Calculation of electrical work in the apartment. How much cable do you need to supply electricity to your home or apartment?

Before installing the wiring, you need to make the correct calculation of the cable length. You can carry out the correct calculation in two ways. In the first method, you will need to rely on a ready-made scheme, which you should have prepared in advance. The second method involves calculating the length of the cable according to the total area of ​​the rooms.

Which of these ways you choose to decide only you. In this article, we have detailed how to calculate the number of cables for wiring in a private house.

  Calculation of the cable length using a circuit

Calculation of the number of cables will perform much easier if you have already compiled the finished circuit.

Here are the main points that you should have indicated on the diagram:

1. It is necessary to specify the exact number of all switches, sockets and junction boxes, which will be in the room. Also, for a more accurate calculation of the length of the cable, it is necessary to correctly indicate their height from the floor.
2. Specify not only the location of the main lighting installation, but also the place for installing additional lighting. To additional lighting include: sconces, spotlights. Before calculating the length of the cable for wiring, you need to determine the height of the ceiling. If the ceiling does not drop, then the stock should be 20 cm. If it drops by 30 cm, then the stock should be 50 centimeters.
3. When designing the circuit, be sure to specify which cable section to use. For example, a 3x1.5 mm wire is suitable for lighting. For sockets it is better to use a powerful wire 3x2.5 mm. To connect powerful devices in your home use a wire 3x4 mm.

As you can see, in order to make the correct calculation of the length of the wire, it is necessary to take into account its cross section. Then you can definitely decide how much cable you need for the apartment. With the cross section for household appliances, it is better to decide before drawing up the scheme. This is all, because it is better to connect powerful devices directly from the shield. requires compulsory calculation of the scheme.

After preparing a visual project, you will understand how much cable you need to power the house or apartment. It will be even better if you immediately make markings on the walls. To do this, you simply draw the lines and calculate the total number of each wire.

In each calculation, you should also make some adjustments. The main adjustments include:

1. You need to multiply the number of wires by 1.2. Thanks to this calculation, you will not have a situation with a shortage of wires.
2. For switches, the length margin must be at least 15 cm.
3. If you have not yet decided what type of ceiling you will have, then it is better to leave 50 cm to the reserve.
4. For work in the switchboard, the safety margin should be 50 cm.

  Calculation of the cable quantity by means of calculations

If you do not want to spend your time designing the circuit, then you can calculate the length of the cable in a simplified scheme. is open and therefore it can easily be calculated using this scheme. A simplified scheme for calculating the length of conductors allows you to save your time. Sometimes this method is used even by professional electricians. Its essence lies in the fact that you will need to calculate the amount of cable per floor space. To do this, you need to take the area of ​​your house and multiply this number by 2. This is how much cable you will need for wiring.

Here this variant of calculation is considered the most simple, but you also should not forget about additional nuances. With this, you will calculate only your length for one line. It is not possible to accurately determine the length using this circuit. In order to calculate the length of the cable was correct you will need to consider the products in a ratio of 1: 1.5. The first number is taken to light for rooms, and the second to connect the outlets.

On the Internet, you can find a large number of reviews about this scheme. Even professional electricians report that this method is not only simple, but also true. If you are not sure that your calculation is correct, then it is better to buy wires for 10 meters more. You definitely need this stock.

Which wire should I choose?   Such a question arises when it is necessary to replace the old electrical wiring or to lay a new one . Wire Selection   this is a responsible event. Given the number of electrical appliances, the correct wire selection   for a modern home is becoming very important business.

The first thing to think about is the choice of wire cross-section. The larger the cross-sectional area of ​​the wire, the greater the current through which it can pass and, correspondingly, the greater power. But this does not mean that it's best to take the thickest cable and lay it everywhere. This of course can be done, but at least it is not economical. It is much better to determine what is the power of the consumer and to select the section of the wire for it. In order to correctly choose the wire section, you can use the table below.

Table of power and section of wires

I will say at once that, usually, the maximum power supplied to the apartment does not exceed 6.6 kW. And so choosing a wire with a cross section of more than 2.5 mm 2 is not advisable.

Another question that arises from this table: is it necessary to use a wire with a cross section of 2.5mm2 everywhere. It is certainly permissible, but it is not very economical. Cheaper and more accurate, for example, for lighting use a wire with a smaller cross section. Determine the required cross-section is simple enough, for this it is sufficient to sum the power of the consumers of the line that you are making.

Now consider this question, which wire is better copper or aluminum? Not giving in details and the guests, I will say that it is better to use a copper wire and preferably a twisted wire to lay electrical wiring in the room. First, the copper wire withstands more current.

And secondly, with copper twisted wire   easier to work with, it bends well and does not break. With a cross-section and a material of wires have understood. Now consider this question: how many wires there should be. If there is a ground connection in the house or apartment, a three-core cable must be used. If the grounding is not provided, then it is possible to use two wires. Also, three wires need to be installed for installation double circuit breaker. In all other cases, two cores are perfectly suitable.

And one more question: whether it is possible to connect copper and aluminum wires?

Answer:   directly it is impossible. For this, there are special connectors.

Correctly calculate the wiring

Regardless of where you lay the wiring to this repair should be approached with all responsibility. Correctly designed wiring in the apartment is a security pledge! So how to calculate the wiring.

Given that in the past 20 years the number of electrical appliances in any apartment has increased many times the old wiring simply can not cope with so many consumers. What to avoid these problems should be correct calculation of electrical wiring.

The main stage of the calculation is to calculate the power of consumers in order to prevent overloading of the line. Consider the calculation of electrical wiring in the apartment on the example of a one-room apartment.

We will proceed from the fact that we will be laying the wiring in a hidden way, with a copper wire of 2.5 mm2.

Now we will consider what electrical appliances we can have in the apartment and their capacity: electric kettle - 2kW, microwave oven - 0.7kW, air conditioning - 2kW, washing machine - 1kW, electric water heater - 2kW, iron - 2kW, oil heater   - 2kW, other small electrical appliances and lighting from 0.5 and more.

If you combine the power of all devices, it will be clear that if you do not include all of them at the same time, then the permissible value is exceeded. Therefore, they can not be included in one line. The solution is simple to make several parallel lines (channels) of electrical wiring in the apartment. One line will go to the kitchen, the other into the room, etc. If the number of electrical appliances is greater then more lines may be required. Accordingly, each line will go to its circuit breaker in the switchboard. However, the power of the input cable must be considered.

How to approximate the calculation of electrical wiring in the apartment, we decided. Now you can calculate how much and what kind of wire you need.

How to properly install electrical wiring?

Wiring in the apartment is carried out in two ways. The first way: it is an external electrical wiring. The second way: it's a hidden wiring. Typically, in apartments, the gasket is carried out by a hidden method.

The first thing to start laying electrical wiring, this determines the location of future outlets and switches. After that, the walls are made of stitches, these are depressions in the hay, where wires are later placed. According to the rules, the wires must first be placed in cable channels.

In the junction of individual wires, special distribution boxes are installed. To ensure that in the future there were no problems with finding the place of passage of wires, they are located strictly horizontally and vertically at a distance of 20 - 30 cm from the wall, floor, ceiling. The location of the wires diagonally is not desirable.

Calculation and selection of electric network elements

Building a house requires a lot of calculations. Before commencing work on the arrangement of any communication in the house, careful calculations must be made and electric project   . Performing preliminary calculations allows you to choose the right one necessary equipment   and materials.
Correctly performed calculations allow you to make competent wiring that will function without failures.

Wiring in a private house

Cabling in individual households is best done before the finish. Before the installation of electrical wiring, you should consider where to locate household appliances, to calculate what their total capacity is. To calculate the total capacity, the power consumption of the installed electrical appliances can be found on the housing of each device or in accompanying documents.
After calculating the total power of all electrical appliances, calculate electric currents, required for consumption by these devices. The meter of the necessary number of wires, find out with the help of a tape measure. When taking measurements, all angles and niches that are in the way of the future layout of the wires should be taken into account. All household appliances that will be connected to the mains are recalculated. The total number of wiring increases by 15%, this is done to obtain a standard supply of wires.
To calculate the required cable cross-section, the electricity is calculated. Carrying out these calculations requires the collection of some input data:
how to mount the wiring;
from what material the wiring will be made;
data on the power consumption of devices connected to the mains.
The installation of electricity is carried out by an open and closed method. An open method is laying a cable over the surface of walls, a closed method is laying wires in pre-made grooves in the plaster. After laying the cable, they are covered with plaster.
Materials for production electrical wires   - aluminum and copper. Aluminum wire is quite brittle and breaks fast with several twists. The copper wire has proven itself well, it is solid (single) and sinewy, consisting of several thin veins.
Connecting electrical appliances to the network is carried out with the help of wires. A household appliance of higher power requires a larger cross-section for connecting to the network. The more wires are connected to the cable through the transfer case, the greater the cross-section of this wire. After choosing a method wiring installation   and the required cable cross-section, the design of circuit breakers is selected.

Wiring diagram and components

The calculation of electricity in the house makes it possible to prepare a wiring diagram that will facilitate its installation, and in the future it is necessary for carrying out repair work, so as not to damage the wiring. For small houses, you can perform a general wiring diagram, and in larger houses it is better to do it by floor or separately for each room.
The electrical network consists of the following elements: electrical panels, meters, wires or cables, switches, transfer boxes, circuit breakers, sockets, insulating material and connecting wires.
In electric boards, devices and components of the network are mounted, special electrical equipment. To calculate the consumed electricity, single-phase devices are installed in the network, which measure the current with the parameters of 220V / 50Hz and three-phase meters that measure current with the indices of 380V / 50Hz. The circuit breakers are designed to open the circuit when it is overloaded and shorted. Material for their production is fireproof plastic. In a private house, one-, two- and three-core copper cables are used.
Cables from different metals are connected by special connecting blocks. Multi-strand copper cables can be connected together by soldering. The insulation of the joints is carried out with an insulating tape made of polyvinylchloride or impregnated with a special impregnation of cotton tape. Heat shrinkage is gaining popularity. This insulation in the form of a tube, which when heated, compresses and seals the connection completely, without the possibility of disconnecting it.

Wiring is an important element of home improvement. Depending on the material used and the quality of installation, your safety and the safety of your family depend. It is very important to correctly select and calculate the cable cross section for wiring.

  What material should I use for wiring?

When building a new house or carrying out major repairs in it, it is worthwhile to think about the quality of the electrical wiring installed there. According to the regulatory documents of the electrical wiring hidden gasket   should not exceed 40 years before major replacement.

For the installation of electrical wiring used aluminum or copper wires. Aluminum is cheaper, copper is more reliable. So what to choose? With the correct calculation of the wire cross section, it does not really matter which wire you use. Aluminum wire is lighter, but, unfortunately, aluminum wires withstand 7-9 fold-folds, then they can crack or break off. With copper it is easier to work - it can withstand up to 20 folds-folds. With a neat and proper installation   the wire should not experience such loads.

1. Electric brush; 2. Column: 3. Crate: 4. Crate; 5.UZO: 6.Automatic switch VA: 7. Consumers;

It should be noted that all modern electrical appliances have a ground wire, at the same time, an electricity network built in Soviet times is not equipped with a ground loop. Modern houses have their own outline of the earth, and if there is none - very often electricians connect the ground contour to "zero".

  How to calculate wiring

At the beginning of electro installation works   should determine what the total load will be in the house: lighting, iron, TV, computer, microwave, oven, electric stove, kettle, heater, various kinds of tools. For this we use the table:

After calculating the total load, you must select the input cable. The whole electrical load of the house falls on it.

After selecting the input cable, we proceed to calculate the rosette groups and lighting groups.

Important! Remember: lighting and all sockets in the house must have separate circuits and machines.

When calculating each rosette group, the maximum installed power should not exceed 4.5 kW per socket. For electrical wiring with copper conductors - it is 2.5mm2, for aluminum - 4mm2. Protective circuit breaker   should be at 20A.

If you do not plan to include powerful 2-3kW devices into it and want to save on the wire cross-section, you can not, after a few years the interior of the house can change and those sockets where there was no load will become under load.

Recently, few people have used aluminum wires to calculate and install electrical wiring. Specialists are increasingly using copper. Its physico-chemical properties are better than those of aluminum, the lines of service last for 10-15 years. In addition, according to the last seventh edition of the PUE, it is prohibited to use aluminum wires with a cross section of less than 16mm2.

  Installation of electrical wiring by one's own hands

The cable was selected, the total electrical load was calculated. You can begin the installation. Remember that the quality of installation will depend on the operation lines of the entire wiring. For residential buildings, it is not so difficult to conduct the installation of electrical wiring with their own hands, while the projects of power supply and installation work are not cheap.

At work it is necessary to remember:

• the wiring must be safe in service;
• fireproof;
• ensure minimum costs for installation and operation;
• the minimum electrical losses   in the cable;
• lines of operation up to 40 years;
• reliability of cable and work.

At the beginning of the installation work, you should determine which type of wiring you will use:

Open posting   - laid directly on the finish of the walls, or mounted in ducts, electrical trays or corrugations, even under plaster.

Hidden Posting   - The cables are laid directly on the wall in the plaster layer.

Choose a wire:

Wire PNPP, VVGng, VVG, NYM - used for outlets and lighting with concealed wiring.

Wires, PGVP, PUGNP - with external installation.

If you have a mixed type of wiring, use it for hidden wiring   Flexible wires are also available. It should be special attention   quality of wire connections. After all, reliable wiring is a securely connected wiring.

  Power supply of a country house

The first thing you will need to do to organize energy supply a country house, this is getting normative documents   and permission to connect to an overhead line. The main input cable is SIP (self-supporting insulated wire). If an input from the input point to the overhead line is more than 25 meters, additional support is required. The height of the entry should be less than 2.75 m, the wall pass must be made in accordance with the requirements of fire safety.

Maximum consumption per a private house   is 15kW. To protect overhead lines on a branch to the house, energy companies establish individual power limiters,which disconnect the consumer when a certain current is reached.

A simple scheme is proposed for drawing a single-phase input into a house.

1. VA-101-2 / 50; 2. One-phase meter; 3.UZO-01-2-63 / 30; 4. Crucial; 5. The crate; 6.7.8.VA-101-1 / 16; 9. VA-101-1 / 32; PE-protective conductor; L-phase; N-zero;

The number of cores of the input cable depends on whether you have a single-phase (2-core) or three-phase (4-core) network.

The branch is arranged by means of calcining clamps.

Since the power lines do not have a ground loop, it must be manufactured by yourself. To do this, you need 3 reinforcing bars with a diameter of 16mm or more, which drive into the ground to a depth of at least 0.5m. The bars must form an equilateral triangle with a side length of 3 m. Between them, the rods are connected by a 4 * 40mm strip or wire, but not less than the cross-section of the phase wire. The joints are carried out by welding or bolting. The resistance of the ground loop must be less than 30 ohms.

The internal wiring of the country house will not differ from the accepted norms and standards. All calculations remain the same.

Calculation of electrical wiring in the apartment is required in order to avoid unnecessary costs, or vice versa, so that the material does not end in the midst of work. As a result of calculations, it becomes clear how many wires and what section is needed.

Calculation of the length of electrical wiring in the apartment, calculation of the length of the wire

To calculate the number of wires for wiring, you need a calculator. The required length of the wire depends on the number of sockets, lamps, switches and their distance from the junction box. First, on the walls and ceiling, a pencil is marked with future electric points, then with a tape measure the length of the wiring from them to the box is measured. Distances can not be measured diagonally, since wires are only laid vertically and horizontally according to the norms.

To the total length of the wire, it is necessary to add 20-30 cm to each point, which are necessary for twisting in junction boxes and for mounting sockets, switches and lamps. Calculation of the wire to the private house is done in the same way, but meters are added, which are necessary for connecting the home electrical network to the ground loop.

When planning cash outlays, you need to take into account that the wire is sold in bays of 50, 100, 200 meters. A wire sold by an arbitrary footage is rare.

Calculation of the cross section

Correct selection of a section allows to avoid unnecessary material costs and short circuit. Electricians select the wire cross-section according to the load planned for it:

• load up to 3.5 kW (sockets for household appliances) - minimum cross-section 2.5 mm:
• load up to 2.3 kW (lighting, computer outlets) - minimum cross-section 1.5 mm;
• a separate line for the split system - cross section 2.5 mm;
• the line to the electric stove is 4-6 mm.

Selection of automata

Automatic machines are divided by capacity. Usually the apartment has a total of 50 amp machine. The total number of automatic machines depends on the number of junction boxes, in addition, you need to add automatic machines: one (20-25 A) per split, one (20-25 A) per washing machine, one on an electric stove (25-32 A). If the lighting is made on a separate machine, it is sufficient for it to have a power of 10-16 amperes.

Calculations of the number of wires and automatic devices are simple, they can be done independently. Visual calculation of electricity for the apartment can be viewed in our video.