Which wire is used for wiring. What is the best wire to use for wiring in the house. What to look for when buying a cable

It would seem, take any wire and conduct electricity to the house. But no. The choice of cable depends on the operating conditions, the method of its installation and the material of the walls and ceiling. Therefore, the wire for the apartment and the cottage is purchased differently.

Let's figure out which wiring is best for the house, what parameters it should have.

For an ordinary person, the words wire and cable have the same meaning. But for an electrician, these are two different concepts:

Today's safety rules allow the laying of insulated wire only for hidden wiring. To do this, insulated cores must be placed in the corrugation. But the cost of three separate wires and a corrugated tube will be higher than the cost of a three-core cable. And pulling the wire through the corrugation is a laborious job. The cable also has good external protection, so the tube is not needed for it.

Conclusion : for the home, cable is preferable to wire. This is saving, reducing the labor intensity of electrical work and ensuring safety.

And what kind of cable is needed for wiring in the house: two-, three- or four-wire? To replace the old type of two-wire wiring, the cable conductor must contain two cores, and to replace the new type of three-wire wiring, three. If you plan to install two-gang switches, then take a four-wire conductor.

Advantages of stranded wire

If the current-carrying core of the occasion is a monolithic wire, then this is a single-strand conductor. If it consists of many thin wires (hairs) woven together, it is a multi-filament conductor that has the following advantages:

• Does not break when twisting and bending;
• Suitable for permanent mechanical loads;
• Resistant to vibration load;
• With the same cross section as a single-strand wire, it reduces current losses on the resistance.

Multi-strand wire is more expensive. And because of its softness, it is harder to stretch it when installing hidden wiring. So what kind of wire to use for house wiring? Single-strand wire is easier to run, but it can break when pulled through a wall or at folds. With multi-hair, the opposite is true, but in addition it saves electricity. Make your choice based on your personal preferences.

Aluminum or copper wiring?

What wires are needed for wiring in the house: aluminum or copper? Today, aluminum is used only to replace a section of old aluminum wiring. And copper - in all other cases. Advantages of copper wires:

• Copper is more ductile, so when twisting and bending, the risk of breaking the wire is lower;
• Copper has less resistance, which is why current losses are reduced by 1.3 times;
• Copper wires are less susceptible to oxidation, which leads to overheating and a fire hazard.

Attention! When replacing a section of aluminum wiring, you can not buy copper wire. When copper is combined with aluminum, an oxidative process occurs. The risk of fire increases dramatically.

Section calculation

The cross section of the wire depends on the load in the circuit. Calculate the power of all electricity consumers that can be connected at the same time. This is a chandelier, a computer, a TV for a bedroom or a hall, and for the kitchen - a stove, a washing machine, a dishwasher, a microwave, a boiler and a lighting system. Round up the resulting value, and then add 20% of the result.

Example. The sum of the capacities of consumers in the circuit is 4.5 kW. We round up to 5 kW, and then add 20% - 1 kW. We get 6 kW. Now we look at the table and look for a line for a copper or aluminum cable with the required power. It can be seen that an aluminum cable with a cross section of 6 square meters is quite suitable. mm, or copper with a cross section of 4 sq. mm.

Cable brand

To know which cable to choose for wiring in the house, you need to determine the conditions for its operation. The brand of wire will depend on this. For a private house, three main zones can be distinguished: interior, street, bath. In this case, it is necessary to take into account whether the wiring is hidden or openly mounted.

For concealed wiring

Cables of brands are suitable for kitchen, bedroom and other premises:

There are no specific selection rules. Take what you feel is best. But electricians prefer the German NYM cable. It costs more, but the quality of the wiring will be higher.

For open wiring

In wooden houses, open-type wiring is desired, although no one forbids using it for stone buildings. In this case, the choice of cable determines only its color:

• VVG is painted black;
• NYM grey;
• PVS is performed in white or orange;
• SHVVP is standard white, although other colors are rare. Ask the seller about them.

And what kind of wiring is better to do in a wooden house? It is not the color that is important here, but the fire protection. Only three options are possible here: Russian VVGng-LS or VVGng, as well as German conductors NYM.

Advice! If the color of the wire does not suit you, purchase a cable duct and lay the conductors in it. The channel can be colored as you wish.

For wiring outside the home

If electricity is supplied to the house not by air, but by land, then you need to take AVBBSHV cables if you have aluminum wiring, and VBBSHV if you have copper wiring. This grade is armored with steel tape, which is applied after the insulating layer. Steel is protected by rubber from groundwater. This design resists mechanical damage, which is possible with inaccurate trench digging and soil movements.

And what cable to use for wiring outdoors, where precipitation, large temperature changes, sun and wind are possible? VVG and AVVG cables are not afraid of this. They can be laid on the roof and wall.

For a bath

It is impossible to conduct sockets and switches in the steam room. The wire in the bath is needed only to provide light. But it has high requirements:

• Moisture resistant;
• Ability to withstand temperatures up to 180 degrees.

These requirements are met by Russian brands RKGM and PVKV, which are protected by a silicon-containing organic shell.

How to read cable brand?

Using the example of the VVGng-LS 3x1.5 cable, let's analyze how to read the marking correctly:

• If the letter “A” is in the first place, then this is an aluminum conductor. There is no this letter in the wire marking from the example - it means that this is a copper conductor;
• The first "B" says that the insulating sheath of each cable core is made of polyvinyl chloride (PVC);
• The second "B" - that the overall sheath of the cable is made of PVC;
• "G" - the first letter of the word "naked", which means the absence of additional protection;
• "ng" - from the words "does not burn", does not support combustion;
• "LS" - added if the wire does not emit smoke;
• The first number is the number of cores in the cable. There are three in the example;
• The second number is the cross section of one core.

What should you be aware of when buying?

Two pitfalls can be distinguished, they are easy to stumble upon due to inexperience:

• Purchase of cable without marking on the protective sheath. Under this guise, you can sell any wire, even prohibited for installation in residential premises. If you buy wire without marking, and subsequently you have a fire, the insurance company will not pay compensation, because cables prohibited for use in wiring will be found on the spot;
• Purchase of a cable from unscrupulous manufacturers who save money by reducing the cross section and thickness of the protective sheath. It looks hard to spot the trick. But imagine what will happen if you calculated the power in the electrical network, calculated the required conductor cross section, and installed a wire of a smaller cross section? The wiring will get hot, a fire may occur. And the insulating sheath is so thin that it will easily burn through or simply deteriorate, exposing the wires.

15% of fires are caused by laying wire that does not meet safety standards. Poor quality wiring is installed out of ignorance or, if desired, to reduce the cost of electrical work. But at the same time they forget that human life is more valuable. Do not save on the purchase of a cable in order to protect your family and get high-quality wiring that does not require repairs for decades.

In houses of old construction, in most cases, it has already exhausted its resource and must be replaced. In addition, old household networks are absolutely not designed for the power of modern household appliances. Of course, there are some important factors to consider when purchasing new cables. About which wire to use for wiring in an apartment is best, and we'll talk in this article.

What to consider when choosing

The first thing to decide is the cross section of the future cable. This setting depends on the following factors:

• the length of the network, and hence the resistance;
• the expected load on it;
• manufacturing material.

When deciding which wire to use for wiring a short network with a large load in an apartment, one should be guided by the heating conditions. for long lines it depends to a large extent on the magnitude of the resistance. Also in this case, mechanical strength is important.

As for the material of manufacture, two types of cables are currently used: copper and aluminum. In the first case, the cross section will be smaller, in the second - larger. For this reason, the vast majority of apartment owners currently prefer to run copper cables in their apartments, which are distinguished by better conductivity.

Consumed load

The cross section of the electrical wiring in the apartment should be such that the owners subsequently have the opportunity to connect devices of the required power. The current value for this particular household appliance is determined by the formula I \u003d P / V, where P is its power (you can see it in the data sheet), V is the mains voltage. In a household, it is usually 220 V. Thus, for example, for a heater with a power of 2000 W, the current value will be 9 A.

Next, the total current of all prospective consumers is calculated. The cross section of the copper wire is selected taking into account the allowable 10 A per square millimeter. Aluminum - 8 A. In the event that the wiring is hidden, these values ​​\u200b\u200bshould be multiplied by a correction factor - 0.8. almost never used in the apartment. However, if for some reason you have to choose this option, you should use a wire with a cross section of at least 4 mm 2, which has sufficient mechanical strength. With greater accuracy, the permissible current load on copper and can be found in special tables.

It is better to choose wires for wiring in an apartment with a certain margin of power. This will make it possible in the future to connect new electrical appliances to the network, the purchase of which is currently not planned.

In ordinary city apartments, copper wire with a cross section of 1.5 mm 2 is most often chosen for lighting, and 2.5 mm 2 for sockets. It is better to stretch a 4 mm 2 cable into the kitchen, since there are usually a lot of powerful household appliances - a stove, a refrigerator, a dishwasher, etc. device to be used.

Resistance

The question of which wire to use for wiring in an apartment also comes down to the correct selection of the cross section in terms of possible voltage losses. Lines even in city apartments are quite long. In this case, the voltage losses in the cables can reach an unacceptable value. The choice must be made in such a way that this value does not exceed 5%. To calculate voltage losses, the load moment must first be calculated. To do this, the power in kilowatts is multiplied by the length of the cable in meters. Further, according to special tables, the actual percentage of loss is determined. It will depend on the load moment, the cable section and its length. There are separate tables for three-phase and single-phase networks. However, you should be aware that they indicate the percentage of losses without taking into account the heating of the cable during the passage of current through it. Therefore, in this case, the wire cross-section should also be chosen with a margin. That is, look at the table for the value corresponding not to 5, but to 4%.

soft wires

For residential areas, soft flexible cables are usually chosen. Each core in this case consists of a large number of thin conductors. Such cables are easy to pull through apartments of complex layout with a large number of bends. The only drawback of soft wires is that when connecting the wires, you have to crimp them and press a special tip onto them.

Rigid

There is another type of cable - rigid. In this case, each core consists of one conductor. In principle, it does not matter which wires for wiring in the apartment will be chosen - flexible or rigid. The main thing is that the cable matches the loads on it from consumers. For a city apartment, three-core options with a ground wire are usually chosen. The core insulation in this case will have different colors. Brown or red correspond to the phase wire, blue to zero, yellow to ground.

Most commonly used wire brands

One of the most popular options is the NYM cable, which is very good for wiring in an apartment. It is a flexible version of single-wire cores and has a round shape. Another advantage is the presence of two insulations. The latter circumstance makes it more fireproof.

Another variety often used in city apartments is single-wire, which can be round or flat. This option is more compact than NYM, and therefore more convenient to install. Among its advantages, among other things, can be attributed not too high cost.

The third common option is multi-wire PVA. This round cable has very good flexibility. Most often it is used for household appliances as a network wire. However, for the installation of lines, it is suitable very well.

What else you need to know

In the event that the wiring is to be pulled behind a plasterboard finish or a false ceiling, a flame retardant cable should be used. Such options are marked with the letters "NG". It's even better to use with an "ls" index. The insulation of such wires in the event of a fire will not emit a lot of harmful smoke and gases.

It is best if the cable for wiring in the apartment is double insulated. In any case, saving on this is not worth it. Otherwise, for example, when flooding in an apartment, a fire may also occur, since single insulation is quite often simply damaged during installation or during operation.

How to choose switches

So, you have decided which wire to use for wiring in the apartment. However, cables are, of course, far from the only element of the network. In addition to them, you will need to buy more and other components. Switches are chosen, first of all, based on what kind of wiring is used in the apartment - open or closed. Of course, the first option in this case is used extremely rarely. Therefore, for a city apartment, most likely, you will need to purchase switches for hidden wiring.

In addition, these network elements are available with screw and screwless clamps. The first option can be a good choice if the electrical wiring in the apartment is stretched using aluminum cables. The latter can melt slightly over time and begin to spark. In this case, it will be enough just to tighten the screws. For copper wiring, switches with clip-on terminals are usually chosen. They are more convenient to connect.

Choice of sockets

This element is best chosen, focusing on the manufacturer. However, you should beware of fakes. In the latter case, for example, an unpleasant odor can come from the sockets. In addition, low-quality goods are often made of too thin or soft plastic. The socket must be heavy enough. It is also worth paying attention to the condition of the grounding contact. He shouldn't bend.

It is worth taking a plug with you to the store and try to plug it into the outlet. Of course, it should not hang out and fall out. For such an option as external wiring in the apartment, as in the case of switches, sockets of a special design are used.

Today on sale you can also find special ones equipped, for example, with USB connectors or LED-backlight. You can also choose this option if you wish.

Well, we hope our article will help you decide which wire to use for wiring in a city apartment. There are many options at the moment. The most important thing is to use cables that are suitable for the power of the devices and are as safe as possible.

Currently, for the installation of home electrical wiring, wires and cables are used exclusively with copper conductors. Wires and cables with aluminum conductors must not be used for internal wiring.

Wires and cables are single-core and multi-core. Stranded wires and cables have two or more cores reliably insulated from each other in a common sheath.

Example - PRTO brand wire(wire with a copper core with rubber insulation in a braid of cotton yarn impregnated with an anti-rotten compound).

The cores of single-core and multi-core wires and cables can be made single-wire and multi-wire.

Cables and wires differ from each other in the type of sheath and names. The sheath of wires and cables serves to protect the core insulation from exposure to light, moisture, various chemicals and prevent them from mechanical damage. The structure of the cable may include armor, and the sheath allows them to be laid in more adverse environmental conditions.

Wires can only be laid in a hidden way, with - only boxes. Cables can be laid open.

The most popular cable for use in home wiring is VVGng, the NYM cable and PUNP wire are less commonly used.

It is best to use a NYM cable to connect to the floor panel. The same cable is used to connect the floor shield to the apartment or room shields (provided that there are such). Usually such shields are organized in private cottages. It can also be used for individual connection of powerful consumers. This cable can be used for everything in an apartment or house, but since it costs more than the VVGng cable and PUNP wire, it is used less frequently for these purposes.

VVG - unarmored protected cablewith copper conductors, PVC insulation, PVC sheath. The cable can be applied in dry and damp rooms.

The VVG cable is not designed for stretching. The insulated conductors of the VVG cable are twisted and have a distinctive color. The inner sheath does not contain filling in the space between the cores.

Rice. 1. VVGng cable

ABOUT the designation "ng" in the name of the cable (VVGng) means that it does not spread combustion when laid in bundles (a composition based on refractory plastic compound is used). If the VVG cable is used instead of the VVGng cable, then in the event of a fire in one of the cables, the flame will spread to other cables, instead of localizing the fire.

The VVGng cable has a wide variety of shapes. It is most convenient to use a VVGng flat cable. In addition, it can also be round, square, sector, and even triangular.

Cable NUM (NYM) - produced according to German standard DIN 57250. The cable can be used indoors with hidden and open laying. Cable NYM can be used outdoors, only out of direct sunlight. Cable NYM It has low flammability and gas and smoke emission, which is especially important for residential premises.

Fig 2. NYM cable

NYM cable consists of copper conductors, an intermediate sheath made of chalk-filled rubber and a sheath made of flame retardant polyvinyl chloride insulation. The use of an intermediate sheath in the design of the cable makes it easy and convenient to cut the cable during installation, increases its fire hazard and increases flexibility.

PUNP - installation flat wire. This is the cheapest wire of all cable and wire products used for electrical wiring in everyday life. PUNP wire is produced with two or three single-wire copper conductors and polyvinyl chloride insulation in a sheath made of PVC-compound. The cores can be painted in different colors.

Rice. 3

PUNP wire is produced only flat. These cable and wire products are used for both power and lighting networks. In the second case, take wires of smaller sections.

I do not recommend using PUNP wire when laying home electrical wiring, since the insulation of this wire is made of cheap materials and loses its properties very quickly when heated. When choosing a cable for wiring, give preference to cables of the VVGng or NYM brands.

Much less often in home electrical wiring, rubber-insulated wires of the PRN, PRI, PRTO brands are used. Wire PRTO is designed for laying in fireproof pipes, PRI - can be used for laying in dry and damp rooms, PRN (protected wire) - in the open air, PRD, PRHD (two-core twisted wire) - only in lighting networks of dry rooms.

For open wiring, it is convenient to use a flat wire with copper conductors and PVC insulation with a dividing base of the PPV brand, as well as a wire with PPP polyethylene insulation. There is a flat wire without a dividing base - PPVS, but it is not very convenient to use it.

The previously used wires with aluminum conductors (APR, APV, APRTO, APPV) are now not used in the construction and modernization of home electrical wiring.

Wire with copper core and PVC insulation PV. PV wires can be single-wire and multi-wire. Wires are available with different colors of insulation. In household electrical wiring the stranded wire PV1 in yellow-green coloring is used for the potential equalization system (DSUP).

Rice. 4.

Wires PV2, PV3 and PV4 are used for internal installation in electrical panels. Wires PV3 and PV4 are usually more expensive , because have a more flexible shell. They are used where wire bends are required.

To power street lamps, underground apply armored cable VBbShv, or a cable with aluminum conductors AVBbShv. This cable is protected by steel tape under a layer of PVC insulation.

Rice. 5. VBbShv cable

VBbShv cable is available with three, four and five conductors. Previously, for these purposes, a cable with copper conductors in a VRG PVC sheath and armored cables with aluminum conductors of the AASHv, AAB, AVVB and AVRB brands were used.

For air branches in our time, the most popular. There are a large number of varieties of such a cable: SIP-2A, SIP-3, SIP-4. The cable has steel-aluminum conductors of high strength. The cores are insulated with special light-stabilized weather-resistant polyethylene, which does not collapse in the open air.

Earlier for making air branches AVVG cables with ordinary PVC insulation were widely used, which quickly became brittle and destroyed under the influence of adverse environmental factors. The use of self-supporting insulated SIP cable solves this problem.

When choosing wires and cables, it is necessary to observe PUE requirements for insulation coloring.

The insulation of the zero working conductor should be blue, the zero protective conductor should be yellow-green. The color of the insulation of the phase conductors must differ from the color of the zero ones. There are many options - brown, red, gray, white, black, etc.

Rice. 6. Color options for wires and cables

It is also very convenient to use a different color of phase conductors for each section of the wiring, as well as different colors of core insulation for power and lighting wiring.

If you choose and then install the wiring with a wire or cable without observing the requirements for the color of the cores, then in the future this will lead to significant difficulties in maintaining and repairing such wiring, and the installation process itself can be very complicated, especially when using a large number of switches and sockets. In addition, the use of wires and cables with insulation of the same color is a violation of the PUE.

You can’t argue with the fact that over the years there are more and more electrical appliances in our house! And even despite the fact that modern products are mostly energy efficient, wiring sometimes cannot withstand loads. Therefore, a cable for wiring in an apartment is a choice that cannot be saved in any way.

Types of electrical wiring cables - understand the designations

Even with minor repairs, for example, wallpapering, be sure to carry out a light one - check the quality of the connections, tighten loose sockets. The amount of energy that we consume has increased by 2-3 times over several decades, and in winter, when various types of heaters are also connected, it completely exceeds the permitted norms.

The wire for electrical wiring in the apartment, used in the past repair, may simply not survive for the next one. So if today you choose which wire to use for wiring, then this choice should be with a serious margin! The safety of your family directly depends on this - More than half of fires are due to wiring problems.

Of course, it is better not to lay the wire without special skills, but to entrust the work to an electrician. However, in choosing blindly rely on someone else's opinion is not worth it. Let's first understand the notation that you will meet on the wire.

It makes no sense to memorize all these designations - make yourself a cheat sheet and feel free to go to the store. For example, the wire is marked as "ShVVP-3". With the help of a cheat sheet, we can find out that we have a vinyl-insulated cord, in a vinyl sheath, and, moreover, it is flat. The three at the end indicates that the wire has a third class of flexibility.

Cable, wire, cord are all different things. A cable consists of several insulated wires (cores) that are twisted together and enclosed in a common insulation. The cord inside has several stranded cores, insulated and covered with a protective sheath.

You should choose based on the material from which the wires are made. If it is aluminum, then keep in mind that it has a lower electrical conductivity, oxidizes quickly and crumbles at the kinks. Besides, the oxide formed has a high resistance, so that over time the quality of the electric current will only deteriorate. The undeniable advantage of aluminum wires is their relatively low cost.

Copper wires oxidize much less, are resistant to environmental influences and are more durable in bends. However, the price of copper wires is significantly higher. And yet, in the calculation of costs, factors such as the frequency of wiring replacement should be taken into account - in the case of copper wires, you will forget about it for many decades, while aluminum can remind you of yourself very quickly.

The cable for electrical wiring in the apartment should be characterized by increased flexibility, since when wiring in the apartment there will be many bends and connections. This condition is not so important for cables that are used outside the apartment. For standard apartments and standard purposes (lighting, connecting household appliances), the following brands are best suited:

1. VVG - as we already know, this is a cable with vinyl insulation and vinyl coating, flexible. By default, there are copper wires inside, but if the letter “A” is still in front of this marking, then aluminum wires are inside. A good wire for hidden wiring (under a layer of plaster, putty);
2. NUM (NYM) is an analogue of VVG, which is produced in Germany. This wire is suitable for both external and internal wiring. Has a round section. Inside - single-wire conductors. The difference from the previous version is less compact, but more flexible.
3. PVA - connecting wire in a vinyl sheath, round section. Inside there are several stranded cores, that is, each core consists of many small copper wires. Mainly used to connect household appliances.
4. ShVVP - flat cord with vinyl insulation. Most often used on household appliances.

Cable for wiring in the apartment - section

The choice of section does not depend on the brand of cable - no matter what wire you choose, special attention should be paid to the section. The cross section is actually responsible for the load that the cable can withstand. To date, the market presents wires with a core cross section from 0.35 mm.kv to 25 mm.kv. For lighting, the optimal wiring is 3 * 1.5 mm2, while 3 * 2.5 should be chosen for sockets.

By the way, both large enterprises and small entrepreneurs can be engaged in the production of cables. It is better not to take into account the products of the latter - it is not known what materials they used and what they saved on. Choose trusted manufacturers and only certified products manufactured in accordance with GOSTs. You are unlikely to find the latter in small markets, so the best option is to shop in large stores, where there is a wide selection of cables for electrical wiring. Remember, saving in this matter is unnecessary - safety is above all!

It is impossible to determine the cross section of the input cable according to the power of electrical appliances available in the apartment. Tomorrow you will buy, for example, an oil heater with a power of 2.2 kilowatts, or a washing machine, also with a power of 2 kilowatts, or an air conditioner with a power of 1 kilowatt. And what? Change the wiring in the apartment? (may even have an extra outlet). Well, the apartment wiring itself is simple. According to SNiP, there must be one outlet for every two square meters of living space, and a double or triple outlet is also considered one outlet. So you must first select the number of outlets and their location, and if there are powerful electrical receivers in the room, then you need at least two groups of lines for outlets, for general use and for a powerful consumer. There may also be an electric stove in the kitchen, it needs a wire of at least 6 millimeters square for copper and an automatic machine for a rated current of 25 amperes, 32 amperes is already a lot. And for other sockets - a wire of 2.5 mm square for copper and an automatic machine for each line for a rated current of 16 amperes. For lighting, according to the nature of work in the apartment panel, we select an automatic machine for a rated current of 10 amperes and a wire with a cross section of 1.5 millimeters square for copper. At the same time, you need to think about the fact that if too much load is plugged into any outlet, then, according to the current characteristics of the machine, a 16 ampere machine can "hold" a current of 24-25 amperes for 40-50 minutes, although the simultaneous overload of several lines to sockets is unlikely. Well, we have decided on the number of lines and machines, their denominations. Now we determine the maximum possible current load on the apartment, given that any machine can be loaded with 100% current and it will not turn off. We summarize the rated currents of all machines and multiply by a utilization factor of 0.7. For example, we got 120 amperes. 120 *0.7=84 amps. Yes, of course, such a load is possible in rare cases, for a short time, and if we used LED lamps for lighting, then a machine with a rated current of 10 amperes will never be loaded with a current of 10 amperes, but the input cable should work reliably in any case. For such a load, only a 60-ampere meter is suitable; for a higher rated current, regional energy meters are allowed to be installed only in exceptional cases. Well, since we use LED lamps for lighting, then such a counter will do. It will withstand a very short overload. Now the introductory machine must be at such a rated current that would allow a short-term overload without shutting down. Considering that a maximum cable or wire with a cross section of 10 square millimeters of copper can be connected to a meter for a rated current of 60 amperes, we select an introductory machine for 40 amperes. It will reliably protect the meter. According to the time-current characteristics of the automaton of group C, it can be seen that it can withstand a current of 60 amperes for 40-50 minutes. Now you need to measure the resistance of the phase-zero loop at the installation site of the apartment shield in order to make sure that the current cutoff of the machine is working. It should be no more than 0.5 Ohm, otherwise you will have to reduce the rated current of the machine and redo the entire apartment shield. We made sure everything is in order. Now we check the cross section of the input cable or wire. The rated current of a two-core copper cable or wire is -55 amperes according to the PUE. It goes through load and overload. We check it by the heating temperature at an ambient temperature of 40 degrees Celsius. In summer, the input line, even without current, can heat up to such a temperature, especially in a closed apartment panel, where both machines and relays emit heat, and the nominal ambient temperature according to the PUE is -25 degrees Celsius. Therefore, we apply a reduction factor for the current load of 0.81. This means that in the summer, in the heat, the input cable will withstand no more than 40 * 0.81 = 44.55 amperes, approximately 45 amperes. This is not enough in terms of current reserve in the event of an overload of 60-70 amperes. The cable can go out of order. In addition, one input cable to the apartment does not meet the SNiP on the reliability of power supply. Therefore, we finally accept - lay the input with two independent lines according to the "two for one "cable or wire with a cross section of 10 millimeters square over copper. We check. In the worst case, each cable or wire can withstand up to 45 amperes of current, two -85-90 amperes. Even with an overload of 50%, the cables will withstand the load in any heat. We put a terminal block in the floor shield, we lay the section from the meter with a single-core copper wire with a cross section of 10 millimeters square for copper, which can withstand a rated current of 80 amperes according to the PUE, from the terminal block we lay two cables or wires in parallel along the route to the apartment shield, connecting them in parallel on the terminal block and in on the input machine. In case of failure of one cable, we simply bite it out and change it, and the apartment receives power through the remaining cable, which meets the requirements of SNiP for the reliability of power supply. Well, there was a riser in the entrance. If it is made with an aluminum wire of 6 square millimeters, you can temporarily reduce the rating of the introductory machine in the apartment panel to 25 amperes or 32 amperes, or use apartment wiring, taking this into account, otherwise the overload protection in the switchboard house will work. But the bottom line is that your area of ​​responsibility and delineation of authority begins at the ends of the wire or cable connected to the meter. And everything else is not your competence. So let them change the wiring in their areas in accordance with modern loads and requirements for it.