25 meters; at a greater distance (and in case of strong winds in your area and at a shorter distance) you need to install a support. The height of the cable above the road is at least 6 meters; it is advisable to install an overhead line into the house at a level of 3 meters.

At the output from the substation where the transformer is located, the current usually already has a voltage of 220 V. But drops in the electrical network are common, and it may turn out that some 160 V is coming to you. To obtain the required voltage level, you need to install a stabilizer, as well as circuit breakers that will protect the network from overload. Their parameters are indicated in Amperes, that is, they are measured against current consumption. Having completed the distribution panel, we place it in a place where there is no dampness.

Wires are extended to all outbuildings, be it a barn or a summer house; this can be done by air or directly, which will be more economical. It is better to provide lighting along the paths with an underground cable, and the lights should be connected in parallel rather than in series, so that the burnout of one lamp does not turn off the entire circuit. We take a plan, and on it we mark the overhead line connecting the buildings with the distributor, and the underground cable stretching from it along the paths (and repeating all their bends). We measure the resulting wiring and multiply its length by 2, since at least two wires are needed (double insulation is recommended outdoors), for phase and zero.

Home wiring calculator

To begin with, we calculate the power of the machine for all current consumers present and switched on simultaneously. If you have a refrigerator and a computer running, and you also run a washing machine, which requires an instantaneous water heater and a pump to supply water, then the consumption will be about 11 kW. This is even if we exclude lighting. It is logical that a 16 A machine will not withstand such a load. You can see what power these or other devices have in the following table; then, using the above formula, we calculate the rating of the machine.

Power of electrical appliances (W)

Hair dryer	1200	Drill	800
Iron	1700	Hammer	1200
Electric stove	3000	Electric sharpener	900
Toaster	800	Circular Saw	1300
Coffee maker	1000	Electric planer	900
Heater	1500	Jigsaw	700
Grill	1400	Grinder	1700
Vacuum cleaner	1600	Water heater	5000
Printer	100	Washing machine	2500
TV	300	Compressor	2000
Fridge	300	Water pump	1000
Microwave	1400	A circular saw	2000
Computer	500	Air conditioner	1500
Electric kettle	1200	Electric motors	1500
Full coverage	1000	Fans	1000
Boiler	1500	Lawnmower	1500
Air fryer	1700	Welder	2300
Radio	70	Concrete mixer 70 liters	250
Treatment plant compressor (WTP)	200	Infrared heater	600

To install the electrical network, branch boxes are used, from which the wiring is pulled into adjacent rooms.

It should be remembered that when wiring the electrical network around the house, you must immediately divide it into three groups, one of which is allocated entirely for lighting fixtures, the second for sockets, and the third is used for devices that require grounding. This will make it easier to calculate the electrical wiring calculator. In this case, in no case should you use one neutral cable for two different groups, as well as combine them with each other. It is also necessary to provide each individual group with its own automatic protective switch, the rating of which is calculated from the sum of the powers of the devices connected to this wiring.

This article will tell you how to calculate the wire cross-section based on power consumption yourself. You need to know this not only when working in the house, but also when carrying out work on cars, for example. If the wire cross-section is insufficient, it will begin to heat up very much, which will lead to a significant loss of safety level. Taking into account all the recommendations that will be outlined below, you will be able to independently calculate the parameters of the wires for installing electrical power in the house. But if you are not confident in your abilities, it is better to contact specialists in this field. Moreover, it should be noted that the calculation of the wire cross-section based on power consumption (12V and 220V) is carried out in the same way.

Calculating the length of electrical wiring

For any type of electronic system, the most important condition for stable and trouble-free operation is the correct calculation of the cross-sections of all wires in terms of current and power. The first step is to calculate the maximum length of the entire electrical wiring. There are several ways to do this:

1. Measuring the distance from panels to sockets and switches according to the installation diagram. Moreover, this can be done with a ruler on a pre-prepared electrical wiring plan - just multiply the obtained length values ​​by the scale.
2. And the second, more accurate way is to arm yourself with a ruler and walk through all the rooms, taking measurements. Moreover, you need to take into account that the wires must somehow be connected, so there should always be a margin - at least one or two centimeters from each edge of the wiring.

Now you can proceed to the next step.

Calculation of wiring load

To calculate the total load, you need to add up all the minimum power of consumers in the house. Let's say you are making calculations for a kitchen; it has lamps, a microwave oven, an electric kettle and stove, a dishwasher, and so on. All powers must be summed up (look at the back covers for power consumption, but you will have to calculate the current yourself using this parameter). Then multiply by a correction factor of 0.75. It is also called the simultaneity coefficient. Its essence is clear from the name itself. You will need this figure, which is obtained as a result of calculations, in the future to carry out calculations of wire parameters. Please note that the entire electrical system must be safe, reliable and durable. These are the basic requirements that must be taken into account when calculating the wire cross-section based on power consumption of 12V and 220V.

Current consumption of electrical installations

Now let’s talk about how to calculate the current consumption of an electrical appliance. You can do this in your head, or you can do it on a calculator. See the instructions for the device to see what power consumption it has. Of course, an alternating current with a voltage of 220 volts flows in a household electrical network. Therefore, using a simple formula (power consumption divided by supply voltage), the current can be calculated. For example, an electric kettle has a power of 1000 W. This means that if we divide 1000 by 220, we get a value approximately equal to 4.55 amperes. It is produced very simply in terms of power consumption. How to do this is described in the article. In operating mode, the kettle consumes 4.55 amperes from the network (for protection it is necessary to install a circuit breaker of a higher rating). But note that this is not always the exact value. For example, if the design of an electrical appliance has a motor, you can increase the obtained value by approximately 25% - the current consumption of the motor in the starting mode is much greater than during idling.

But you can use a set of rules and standards. There is such a document as the Electrical Installation Rules, which regulates all the rules for installing wiring not only in private property, but also in factories, factories, etc. According to these rules, the electrical wiring standard is the ability to withstand a load of 25 amperes for a long time. Therefore, in apartments, all electrical wiring should be done only using copper wire, its cross-section is at least 5 square meters. mm. Each core must have a cross-section of over 2.5 square meters. mm. The conductor diameter should be 1.8 mm.

To ensure that all electrical wiring operates as safely as possible, a circuit breaker is installed at the input. It will protect the apartment from short circuits. Also, recently, most homeowners have been installing residual current devices, which instantly change the resistance in the circuit. In other words, if you accidentally touch a live one, they will immediately de-energize and you won't get hit. it is necessary to calculate the current, and be sure to choose with a reserve so that it is always possible to install any electrical appliance in the house. Proper calculation of the wire cross-section according to power consumption (you will learn how to make the right choice of wires from this material) is the key to ensuring that the power supply will function correctly and efficiently.

Materials for making wires

As a rule, installation of electrical wiring in a private house or apartment is done using three-core wires. Moreover, each core has separate insulation, they all have different colors - brown, blue, yellow-green (standard). The core is the part of the wire through which current flows. It can be either single-wire or multi-wire. Some brands of wire use a cotton braid over the cores. Materials for making wire cores:

1. Steel.
2. Copper.
3. Aluminum.

Sometimes you can find combined ones, for example, stranded copper wire with several steel conductors. But these were used for field telephone communication - the copper ones transmitted a signal, and the steel ones were used for the most part for attaching to supports. Therefore, this article will not discuss such wires. For apartments and private houses, copper wire is ideal. It is durable, reliable, and its performance is much higher than that of cheap aluminum. Of course, the price of copper wire is steep, but it is worth mentioning that its service life (guaranteed) is 50 years.

Wire brands

For electrical wiring, it is best to use two brands of wires - VVGng and VVG. The first one has the ending “-ng”, which indicates that the insulation does not burn. It is used for electrical wiring inside structures and buildings, as well as in the ground, in the open air. Operates stably in the temperature range -50... +50. Guaranteed service life - at least 30 years. The cable can have two, three or four cores, each with a cross-section in the range of 1.5... 35 sq. mm. Please also note that it is necessary to calculate the wire cross-section based on power consumption and length (in the case of a long overhead line).

Make sure that there is no letter “A” before the name of the wire (for example, АВВГ). This suggests that the cores inside are made of aluminum. There are also foreign analogues - the NYM brand cable, which has a round shape, meets the standards adopted in Germany (VDE0250). The conductors are copper, the insulation is not subject to combustion. The round shape of the wire is much more convenient if it is necessary to install through the wall. But for wiring indoors, flat domestic ones turn out to be more convenient.

Aluminum wires

They are light in weight and, most importantly, low in cost. Therefore, they are useful for those cases when you need to lay long lines through the air. If all work is carried out competently and correctly, you will get an ideal air line, since aluminum has one huge advantage - it is not susceptible to oxidation (unlike copper). But aluminum wiring was often used in houses (usually old ones). The wire used to be easier to get, and it cost a penny. It should be noted that calculating the wire cross-section based on power consumption (the features of this process are known to every electrician) is the main stage in creating a home power supply project. But you need to pay attention to one feature - the cross-section of the aluminum wire must be larger than copper in order to withstand the same load.

Table for calculating power cross-section

It should also be mentioned that the maximum permissible current load is much less than for copper ones. The table below will help you calculate the core cross-section

Wire cross-section depending on the type of wiring

There are two types of installation of electrical wiring in houses - open and closed. As you understand, you need to take this nuance into account when making calculations. Hidden wiring is installed inside ceilings, as well as in grooves and channels, in pipes, etc. Closed wiring has higher requirements, since it has less cooling capacity. And any wire, when exposed to a heavy load for a long time, heats up very much. Therefore, when calculating the wire cross-section based on power consumption, be sure to take into account the effect on heating. The following parameters must also be taken into account:

1. Long-term current load.
2. Loss of voltage.

As the wire length increases, the voltage decreases. Therefore, in order to reduce voltage losses, it is necessary to increase the cross-section of the wire cores. If we are talking about a small house or even a room, then the value of losses is extremely low and can be neglected. But if a long line is being calculated, there is no escape from this. After all, the calculation of the wire cross-section based on power consumption (the influence of length is very large) depends on such a parameter as the length of the line.

Wire power calculation

So, you will need to know the following characteristics:

1. The material from which the cable cores are made.
2. Maximum power consumption.
3. Supply voltage.

Please note that when any current flows, the temperature rises and some heat is released. Moreover, the amount of heat is proportional to the total power that is dissipated on a piece of electrical wiring. If you choose the wrong cross-section, excessive heating will occur, and the result can be disastrous - ignition of the electrical wiring and fire. Therefore, it is worthwhile to accurately calculate the wire cross-section based on power consumption. The risk factors are too great and too many.

Optimal parameters

Optimal sections:

1. For wiring sockets - 2.5 sq. mm.
2. Lighting group - 1.5 sq. mm.
3. High power electrical appliances (electric stove) - 4-6 sq. mm.

Please note that copper wires can withstand the following loads:

1. Wire 1.5 sq. mm - up to 4.1 kW (current load - 19 amperes).
2. 2.5 sq. mm - up to 5.9 kW (current - up to 27 amperes).
3. 4-6 sq. mm - more than 8-10 kW.

Therefore, when the load increases, you will always have a fairly large reserve.

Conclusion

Now you know how to calculate the cross-section of a wire based on power consumption (you now know the definition of important characteristics and other small factors). Based on all the above data, you can independently, without resorting to the help of professionals, draw up a correct power supply plan for your home or apartment.