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On how correctly chosen the wire size for wiring depends on the future performance of equipment and the safety of your home. Yes, electricity is not only light, heat and comfort, but also dangerous matter, if the wiring is faulty or does not correspond to the load used. Therefore, when choosing the type of wire, first of all, you need to focus on quality and safety.

Table of Contents

  • 1 Selection of Cable for Wiring
    • 1.1 Driving Cards
      • 1.1.1 Table: Power Cables with PVC and Rubber Insulation
    • 1.2 Selection Criteria for Wire
      • 1.2.1 The
        • 1.2.1
          • 1.2.1
            • 1.2. Power Calculation
              • 2.1.1 Table: Calculation of the copper cable cross-section for power and current with open wiring
            • 2.2 Current load calculation
            • 2.3 Length calculation
            • 2.4 power and current cables and wires for connecting a private house
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Choosing a cable for wiring

Electrical wiring consists of cables, wires and fasteners between them. A wire is a single conductor, covered, depending on the place of use, with an airtight, nonmetallic sheath, winding or braid made of various materials.

The cable consists of several wires combined under a single sheath.

Marking of wires

The wires differ from each other:

  1. The material is copper, aluminum, aluminum copper.
  2. The type of shell.
  3. The cross section of the wires is from 0.35 to 70 mm2 and more.
  4. Insulation.
  5. Rated voltage.
  6. Number of cores.

The name of the wires is an abbreviation in which the initial symbols of the materials from which they are made, the number of wires and the sectional area are encrypted. For example, under the label AVVG 4 * 2.5 hides an aluminum cable with 4 conductors in vinyl insulation, covered with a vinyl sheath and not having armor. Usually such cables are called bare. When the cable is made of copper, the letter "A" no. For ordinary premises, the most commonly used cables are the following brands:

  • VVG - round or flat wire for rooms with normal humidity. Copper conductors, single core. Modification VVGng - non-combustible, does not propagate combustion during installation in bundles. Execution of VVGng-LS is the same, but with low smoke emission. These types of cables are the safest of all. The number of lived in the cable - from 1 to 4;
  • AVVG - a round or flat cable for laying in rooms with normal humidity. Aluminum conductors, single core. It is not subject to burning. The number of lived in the cable - from 1 to 4;
  • NYM is a non-combustible round cable with single core copper conductors. Analogue of domestic cable VVGng;
    The NYM-labeled cable is a high-quality flexible cable with copper conductors sheathed in PVC
  • PVC cable - a round cable with multi-conductor copper conductors;
  • SHVVP - flat cable with copper stranded conductors. The maximum cross-section of cable ShVVP - 0.75 mm2.Used to connect electronics and home appliances.

Table: PVC power cables with rubber insulation

marking designation
AU aluminum conductor and the steel shell
AA aluminum conductor and aluminum sheath
B armor of two steel strips from corrosion-resistant coating
B( first) PVC insulation
The( second) PVC sheath
G without a protective layer over the shell
Shv sheath of extruded PVC hose
Shp sheath of extruded polyethylene hose
K armor round of round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round round coffings of round round round of round couting rings of the round round couting rings of the round round couting rings of the round round couting rings and round rings that are round to 20dies
C lead sheath
O individual shell on top of each phase
P rubber seal
HP sheath of rubber that does not support combustion
Ps insulation or sheath of self-extinguishing polyethylene
Ilb insulation vulcanized polyethylene
ng not supportburning
LS reduced smoke emission
CG cable flexible

Selection criteria for wire

An insulated electric wire is suitable for a flat,designed for domestic use and designed for a voltage of 220–380 volts, and it happens:

  1. Copper. Currently, copper cable is most often used, since the resistance of copper is less, respectively, such a wire can pass more current and provide more power. Also, the copper wire is durable and strong, easily amenable to tinning, soldering and welding using the most affordable tools. The minus of copper is that it is rapidly oxidized, as well as high cost. In addition, if the connection is not obscure, then it will eventually conduct the current worse and begin to warm up.
  2. Aluminum. It is a chemically more active material and is lighter than copper. But his conductivity is two times lower. Aluminum is welded only in inert gas and soldered using solder and flux. And it only connects with aluminum - through bolts and nuts. In the process of assembling joints( except welding), stripping and lubrication is required. Aluminum and copper cannot be directly connected, since the point of contact will quickly collapse. Therefore, these two wires are connected only through the terminal block or the third metal. The cost of aluminum wire is several times lower than that of copper.

Wires and cables are single-core and stranded. For hidden wiring, single-core wire is more often used, since it is rigid, therefore it cannot be bent multiple times. Stranded wire is soft and well withstands numerous bends, so it is suitable for open wiring and use as a cord to connect electrical engineering. The main rule is to stay on one material and make all the wiring out of it.

Multicore cable withstands bends and takes the form of complex surfaces well.

Video: Which cable to choose for wiring

Calculation of cable section

Proper choice of wire size for home wiring is extremely important, because the consequences of incorrect calculation can have such consequences, which should be 100.a, 17cost unnecessarily expensive;

  • if the core diameter is smaller than needed, the wires will heat up and melt the insulation material, which can cause spontaneous combustion of the wiring and short circuit.
  • To avoid such problems, before installing the wiring, you need to correctly calculate the cable section, taking into account the indicators of current strength, power consumption of electrical devices and the length of electrical lines.

    Power Calculation

    Any cable has a rated power for which it is designed, provided that 80% of electrical devices are connected. Why exactly 80%?Yes, because all 100% of consumers are rarely included at the same time. To determine the load, the power of all electrical appliances to be used is calculated first. The sum of these values ​​plus 20% of the stock will determine the parameters of the input cable entering the house. However, it is not at all necessary that the rest of the wiring be just as powerful. Simply put the cable on the terminal block, and from it through the machines put the wires of the required value into the room. For example, high-power appliances such as a washing machine is best connected to a separate line. The formula for calculating the wire for an apartment is as follows: Ptotal =( P1 + P2 + P3 +. .. + Pn) * 0.8, where P1, P2. .. Pn is the unit power in kW, the coefficient 0.8 is just those 80%.

    Typically, the cable is put on the input of the machine, and then diverges on consumers

    Consider an example.

    1. Suppose when calculating it turned out that the total power consumption is 14 kW.According to the formula, multiply this figure by a factor of 0.8 and get a figure of 11.2 kW - this will be the actual load.
    2. We look at the special table and select the appropriate value in the corresponding column. For a voltage of 220 V, the number 11 for a single-phase network will suit us. Conclusion - the cross section of the wire should be 6 mm2.

    Table: calculation of the cross-section of a copper cable for power and current with open wiring

    Open wiring Section, mm2
    Current, А Power, kW
    220 V 380 V
    11 2.4 -strn - 0.75
    17 3.7 6.4 1
    23 5.0 ​​ 8.7 1.5
    26 5.7 9.8 2
    30 6.6 11 2.5
    41 9 OSDusually use a cable with a section of 1.5 mm2, and for sockets - 2.5 mm2 and more.

    Calculation of the current load

    To calculate the current load, sum up the current consumed by each of the used devices( information can be found on the back side), multiply the figure by one and a half, and then find the value in the corresponding table. It shows that for 14 amps( or 4.3 kW of power at a voltage of 220 V), a copper cable of 2.5 mm2 is recommended. There are special calculation programs on the Internet that can be used for free.

    Calculation along the length of

    With an increase in the length of the electric line, the current losses increase due to the resistance of the conductor, so for a long route you need a conductor with thicker conductors. To get the result you need:

    1. Calculate the resistance of the core by multiplying the specific resistance by the length of the line in meters. The length must be multiplied by two, because the current flows in one line and returns in another. The formula is as follows: R =( p * L) / S, where p is the resistivity of copper, equal to 0.018 Ohm · mm² / m.
    2. Calculate voltage loss. To do this, sum the current through all connected devices and multiply by the resistance found in the previous step.
    3. Determine the percentage of losses. The resulting loss value is divided by the existing voltage in the network and multiplied by 100%.If the resulting figure is less than 5%, then the vein will withstand, if more, then a more powerful conductor is needed.

    Selection is usually made on the basis of personal preferences and financial ability. There are electricians who put all the wiring in the house with a single-core wire, and there are those who prefer a stranded cable. It does not matter, the main thing is that its cross-section corresponds to the power consumption.

    It is not recommended to use PUNP wire for home wiring due to poor-quality insulation that loses its operational properties. Also not recommended wire with rubber insulation labeled PRTO, PRN, PRI.Also currently not used cable with aluminum conductors APRTO, APR, APV, APPV.

    Video: Calculation of cable and wire cross-sections for power and current for connecting a private houseIf there are no tags on the bay, then buying such a cable is dangerous.
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