Calculation of the cross-section of the wire according to the power consumption. Calculation features

This article will tell you how to calculate the cross-section of the wire by the power consumption yourself. You need to know this not only when installing electrical wiring in the house, but also when carrying out work in cars, for example. If the cross-section of the wire is insufficient, it will begin to heat very much, which will lead to a significant loss of safety. Considering all the recommendations that will be set out below, you will be able to independently calculate the parameters of the wires for the installation of electricity in the house. But if you are not confident in your abilities, it is better to consult specialists in this field. And it should be noted that the calculation of the wire cross-section for the power consumption (12V and 220V) is made similarly.

Carrying out of calculation of length of electroconducting

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 for current and power. The first step is to calculate the maximum length of the entire wiring. There are several ways to do this:

1. Measuring the distance from the flaps to the sockets, switches according to the wiring diagram. And you can do it with a ruler on a pre-prepared plan for wiring - you can 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. And you need to take into account that the wires must somehow connect, so there should always be a supply - at least one or two centimeters from each edge of the wiring.

Now you can proceed to the next step.

Calculation of the load on the wiring

To calculate the total load, you need to add up all the minimum power of consumers at home. Let's say you spend the calculation for the kitchen, it has fixtures, a microwave oven, an electric kettle and a stove, a dishwasher and so on. All power must be summed up (see the power consumption of the rear covers , but you will have to calculate the current by yourself for this parameter). After multiplying by a correction factor of 0.75. It is also called the simultaneity coefficient. Its essence is clear from the name itself. This figure, which will be obtained as a result of calculations, you will need to continue to conduct calculations of the parameters of the wires. Please note that the entire power supply system must be safe, reliable and durable. These are the main requirements that must be taken into account when calculating the cross-section of the wire according to the power consumption of 12V and 220V.

Current consumption of electrical installations

Now about how to calculate the current consumption of an electrical appliance. You can do this in the mind, but you can also on the calculator. See the instructions to the device, what is the value of the power consumed from it. Of course, AC power is running at AC 220 volts. Therefore, using a simple formula (the power consumed divided by the supply voltage), you can calculate the current. For example, an electric kettle has a power of 1000 watts. So, if we divide 1000 by 220, we get a value of about 4.55 amperes. It is very simple to calculate the cross-section of the wire according to the power consumption. How to implement this, described in the article. In the operating mode, the kettle consumes 4.55 amperes from the mains (a larger circuit breaker must be installed for protection). But notice that this is not always the exact meaning. For example, if there is an engine in the design of the appliance, it is possible to increase by about 25% the value obtained - the current consumption of the motor in the starting mode is much greater than during idling.

REC recommendations

But you can use a set of rules and standards. There is such a document as the Rules for the installation of electrical installations, it is he who regulates all the norms of conducting wiring not only in private domains, 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 wiring should be carried out only using a copper wire, its cross section - not less than 5 square meters. Mm. Each core should have a cross section of more than 2.5 square meters. Mm. The conductor diameter should be 1.8 mm.

To ensure that all wiring works as safely as possible, an automatic circuit breaker is installed at the input. He will protect the apartment from short circuits. Also recently, most owners of residential areas are installing protective circuit breakers, which immediately act to change the resistance in the circuit. In other words, if you accidentally touch exposed wires under stress, they will instantly be de-energized and you will not get hit. Circuit breakers must be calculated according to the current, and it is necessary to choose with a reserve, so that it is always possible to install an electrical appliance in the house. A competent calculation of the cross-section of the wire according to the power consumption (how to make the right choice of wires, you will learn from this material) is a guarantee that the power supply will function correctly and efficiently.

Materials for the manufacture of wires

Typically, the installation of wiring in a private house or apartment is done using three-wire wires. And each vein - a separate insulation, they all have different colors - brown, blue, yellow-green (standard). The vein is the part of the wire through which the current flows. It can be either single-wire or multiwire. In some brands of wire, a cotton braid over the veins is used. Materials for wire cores:

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

Sometimes you can find a combination, for example, a copper wire stranded with several steel conductors. But such were used for field telephone communication - a signal was transmitted over the copper, and steel was used for the most part to mount the supports. Therefore, in this article about such wires, the conversation will not go. For apartments and private houses, the copper wire is ideal. It is durable, reliable, the characteristics are much higher than that of cheap aluminum. Of course, the price of a copper wire bites, but worth mentioning is that its service life (guaranteed) is 50 years.

Wire grades

For the installation of electrical wiring is best to use two brands of wires - VVGng and VVG. The first has the ending "-ng", which indicates that the insulation is not lit. It is used to conduct electrical wiring inside buildings and buildings, as well as in the ground, in the open air. Stable operation in the temperature range -50 ... +50. Guaranteed service life is at least 30 years. The cable can be with two, three or four wires, the cross section of each - in the range of 1.5 ... 35 square meters. Mm. Pay attention also to the fact that it is necessary to calculate the cross-section of the wire according to the power consumption and length (in the case of an air long line).

Carefully look at the fact that before the name of the wire there was no letter "A" (for example, AVVG). This indicates that the veins are made of aluminum inside. There are also foreign analogues - the NYM cable, which has a round shape, corresponds to the standards adopted in Germany (VDE0250). Copper conductors, insulation is not subject to combustion. The round form of the wire is much more convenient if it is necessary to carry out the installation through the wall. But to conduct wiring inside the premises is more convenient flat domestic.

Wires made of aluminum

They have a small weight, and most importantly, low cost. Therefore, useful for those cases where you need to lay long lines through the air. If all work is done correctly and correctly, you will get an ideal air line, since aluminum has one huge advantage - it is not subject to oxidation (unlike copper). But often the wiring from aluminum was used in homes (usually in old ones). Earlier it was easier to get a wire, and it cost a penny. It should be noted that the calculation of the cross-section of the wire according to the power consumption (the features of this process are known to every electrician) is the main stage in the creation of the project of electricity supply of the house. But you need to pay attention to one feature - the cross section of the aluminum wire should be greater than the copper wire to withstand the same load.

Table for calculating the cross section for power

It should also be mentioned that the maximum permissible current load on aluminum wires is much less than for copper wires. The table below will help you calculate the cross section of the conductors of the aluminum wiring.

Cross-section of wires depending on the type of wiring

There are two types of electrical wiring in homes - open and closed. As you understand, you need to take into account this nuance in making calculations. Hidden is installed inside the floors, as well as in grooves and channels, in pipes, etc. Closed wiring has higher requirements, since it has less ability to cool. And any wire with prolonged exposure to a large load heats up very much. Therefore, in case when you are calculating the cross-section of the wire according to the power consumption, the influence on heating must be taken into account. It is also necessary to take into account the following parameters:

1. Continuous current load.
2. Loss of voltage.

As the length of the wire increases, the voltage decreases. Therefore, in order to reduce the voltage loss, it is necessary to increase the cross-section of the wires of the wire. If we are talking about a small house or even a room, the value of losses is extremely low, they can be neglected. But if a long line is calculated, it does not go away. After all, the calculation of the cross-section of the wire according to the power consumption (the influence of length is very large) depends on such a parameter as the length of the line.

Power Wire Calculation

So, you need to know the following characteristics:

1. The material of which the cores of the cable consist.
2. The maximum power consumption.
3. Supply voltage.

Pay attention to the fact that when any current flows, the temperature increases and some heat is released. And the amount of heat is proportional to all the power that is dissipated on the piece of electrical wiring. If you choose the wrong cross section, then excessive heating will occur, and the result may be deplorable - ignition of the wiring and fire. Therefore, it is worthwhile to make an accurate calculation of the wire cross-section for the power consumption. Risk factors are too large, and there are many.

Optimal parameters

Optimal sections:

1. For routing outlets - 2.5 square meters. Mm.
2. Lighting group - 1.5 square meters. Mm.
3. Electrical appliances of high power (electric stove) - 4-6 square meters. Mm.

In this case, pay attention to the fact that copper wires can withstand the following loads:

1. The wire is 1.5 square meters. Mm - up to 4,1 kW (current loading - 19 amperes).
2. 2.5 sq. M. Mm - up to 5.9 kW (current - up to 27 amperes).
3. 4-6 square meters. 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 the wire according to the power consumption (the definition of important characteristics and other small factors is now known to you). Based on all the above data, you will be able to independently, without recourse to the help of professionals, draw up a correct electricity plan for your house or apartment.