Content:

Before connecting the load to the network, it is important to make sure in sufficient thickness of the emerging cable. In the event of a significant exceeding the permissible power, the destruction of isolation and even the core itself is possible due to its overheating.

Before calculating the cable cross-section for power, the power of the connected electrical appliances should be calculated. In most modern apartments The main consumers are:

• Fridge 300 W.
• Washing machine 2650 W
• Computer 550 W.
• Lighting 500 W.
• Electric kettle 1150 W.
• Microwave 700 W
• TV 160 W.
• Water heater 1950 W.
• Vacuum cleaner 600 W.
• Iron 1750 W.
• Total 10310 W \u003d 10.3 kW

In total, most modern apartments consume approximately 10 kW. Depending on the time of day, this parameter can significantly decrease. However, when choosing a conductor cross section, it is important to focus on a greater amount.

It is necessary to know the following: the calculation of the cable cross section for single-phase and three-phase networks differs. But in fact, and in another case, first of all three parameters should be taken into account:

• Tok strength (I),
• Voltage (U),
• Power consumed (P).

There are also several other variables, their value varies for each specific case.

Calculation of the cross section of the wire for a single-phase network

The calculation of the cross section of the power wire is carried out using the following formula:

I \u003d (p × k and) / (u × cos (φ))

Where,

• I.- current strength;
• P. - power consumption of all electrical appliances in the amount;
• To I. - the coefficient of simultaneity, usually the standard value of 0.75 is received for calculations;
• U. - phase voltage, it is 220 (B), but may vary in the range from 210 to 240 (B);
• COS (φ) - For household single-phase appliances, this value is unchanged and equals 1.

If necessary, it is possible to quickly calculate the current to omit the COS value (φ) and even to and. The resulting value will differ in a smaller side (by 15%) in the case of the application of the formula of this type:

I \u003d p / u

Having found a current estimated formulaYou can safely begin the choice of the feed cable. More precisely, its cross-section area. There are special tables in which data are presented to compare the current value consumption and the cable cross section.

The data differ greatly for conductors made from different metals. To date, for apartment wiring is usually used only hard copper cableAluminum practically does not apply. Although in many old houses, all lines are laid with aluminum.

The cross section of the copper cable is selected according to the following parameters:

Calculation of the cross section of the wire in the apartment - Table

It often happens that as a result of calculations, the current is obtained between the two values \u200b\u200bpresented in the table. In this case, it is necessary to use the nearest greater value. If, as a result of calculations, the current value in the single-core wire is 25 (a), it is necessary to select a cross section of 2.5 mm 2 or more.

Calculation of cable cross section for three-phase network

To calculate the cross section of the feed cable used in the three-phase network, you must use the following formula:

I \u003d p / (√3 × u × cos (φ))

Where,

• I. - The strength of the current on which the cable cross section will be selected;
• U. - phase voltage, 220 (B);
• Cos φ. - phase shift angle;
• P. - indicator of the total power of all electrical appliances.

Cos φ. This formula is very important. Since directly affects current current. For various equipment, it is different, most often with this parameter can be found in the technical accompanying documentation, or it is indicated on the housing.

The total power of consumers is very simple: all power is folded, the value obtained is used for calculations.

A distinctive feature of choosing a cable cross-section for use in a three-phase network is that a thinner vein can withstand a larger load. Selected needless section According to a typical table.

Cable Selection for Three-phase Network - Table

Calculation of the cross section of the wire in power in the three-phase network is performed using this value as √3 . This value is necessary to simplify external view Formulas.

U linear \u003d √3 × u phase

Thus, if necessary, it is possible to replace the product of the root and phase voltage to voltage linear. This value is 380 (B) (U linear \u003d 380 V).

When choosing a cable cross section, both for a three-phase network and for single-phase, must be considered permissible long-term current . This parameter indicates current strength (measured in amperes), which can withstand the conductor during an unlimited amount of time. It is determined by special tables, they are in PUE. For aluminum and copper conductors, data differ significantly.

Permissible current duration - table

When the table is exceeded in the table, the conductor begins to heat up. The heating temperature is inversely proportional to the current strength.

The cable cross section on a slice is standardized in all countries. This applies to the states of the CIS and Europe. Regulates this question in our country, document "Rules of electrical installations", which is called PUE. The calculation of the cable cross section is selected using special tables. Of course, many calculate the necessary parameters of the conductor "on the eye", but this is not entirely correct. For each apartment, this indicator may be different. This is due to the number of electrical consumers and their power. Without competent calculation, a lot of unpleasant situations may occur, costly repairs both wiring and apartments.

Cable device

To determine the cable cross section in power, its principle and device should be understood. It can be compared, for example, with a water or gas pipeline. In the same way as in these communications, a stream flows on the electrical conductory. Its power limits the conductor cross section.

The cable cross section using power indicator can be performed incorrectly in two cases:

1. The current channel will be too narrow. This will lead to an increase in current density and, therefore, to overheating isolation. This condition of the conductor will be characterized by the presence of weak places where leakage is possible. Such a state of the channel may cause a fire.
2. Too wide speaking livers. This, of course, is not the worst option. Examination of the electric flux will allow more functionally and durable to use the conductor. However, the cost of cable increases with increasing section.

The first option is a danger to life, health and property. The second method is safe, but the materials will be quite expensive when buying.

Easy way

The calculation of the cable cross section is based on the well-known law developed by OMOM. It reports that the strength of current flowing is multiplied by voltage will be equal to power. The voltage in everyday life is considered a constant value. In a single-phase network, it is equal to 220 V. Therefore, to determine the cross section of the cable in the current indicator, and only two variables remain.

Next, current values \u200b\u200bare calculated and the estimated load. Moreover, the size of the cable at its power can be selected by the PUE table. This indicator is calculated for the wire suitable for outlets. Traditionally, the lighting lines are paved with a cross section of 1.5 mm 2.

However, it happens that such devices such as a hairdryer, microwave, electric kettle are connected to the socket group, and so on. It is necessary to distribute the load and correctly calculate the cable cross section in terms of power corrected diameter and load.

If it is not possible to break out the sockets, then many electricians recommend immediately install a cable with copper living to 6 mm 2.

Section area and diameter

Calculation of the cable cross section for power, diameter and load are not equivalent concepts. The first indicator is calculated in mm 2, and the second is simply in mm. You can choose the power and permissible strength of the table on the table both by cross section of the cable and in its diameter.

If the table takes into account only the size of the section of the cross section in mm 2, and there is only data on the diameter of the cable, the missing indicator can be found according to the following formula:

S \u003d 3,14d 2/4 \u003d 0,785d 2,

where: S is the cross section of the wire, and D is the diameter.

If the wire in the cross section is not round, but rectangular, its cross-sectional area is calculated to multiply the length of the width (just like the area of \u200b\u200bthe rectangle).

Load-based calculation

Calculation of the cable wire is easiest to perform by summing the capacities of all units that will be connected to the line. This will require a certain sequence of actions.

First, it is determined which electrical devices will be used in the dwelling, which of them will probably be functioning simultaneously. Next, it is necessary to look into the passports of each of these aggregates. It will be necessary to calculate the amount of power of those electrical consumers that should work simultaneously.

Then the indicator obtained as a result of the calculations carried out is rounded into the biggest. This will ensure a safe power supply of electrical wiring. The cross section of the wire or cable is calculated later using PUE tables.

In the same way, you can sum up the current strength, which is indicated in the technical equipment of electrical equipment. The rounding and search on the power calculation table is performed.

Power table, current and sections of copper wires

According to Pue, in residential buildings it is necessary to use only copper veins to arrange wiring. Nutrition of some electrical equipment, which relates to engineering types of receivers, can be connected to a network of aluminum veins with a cross section of at least 2.5 mm 2.

Power table, current and cross section of aluminum wires

Specialist will also be able to make corrective coefficients for the location of the wire, temperature ambientFor cable in the ground, etc. The table of calculating the power of the cable, cross-section or strength of the current touches the conductors in plastic or rubber insulation. These include such common stamps such as GDP, PVS, PPV, WFP, AVVG, VG, ADPV, etc. Unison or with a paper screen, cables should be calculated according to the table related to them.

Length and section

The calculation of the cable cross section is simply necessary to use to determine its length. These data are important when creating long-length extension cords. The obtained accurate values \u200b\u200bare necessary to increase by 10-15 cm. This stock is necessary for switching using soldering, welding or crimping.

The construction calculates the cable cross section in terms of power and length at the design of the wiring. This is very important, especially for those communications that will be subject to significant or additional loads.

In everyday life calculation of the wire length is made according to the following formula:

I \u003d p / u * cosφ, where:

• P - power (W);
• I - current (a);
• U - voltage (B);
• cosφ is a coefficient that is equal to 1.

The cable cross section should be found in the table. The formula will help determine the correct length of the wire.

Cone density

The strength of the current varies in the range of 6-10 A, which was derived by the experimental way. This value is calculated for the current flowing in 1 mm 2 copper veins.

Such an assertion means that the calculation of the cable cross-section for power and current takes as the basis of the copper cable with a section of 1 mm 2, according to which without refining and overheating can flow from 6 to 10 A to the waist electrical appliances.

According to the PUE Code, the stock of 40% is given for each wire to the overall overheating for the shell. If the value of 6 A characterizes the operation of the presented conductor is an infinitely long term without restrictions on time, then the indicator 10 A is suitable for short-term flow flow through the core.

If 1 mm 2 is currently flowing at a copper conductor 12 A, it will be closely in such a dwelling. This will lead to an increase in current density. There will begin to heat up and will melt isolation.

Therefore, such calculations are required when a cable cross section is selected for each type of wiring.

After reviewing the techniques that allow you to calculate the cable cross-section for power and strength, you can pave or repair the old wiring, which will serve for a long time and will be fully safe for people living in the house. A lot of fairly simple, but effective ways will help accurately decide on the necessary size of the cross section for the power grid.

As you know, there are different sections, material and with different quantities lived. Which one should choose not to overpay, and at the same time ensure the safe stable operation of all electrical appliances in the house? To do this, make a cable calculation. The calculation of the section is carried out, knowing the power of devices that feed on the network, and the current that will pass through the cable. You also need to know several other posting parameters.

Fundamental rules

When laying power grid in residential buildings, garages, apartments most often use cable with rubber or PVC insulation, designed for voltage of no more than 1 kV. There are brands that can be used in the open air, indoors, in the walls (strokers) and pipes. Usually this cable VVG. or AVVG S. different area Sections and quantities lived.
The PVA wires and the ShVVP cords are also used to connect electrical appliances.

After the calculation, the maximum allowable section of the cross section from a series of cable brands is selected.

The basic guidelines for the choice of sections are in the rules of the electrical installation device (PUE). The 6th and 7th editions were released, in which it is described in detail how to lay cables and wires, to establish protection, distributing devices and other important points.

For violation of the rules, administrative fines are provided. But the most important thing is that the violation of the rules can lead to the failure of the electrical appliances, wiring and serious fires. The damage from the fire is measured sometimes not the sum of money, but by human victims.

The importance of the right segment

Why is the calculation of the cable cross section so important? To answer, you need to remember the school lessons of physics.

The current proceeds along the wires and heats them. The stronger the power, the greater the heating. The active power of the current is calculated by the formula:

P \u003d U. I. cos φ \u003d ² * r

R. - Active resistance.

As can be seen, power depends on the strength of the current and resistance. The more resistance, the more heat allocates, that is, the stronger the wires are heated. Similar to current. What he is more, the more heated the conductor.

Resistance in turn depends on the material of the conductor, its length and cross-sectional area.

R \u003d ρ * L / S

ρ - resistivity;

l. - the length of the conductor;

S.- Cross-section area.

It can be seen that less square, the more resistance. And the more resistance, ther the conductor is stronger than it.

If you buy the wire and measure it with diameter, do not forget that the area is calculated by the formula:

S \u003d π * d² / 4

d. - diameter.

You should also not forget the specific resistance. It depends on the material from which the wires are made. The resistivity of aluminum is greater than copper. So, with the same area, aluminum will be heighted harder. It immediately becomes clear why aluminum wires are recommended to take a larger cross section than copper.

To do not go into the long calculation of the cable cross section, the rules of sections of the wire section were developed in tables.

Calculation of the cross section of the power and current

The calculation of the cross section of the wire depends on the total power consumed by electrical appliances in the apartment. It can be calculated individually, or use the average characteristics.

The accuracy of calculations constitute the structural scheme, which depicts devices. You can learn the power of each from the instructions or read on the label. The greatest power in electric ovens, boilers, air conditioners. The total digit should turn out in the range of approximately 5-15 kW.

Knowing power, according to the formula determines the rated current strength:

I \u003d (p K) / (ucos φ)

P. - Power in watts

U.\u003d 220 Volt.

K.\u003d 0.75 - the coefficient of simultaneous inclusion;

cos φ \u003d 1 for household electrical appliances;

If the network is three-phase, then use another formula:

I \u003d p / (u √3 cos φ)

U.\u003d 380 VOLT.

Calculating the current, you need to use the tables that are presented in PUE, and determine the cross section of the wire. The tables specify the allowable long-term current for copper and aluminum wires with isolation of various types. Rounding is always produced in the biggest, so that there is a stock.

You can also refer to the tables in which the section is recommended to determine only in power.

Special calculators are developed, which determine the section, knowing the power consumption, network phase, and length cable line. Attention should be paid to the laying conditions (in the pipe or outdoors).

Influence of wiring length on cable selection

If the cable is very long, then there are additional limitations on the sequence of section, since there are voltage losses on the extended portion, which in turn leads to additional heating. To calculate the loss of voltage use the concept of "moment of load". It is determined as a product of power in kilowatts for length in meters. Next, look at the loss value in the tables. For example, if the power consumption is 2 kW, and the cable length is 40 m, then the moment is equal to 80 kW * m. For a copper cable with a cross section of 2.5 mm square. This means that voltage losses are 2-3%.

If the losses will exceed 5%, then it is necessary to take a segment with a margin, more recommended for use at a given current.

Estimated tables are provided separately for a single-phase and three-phase network. For a three-phase moment of load increases, since the load capacity is distributed over the three phases. Consequently, losses are reduced, and the effect of length decreases.

Voltage losses are important for low-voltage devices, in particular, gas-discharge lamps. If the supply voltage is 12 V, then with a loss of 3% for the network 220 to the fall will be much noticeable, and for a low-voltage lamp it will decrease almost twice. Therefore, it is important to place start-adjusting devices as close as possible to such lamps.

The calculation of the loss of voltage is performed as follows:

ΔU \u003d (P ∙ R0 + Q ∙ x0) ∙ L / UON

P. - active power, W.

Q. - reactive power, W.

r0 - Active line resistance, OM / m.

x0. - reactive line resistance, OM / m.

UAN - Rated voltage, V. (It is indicated in the characteristics of electrical appliances).

L. - Length line, m.

Well, if easier for living conditions:

R. - cable resistance, calculated according to the well-known formula R \u003d ρ * L / S;

I. - the current is found from the Ohm law;

Suppose we happened that I.\u003d 4000 W / 220 IN\u003d 18.2 A.

Resistance to one copper wire vein with a length of 20 m and an area of \u200b\u200b1.5 mm square. amounted to R.\u003d 0.23 ohms. The total resistance of the two veins is 0.46 ohms.

Then ΔU.\u003d 18.2 * 0.46 \u003d 8.37 V

In percentage ratio

8,37*100/220=3,8%

On long lines from overload and short circuits are installed with thermal and electromagnetic releases.

For the correct and secure installation of cables for wiring, it is necessary to preliminarily calculate the intended power consumption. Failure to comply with the sembling sequence of the cable used for wiring can lead to a laying of isolation and fire.

Calculation of the cable cross section for a specific electrical wiring system can be divided into several stages:

1. breakdown of electricity consumers by groups;
2. determination of the maximum current for each segment;
3. selecting a cable cross section.

All consuming electrical appliances should be divided into several groups so that the total power of consumption by one group was not above 2.5-3 kW. This will allow you to choose a copper cable with a cross section of no more than 2.5 square meters. mm. Power of some basic household appliances shown in Table 1.

Table 1. Power value of the main household appliances.

Consumers combined in one group must be geographically about one place, as they are connected to one cable. If the entire connected object is powered by a single-phase network, the number of groups and the distribution of consumers do not play a significant role.

Then the percentage of discrepancies can be calculated by the formula \u003d 100% - (PMIN / PMAX * 100%)where Pmax is the maximum total power per phase, the PMIN is the minimum total power per phase. The less the percentage of power discrepancies, the better.

Calculation of the maximum current for each group of consumers

After the power consumption was found for each group, you can calculate the maximum current. The demand ratio (COP) is better to take everywhere 1, since it does not exclude all the elements of the same group at the same time (for example, you can also include all household appliances related to one group of consumers). Then the formulas for a single-phase and three-phase network will look at:

IISCH \u003d PRAC / (URAN * COSφ)
For a single-phase network, in this case, the voltage in the network is 220 V,

ISURCH \u003d PRAC / (√3 * Us * cosφ)
For a three-phase network, a voltage in the network 380 V.

When installing wiring in recent decades, a special popularity has been specially popularity. This is explained by the whole set of properties that the corrugated pipe has, but at the same time, when working with it, it is necessary to follow certain rules.

It is often possible to meet in theory, and in practice terms the connection of a triangle and a star, the voltage phase and linear - to understand their differences will help interesting.

The cosine value for household appliances and illumination of incandescent lamps is taken equal to 1, for LED lighting - 0.95, for luminescent lighting - 0.92. For the group there is a mid-industrial cosine. Its value depends on which cosine at the device that consumes the highest power in this group. Thus, knowing the currents on all sections of the wiring, you can proceed to the sequence of the cross section of the wires and cables.

Selection of cable cross-section

For known values Calculated maximum current can be proceeded with the selection of cables. This can be done in two ways, but the easiest way to choose the desired section Cable on tabular data. The parameters for selecting a copper and aluminum cable are shown in the table below.

Table 2. Data to select a cable cross section with copper and aluminum cable.

When planning wiring, it is preferable to choose cables from one material. The connection of copper and aluminum wires by the usual twist is prohibited by the rules of fire safety, since when the temperature fluctuations, these metals are expanding differently, which leads to the formation of gaps between contacts and heat release. If there is a need to connect cables from different materialsIt is best to take advantage of specially intended for this terminals.

Video with cable cross sectional formulas

Competent selection of the cable for restoring or laying wiring ensures impeccable system operation. The devices will receive power in a full amount. Overheating of isolation with subsequent devastating consequences will not happen. The reasonable calculation of the cross-section of the wire in power will save and from threats of ignition, and from the extra costs of the purchase of the cheap wire. Let's figure it out in the calculation algorithm.

Simplified cable can be compared with pipeline transporting gas or water. In the same way, the stream moves, the parameters of which are limited to the size of this current channel channel. The consequence of the incorrect selection of its cross section is the two common erroneous options:

• Too narrow current channel, due to which the current density is rated. The increase in current density entails an insulation overheating, then its melting. As a result, the melting will at least appear "weak" places for regular leaks, to the maximum fire.
• Needlessly lived, that, in essence, quite well. Moreover, the presence of space for the transportation of the electric flow is very positively reflected in the functionality and operational timing of the wiring. However, the owner's pocket will make it easier for the amount by half the money that needs.

The first of the erroneous options is a frank danger, at best will entail an increase in payment for electricity. The second option is not dangerous, but extremely undesirable.

"Protane" calculation paths

All existing calculated ways are based on the law-derived by Omom, according to which the current is multiplied by the voltage equals the power. Domestic voltage - a constant value equal to a single-phase network standard 220V means, only two variables remain in the legendary formula: it is a power current. You can "dance" in the calculations and you need from one of them. Through the calculated values \u200b\u200bof the current and the estimated load in the PUE tables, we find the required section of the cross section.

Note that the cable cross section is calculated for power lines, i.e. For wires to sockets. A priori lighting lines are paved with a cable with a traditional size of a cross-sectional area of \u200b\u200b1.5 mm².

If there is no powerful disco-ferrous or chandelier in the placed room, which requires power to 3,3к and more, then increasing the area of \u200b\u200bcross-section of the lighting cable does not make sense. But the rosette question is a purely individual, because Connect to one line can such unequal tandems, as a hairdryer with a water heater or an electric kettle with a microwave.

Those who plan to load the power line of electrical hobs, boiler, washing machine and similar "voracious" technique, it is desirable to distribute the entire load on several socket groups.

If the technical ability to break the load on the groups is not, beach electricians Recommend without clauses to lay a cable with a copper residential cross section of 4-6 mm². Why with copper current core? Because the strict Code of the PUE laying the cable with an aluminum "stuffing" in the housing and in the actively used household premises is prohibited. The resistance of the electrotechnical copper is much smaller, it passes more and does not heat up as aluminum. Aluminum wires are used in the device of external air networks, in some places they still remain in old houses.

Note! The cross-section area and the cable veins diameter are different things. The first is denoted in square mm, the second is simply in mm. The main thing is not to confuse!

To search for table values \u200b\u200bof power and permissible current, you can use both indicators. If the table indicates the size of the cross section in mm², and we only know the diameter in mm, the area needs to be found according to the following formula:

Calculation of the size of the load section

The simplest method of selection of the cable with the desired size is the calculation of the cross-section of the wire in the total power of all connected to the unit of the aggregates.

The algorithm of settlement actions is as follows:

• to begin with, we will define the aggregates that allegedly be used by us at the same time. For example, during the work of the boiler, we suddenly want to turn on the coffee grinder, hairdryer and washing;
• then according to the data of the data or according to approximate information from the table below, we tritely summarize the capacity at the same time working according to our plans of household aggregates;
• suppose that in the amount we had 9.2 kW, but there is no particular value in the PUE tables. So you have to round in a safe majority - i.e. Take the nearest value with some power excess. It will be 10.1 kW and the corresponding value of the section 6 mm².

All rounding "We guide" towards the increase. In principle, it is possible to summarize the strength of the current specified in the technical supports. Calculations and current roundings are produced in a similar way.

How to calculate the current section?

Table values \u200b\u200bcan not take into account individual features Network devices and operation. The specificity of the tables are average. They do not contain the parameters of the maximum permissible for a specific cable of currents, and they differ from products with different stamps. Very superficially affected the tables of the gasket. Mattering masters rejecting the easy way to search tables, it is better to use the method of calculating the secting of the current wire. More precisely on its density.

Permissible and working current density

Let's start with the development of Azov: We remember in practice the removed interval 6 - 10. These are the values \u200b\u200bobtained by electricians with many years of "experienced way". At these limits, the strength of the current flowing in 1 mm² of copper veins is varies. Those. The cable with a copper core section of 1 mm² without overheating and the discharge of isolation provides the possibility of current from 6 to 10 and quietly reach the expectant of its consumer aggregate. We will understand where it came from and what the designated interval fork means.

According to the Code of Electrical Laws of PUE 40%, the cable is assigned to the overall overheating for its shell, it means:

• 6 A, distributed on 1 mm² of current-handed cores, are a normal current current density. In these conditions, the conductor can work infinitely for a long time without any time limit;
• 10 A, distributed on 1 mm² copper core, leak through the conductor can be shortly. For example, when the device is turned on.

The stream of energy is 12 and in the copper millimeter channel will be initially "closely". From the tightness and attachment of electrons will increase the current density. Following the temperature of the copper component increases, which is consistently reflected in the state of the insulating shell.

Please note that for cable with an aluminum current-handed residential current density displays an interval of 4 - 6 amps, per 1 mm² conductor.

It turned out that the limiting value of the current density for the conductor from the electrical copper 10 A to the cross-sectional area of \u200b\u200b1 mm², and the normal 6 A. is therefore:

• a cable with a residential cross section of 2.5 mm² will be able to transport current at 25 and only a few tenth seconds during the inclusion of equipment;
• he can be infinite for a long time to transmit a current in 15a.

The above current density values \u200b\u200bare valid for open wiring. If the cable is paved in the wall, in the metal sleeve or, the specified current density value must be multiplied by the correction coefficient of 0.8. Remember another subtlety in organizing an open type of wiring. For reasons of mechanical strength, the cable with a cross section is less than 4 mm² in open circuits are not used.

Study of the calculation scheme

Supervised computing will not be again, the calculation of the wire for the upcoming load is extremely simple.

• We will first find the maximum permissible load. To do this, we summarize the power of the devices that we assume simultaneously connect to the line. Mix, for example, power washing machine 2000 W, 1000 W hair dryer and an arbitrarily incomplete 1500 W heater. We received 4500 W or 4.5 kW.
• Then we divide our result on the standard value of the voltage of the household network 220 V. We received 20.45 ... and, rounded to an integer, as it should be on the most side.
• Next, enter the correction coefficient if it has a need. The value with the coefficient will be 16.8, rounded 17 A, without coefficient 21 A.
• We remember that the operating parameters of power were calculated, and you need to take into account the maximum allowable value. For this, the current strength calculated by the current is multiplied by 1.4, because the correction for thermal exposure is 40%. Received: 23.8 A and 29.4 A, accordingly.
• So, in our example, a cable with a cross section of more than 3 mm² will be required for the safe operation of open wiring, and for a hidden version of 2.5 mm².

It will not forget that, due to diverse circumstances, we sometimes include more units at the same time than calculated. That there are still light bulbs and other devices, slightly consuming energy. Stopping some reserve section for the event of an increase in the park household appliances And with the calculations will go for an important purchase.

Video guide for accurate calculations

Which cable is better to buy?

Following the strict recommendations of the PUE, to buy for the arrangement of personal property will cable products With "Little Groups" NYM and VG in marking. It is they who do not cause complaints and pick-up from the side of electricians and firefighters. NYM option is an analogue of domestic products VVG.

Best of all, if the domestic cable will accompany the NG index, this means that the wiring will be fire-resistant. If it is supposed to lay a line behind the partition, between lags or above suspended ceiling, buy products with low smoke. They will have an LS index.

This is so simple, the cross section of the conductive cable veins is calculated. Information about the principles of computing will help rationally pick up this important element Power network. The necessary and sufficient size of the current-carrying core will provide food with homework and the wiring is not caused.