Apartment and villa

Calculation of electrical wiring in the apartment and the house: the criteria and calculation rules

Calculation of electrical wiring in the apartment and the house

From school physics course: "The movement of charged particles causes the heating of the conductor." Most likely, this axiom is known to you, but did you know that the amount released during the movement of heat depends not only on the intensity of the particles themselves (amperage), but also on the section of the conductor. If the wiring in the building in a normal operating mode, the waste heat is simply dissipated to the surrounding space, without affecting the characteristics of any electromechanical cables or the quality of the supply. If payment was made wiring incorrectly, in the first days of its operation, you may find a violation of the integrity of the conductive cores and the insulating layer. This happens because of the overheating of the banal, which was caused by your own improvidence.


  • What should be done?
  • Competent calculation wiring
  • Do I need a power supply
  • A bit on the Protection and "accessories"

What should be done?

Always carried a little - it knows every electrician. That is why in a suitcase with a professional installer can not find one skein of this important material.

For starters, if you are really set about mountingwiring, all you need to fathom and to calculate. To do this, you will need regular Roulette. Consider all the angles, ledges and niches, count the number of appliances that will benefit you and your home and multiply the resulting figure by 15%. This is a standard margin during technical calculations.

Exemplary wiring plan

Exemplary wiring plan

If you desire to run around with a tape measure on a three-storeycottage or apartment of 300 square meters. you do not have meters, but to know at least a ballpark figure you still need, you can use a simple approach: the total area of ​​residential and commercial premises in square meters multiply by 2. For example, your apartment has an area of ​​72 square meters. m, then you will need to buy about 150 meters of electrical cable. A terrible figure? Not at all! Now, if in the case enters the designer, gushing creative ideas, while the total amount of your wiring costs can really scare you. Spot lights, wall sconces, LED Strip, Chandeliers - all this requires an insane amount of wires.

And if you need more than one type of cables? Then take the risk and the rate of 1: 2 - one part will go on lighting apartmentAnd two others - to its power supply. For laying the individual cables "special purpose", for example, to electric cookers, air conditioners, washing machines need to make accurate measurements, and you can buy the usual three-wire cable for small household appliances.

Types of cables and wires

The types of wires and cables - the choice is huge

Competent calculation wiring

Most often, making calculation of the wiring in the houseElectricians offer to buy three-core wireor cables with aluminum or copper conductors enclosed in PVC insulation. These materials are ideal for flush - they do not heat and can last for decades. To open the assembly method wires and cables will also work, however, this method is now practically not used, except in the case where it is impossible prodolbit wall.

Old wiring

Old wiring - source of increased danger

In the table you will find information about the type of wire and limiting current strength for it and use this information in its calculations.


Table for calculating the cable section depending on the load

Now in more detail. As you can see, the electrical wiring bandwidth is not determined in kilowatts, and in amperes. However, when it comes to calculating the wiring for connecting the plot or some device, you will need to start from power, that is, from kilowatts. This relationship can be expressed by the following formula:

P = U ∙ I ∙ cosφ

where P - connectable device power (W), U -voltage (V) and cosφ take the unit, if the calculation of the wiring in the apartment is made for large areas, or even omit it if the apartment or house have a modest size.

Further. We express our current strength as the ratio of capacity to be connected to a voltage by the formula:

I = P / U.

For example, let's calculate the current insingle-phase circuit with connected to it 10 standard incandescent lamps at 100 watts each, a microwave power of 1 kW, and 2-kilowatt electric kettle.

The total capacity of all devices: 10h100 + 1000 + 2000 = 4000 watts. Mains voltage 220 V (to take a reference number). Dividing the power voltage obtain 18.18 A. That is, in the circuit contact portion is calculated amperage equal to 18.18 A. Now look at the table and determine for yourself what type of wire is most suitable.

Thus, the wiring section of calculation is quite simple, if, of course, have any idea of ​​a school course of Physics and know a few useful formulas.

Do I need a power supply

Of course, the power supply of the installation wiringtake into account the need, but it is not necessary to go crazy - everything should be within reasonable limits. Some electricians, in order to cash in on anything ignorant host housing, offer the latest purchase for normal room (nursery or bedroom) with a 6 mm2 cable, while the lead-in cable the entire home or apartment has a cross section of 4 mm2. Hellbent - otherwise you will not name! Explain such as electricians thrifty simple: the more devices in the home, the greater the need kabel.Odnako, this reserve power is not needed - it will only lead to additional costs for the purchase of cables and their installation.

Reasonable thrifty minimize yourfinancial costs, and without compromising safety and reliability. True power wiring made payment will save you money at the same electromechanical characteristics of conductors will not be affected. And this applies not only to cable cross-section, but also the structure of the line. Single-line wiring diagram will reduce the length of the cable, and then decrease, and timing assembly work and material costs.

A bit on the Protection and "accessories"

With the wires a little understood, and how protective devices, switches, sockets? How many are needed?

Protective devices instantlydisable the network in the event of leakage in excess of the nominal value. This miniature device is required to be set for high-power appliances such as water heaters and washing machines. In addition, to protect the entire network need to use circuit breakers that instantly react to short-circuit or overload and shut off from the power network.

As a result. For a typical city apartment, you will need: copper or aluminum cables 1.5 mm2, calculated on the current strength of 16 A (figure may be different, depending on your home), the cable cross-section 2.5 mm2 for sockets designed for amperage 25 A circuit breaker - 10 A and 16 A. power consumption of electrical appliances you can find the data sheet.


Electrical wiring in the final version (before finishing work)

In addition to all that you have just read,there are plenty of other aspects, such as, ambient temperature correction coefficient, the coefficient for jointly laid devices, and so on, which must be considered when calculating the electrical wiring. Therefore, for your own peace of mind, contact the professionals, especially in the case where the energy-intensive devices and powerful power-consuming equipment with reactive load will be used in your home. the full power of your home project they are designed without any problems, you just need to make it a reality.

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