Calculation of wire cross-section for power consumption. Features of the calculation

This article will explain howto calculate the wire cross-section for power consumption independently. You need to know this not only when installing electrical wiring in the house, but also when working in cars, for example. If the cross section of the wire is insufficient, it will start to heat up very much, which will lead to a significant loss of security level. Considering all the recommendations that will be presented 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 contact the experts in this field. Moreover, it should be noted that the calculation of the wire cross-section according to the power consumption (12V and 220V) is performed similarly.

Calculation of the length of the wiring

For any type of electronic system the most importantthe condition for stable and trouble-free operation is a competent 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. Измерение расстояния от щитков до розеток, switches according to the wiring diagram. Moreover, this can be done with a ruler on a previously prepared plan of electrical wiring - sufficiently multiplied values ​​of the lengths by scale.
2. And the second, more accurate way is to arm yourself.ruler and walk through all the rooms, taking measurements. Moreover, it should be borne in mind that the wires must somehow be connected, so there must always be a stock - at least one or two centimeters from each edge of the wiring.

Now you can proceed to the next step.

Calculate the load on the wiring

To calculate the total load, you need to addall the minimum power consumers around the house. Suppose you spend the calculation for the kitchen, it has lamps, a microwave oven, an electric kettle and a stove, a dishwasher, and so on. All capacities must be summed up (look at the power consumption on the back covers, but you will have to calculate the current for this parameter yourself). After multiply by the correction factor 0.75. It is also called the coefficient of simultaneity. Its essence is clear from the name itself. This figure, which will turn out as a result of calculations, you will need in the future to carry out calculations of the parameters of wires. Please note that the entire power supply system must be safe, reliable and durable. These are the basic requirements that must be considered when calculating the cross-section of the wire on the power consumption of 12V and 220V.

Electrical consumption current

Now how to calculate the consumedcurrent electrical device. You can do it in your mind, or you can do it on a calculator. See the instructions for the device, what is the value of power consumption from him. Needless to say, in a household electrical outlet alternating current flows with a voltage of 220 volts. Therefore, using a simple formula (power consumption divided by the supply voltage), you can calculate the current. For example, an electric kettle has a power of 1000 watts. So, if you divide 1000 by 220, we get a value approximately equal to 4.55 amperes. It is very easy to calculate the wire cross section for power consumption. How to implement this is described in the article. In operation mode, the kettle consumes 4.55 amperes from the mains (for protection, it is necessary to install a circuit breaker with a higher rating). But note that this is not always the exact meaning. For example, if there is an engine in the design of an electrical device, you can increase the value obtained by about 25% - the current consumption of the motor in the starting mode is much greater than during idle operation.

Recommendations of the EMP

Но можно воспользоваться сводом правил и standards. There is such a document as the Rules for electrical installations, it regulates all the rules of wiring, not only in private possessions, but also in factories, etc. According to these rules, the standard wiring is the ability to withstand a load of 25 amps for a long time. Therefore, in the apartments all wiring should be done only with the use of copper wire, its cross section is not less than 5 square meters. mm Each vein should have a cross section of more than 2.5 square meters. mm The conductor diameter should be 1.8 mm.

Чтобы вся электропроводка работала максимально safely, on input installation of the automatic switch is made. He will protect the apartment from short circuits. Also recently, most homeowners have installed protective cutout devices that act instantly on resistance changes in the circuit. In other words, if you accidentally touch bare wires under voltage, they will immediately be de-energized and you will not get hit. Circuit breakers must be counted on current, and it is necessary to choose with a margin so that there is always the possibility to install any electrical appliance in the house. Competent calculation of the wire cross section for power consumption (you will learn how to make the right choice of wires from this material) is a guarantee that the power supply will function correctly and efficiently.

Materials for the manufacture of wires

As a rule, installation of electrical wiring in privatehouse or apartment do with the use of three-wire. Moreover, each core has a separate insulation, they all have different colors - brown, blue, yellow-green (standard). A vein is exactly that part of the wire through which current flows. It can be either single-wire or multi-wire. In some brands of wire used cotton sheath over lived. Materials for the manufacture of core wires:

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

Sometimes you can find combined, for example,multi-wire copper wire with several steel conductors. But these were used for the implementation of field telephony - a signal was transmitted over copper, and the steel ones were used for the most part for fastening to supports. Therefore, in this article about such wires conversation will not go. Copper wire is ideal for apartments and private houses. It is durable, reliable, the characteristics are much higher than that of cheap aluminum. Of course, the price of copper wire bites, but it is worth mentioning that its lifetime (guaranteed) is 50 years.

Wire marks

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

Carefully look in front of the titlethe wire was not the letter "A" (for example, AVVG). This suggests that inside the cores are made of aluminum. There are also foreign analogues - cable brand NYM, which has a round shape, meets the standards adopted in Germany (VDE0250). Copper veins, isolation is not subject to burning. The round shape of the wire is much more convenient if you need to mount through a wall. But for the conduct of indoor wiring is more convenient flat domestic.

Aluminum wires

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

Table for the calculation of 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 calculate the cross-section of the conductors of aluminum wiring.

Wire size depending on the type of wiring

There are two types of electrical installationwiring in homes - indoor and outdoor. As you understand, it is necessary to take into account this nuance when making calculations. Hidden is mounted inside the ceiling, as well as in the grooves and channels, pipes, etc. Closed wiring has higher requirements, as it has a lower capacity for cooling. And any wire with a long exposure to a large load heats up very much. Therefore, in the case when calculating the wire cross section for power consumption, the effect on heating must be taken into account. It is also necessary to take into account the following parameters:

1. Long current load.
2. Loss of stress.

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

Calculation of wire for power

So, you need to know the following characteristics:

1. The material that make up the cable cores.
2. Maximum power consumption.
3. Supply voltage.

Note that when leakingAny current temperature rises and a certain amount of 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 pick up the wrong section, then there will be excessive heat, and the result can be deplorable - ignition of electrical wiring and fire. Therefore it is necessary to carry out an exact calculation of the wire cross section for power consumption. Risk factors are too big, and there are many.

Optimal parameters

Optimum sections:

1. For wiring sockets - 2.5 square meters. mm
2. Lighting group - 1.5 square meters. mm
3. Electrical appliances high power (electric stove) - 4-6 square meters. mm

At the same time pay attention to the fact that copper wires can withstand the following loads:

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

Therefore, with increasing load, you will always have a fairly large reserve.

Conclusion

Now you know how to calculate the section.wires for power consumption (the definition of important characteristics and other small factors you now know). Based on all of the above data, you can independently, without resorting to the help of professionals, to draw up an electricity plan correctly for your house or apartment.