NYM cable - detailed explanation of the abbreviation, design features and technical and operational characteristics

This is how the modern civilized world works - there is hardly a single room in a residential building or industrial facility that is not supplied with cables that transport electric current for lighting networks or power a variety of power devices, instruments and mechanisms.

online store, it is very easy to get confused, because the price and technical characteristics of conductors vary significantly. In this case, it makes sense to seek advice from specialists or “Google” yourself.

Sometimes the problem of choosing a cable, if a specific brand is not specified in the energy project or the requirements of regulatory documents, is solved very quickly by purchasing a universal wire NYM , the use of which is justified in many areas of application, especially for solving household electrical problems. In this material we will look at what a NYM cable is , its main technical characteristics , give a breakdown of the markings and compare it with its “competitors” analogues.

Technical characteristics of the NUM cable

Let's start with the fact that various modifications of this cable are produced in Russia.
There are those that comply with German standards (VDE), there are those manufactured according to technical specifications, and as practice shows, each plant has its own specifications. In the second case, the name can be different, here it is NUM, NUM, and NUM. In general, there is no standard. Therefore, often in the market, when buying as if NYM, in fact, a completely different wire is being purchased. In any case, its characteristics may differ from German quality. For example, these are smudges of the compound that fills the interstitial space. The Germans require that this compound be made of chalk-filled rubber. Specifications may contain another material that is less durable and has a low thermal coefficient. Hence the leaks.

Since we started talking about the design, we will continue. So, NUM cable is a power copper conductor. Its conductors can be monolithic if their cross-section is from 1.5 to 10 mm², and consisting of a large number of copper wires, so to speak multi-core, if the cable cross-section is in the range from 16 to 35 mm². At the same time, there are varieties of cable products with different markings:

• NUM-J is a wire with at least three conductors, where one of them must be a grounding conductor, painted yellow-green.
• NUM-O is a cable with at least two cores without a ground wire.

So, the NUM cable consists of copper cores that are insulated with PVC plastic. Next comes a non-flammable layer, it envelops all the veins. And the last layer is general insulation made of the same polyvinyl chloride. Let us add that all the cores inside the cable have different colors, which corresponds to state standards and rules for convenient installation and maintenance.

Other main technical characteristics:

• number of cores: from 2 to 5;
• withstands voltage up to 0.66 kW with a current frequency of 50 Hz;
• This is a flexible cable;
• there is no need to heat during installation;
• installation can be carried out at a temperature not lower than -5C;
• operating temperature: -50С +50С;
• maximum long-term temperature – +70C;
• service life 40 years;
• bend – four wire diameters;
• high resistance to open fire, and NUM wire does not spread flames.

Attention! It is prohibited to use a cable of this brand for laying underground (meaning in trenches).

But laying by air is possible, you just have to take into account the fact that the air is exposed to the negative effects of precipitation, sun and wind. Therefore, in this case, you will have to select the cable according to the current strength with a slight increase in this indicator. For example, if a NUM cable with a cross-section of 1.5 mm² can withstand a current of 30 amperes when laid indoors, then in the air only 24 amperes.

Let us remind you once again that the German VDE standard is very different from the factory specifications, therefore the technical characteristics of cables manufactured according to the specifications will be very different from those manufactured according to the standard. This is especially true for operational safety. For example, if the NUM cable, manufactured according to German requirements, has minor damage, then it can be used. But it is better not to use those manufactured according to specifications, even with minor defects. By the way, German wires must be marked with “VDE” and “NUM”. If this is not found on the cable, then it is a product of Russian manufacturers.

Scope of application and main advantages

The main advantages of using NYM cable:

• Fire safety. The product is manufactured in a protective shell made of a special material that is not subject to combustion. However, there is a risk of fire when laying wires in a bundle.
• Increased elasticity. The cables have a rubber seal.
• Various areas of application. Suitable for underground and overhead installations. With its help, you can make electrical wiring in wooden houses, over long distances and in hard-to-reach areas.
• Availability of color marking. Electrical installation work is carried out quickly and easily, due to the color indication of copper conductors.

A wire with a conductor cross-section of classes 1 and 2 according to GOST 22483 is recommended for use in office and residential facilities. It is resistant to environmental influences and is suitable for installation not only in dry rooms, but also in facilities with high humidity, including industrial buildings and cable racks.

Cores with a cross section of 1.5-10 mm2 are single-wire, 16-35 mm2 are multi-wire. PVC plastic was used as a structural coating. In accordance with the standard, material of different colors is used, which greatly simplifies the installation process.

Experts recommend NYM cable to those who do not know what to choose to improve the fire safety of wiring. The effect of the non-flammable outer shell is complemented by internal filling of the distance between the cores with a non-vulcanized rubber mixture. Due to self-extinguishing, the product does not ignite even under direct exposure to fire.

Design features

VVGng is a power cable with copper conductors. The core insulation is made of polyvinyl chloride plastic. The insulation material contains additives that make it flame retardant. This conductor is available with a number of cores from 2 to 5. For ease of installation, the core insulation is color-coded, which can be done by completely painting the core insulation, or with a colored stripe. The outside of the cable is covered with a sheath made of the same PVC plastic as the core insulation. The core can have a single-wire or multi-wire design. The cross-sectional shape of the core can be round or segmented.

NYM is the designation of an analogue of the Russian product brand VVGng, produced according to the German standard VDE 0250. The number of cores also varies from 2 to 5. The insulation material is the same polyvinyl chloride, which does not support combustion. The main design difference between this product and its Russian counterpart is the presence of an additional non-flammable seal between the core insulation and the outer sheath of the cable.

Device Features

• The outer sheath of the cable is made of polyvinyl chloride.
• Between the outer shell and the cores there is an intermediate layer of non-flammable sealant - chalk-filled rubber.
• Current-carrying conductors are insulated with polyvinyl chloride insulation.
• The number of cores can be from 1 to 5.
• The cores are made of copper and can consist of either one wire or several wires, depending on the cross-section.
• Color markings comply with international standards. According to domestic rules, the ground wire must have a yellow-green color. It is allowed to make the sheath of the ground wire pure green or yellow. Phase conductors can be painted in different colors.

Color coding

NYM cable produced in Russia or imported from Europe, if it is not a fake, always has color marking of conductor insulation that complies with the standards of Russian PUE (Electrical Installation Rules).

The colors of their internal insulation may vary depending on the number of cores.

1. Single-core - color is not regulated.
2. Twin-core type O - black and blue.
3. Three-core type O - black, brown and gray.
4. Four-wire type O - black, brown, gray, blue.
5. Three-core type J - black, blue, yellow-green.
6. Four-wire type J - black, brown, gray and yellow-green.
7. Five-core type J - black, brown, gray, blue and yellow-green.

By color marking you can easily determine the purpose of this particular cable. The conductor in the blue sheath is always zero in single-phase networks or neutral in three-phase networks. Yellow-green is a well-known designation for an “earth” conductor. All other colors indicate phases.

Please note: NYM cable, made in accordance with GOST 22483, which regulates the standards of such products, cannot have a conductor in white or white-blue insulation. If the wire you are embroidering contains a white core, this is a fake. You can use it only at your own peril and risk.

Decoding the NYM marking

The marking includes an alphanumeric designation that characterizes the cable parameters.

Consider them in more detail:

• N - indicates that this brand is manufactured in accordance with the German Normenleitung standard;
• Y - indicates the insulation material with which the cable cores are covered, in this case it is polyvinyl chloride or PVC for short;
• M – indicates the presence of an outer sheath in the cable, comes from the German Mantelleitung;
• J – indicates that the cable is equipped with a PE protective grounding conductor with a corresponding yellow-green color;
• O - indicates that the model contains a neutral conductor N with the corresponding blue color.

Consider an example of decoding the markings for the NYM – J – 3 × 2.5 cable. Here is a model with polyvinyl chloride cable insulation, which has a dedicated ground wire. In total, the cable contains three cores with a cross-section of 2.5 mm2 each. The arrangement of all elements inside the NYM cable is determined by its design features.

NYM-J cable design elements:

• Core: single-wire or multi-wire copper conductor.
• Insulation: polyvinyl chloride (PVC) plastic compound.

• Internal filling: unvulcanized rubber, highly filled plastic compound or thermoplastic elastomer.
• Outer shell: polyvinyl chloride plastic compound in grey, black or white.

The NYM-J cable uses internal filling made of unvulcanized rubber, highly filled plastic compound or thermoplastic elastomer, which:

• * prevents the risk of cracking during operation in unfavorable conditions,
• * allows you to easily and conveniently “cut” the cable during installation,
• * increases cable flexibility,
• *gives the cable a round shape.

Scope of application of NYM-J cable:

Used for installation of electrical wiring of cable lines:

• * In industrial, residential and public buildings
• * Can be used over, in and under plaster
• * In brickwork and concrete.
• * Outdoors, out of direct sunlight.
• * Laying can be carried out in pipes and channels.
• * The cables are designed for use in light conditions where there are no mechanical loads.

The service life of the NYM-J cable is 30 years. Total reviews: 0 – Write a review 0r.

NYM cable manufacturers

Well, the last thing I would like to talk about is which NYM manufacturer is better to choose. Among foreign manufacturing plants, the leaders are Helukabel, Lapp Kabel and TKD Kabel (Germany). Products from manufacturers DENIZLI CABLE LTD (Turkey) and Nexans (France) are also of high quality.

Among the domestic manufacturers of NYM cable, we can recommend such factories as Sevkabel, Kamkabel and Pskovkabel, whose products have passed all certificates of conformity and meet all TU and GOST standards.

We draw your attention to the fact that in recent years, counterfeits have begun to appear more and more on the market of electrical products. In your case, we strongly advise you to avoid products marked “NUM” and “HUM”, as in the photo below!

That's all I wanted to tell you about the technical characteristics of the NYM cable. Having studied the conductor markings, scope and purpose, you can now accurately decide whether to buy this product option for your own electrical installation work.

Main manufacturers

It should be noted that the distinctive quality of the NYM cable is ensured by an international standard, which is characteristic not only of German brands, but also of a number of domestic manufacturers. Of course, domestic samples are no worse, but have a more affordable price. Among domestic ones it is worth highlighting:

• "Sevkabel";
• "Concord";
• "Kamkabel";
• "Pskovkabel".

Among foreign manufacturers who have the appropriate certificates and supply their products to the domestic market, the following should be highlighted:

• Serbian "Novkabel AD"
• German “Lapp Kabel”, “Kabeltec”, “TKD Kabel”;
• French "Nexans";
• Turkish "DENIZLI CABLE LTD".

By purchasing NYM cable from these companies, you can be sure that it meets the stated parameters. If you come across a model from other manufacturers, then to identify a fake, pay attention to the markings. Companies that do not meet the standard try in every possible way to rename their products to the similar name NUM or HUM instead of NYM. This can be seen on the shell:

Rice. 4: Example of non-original markings

As you can see in the picture, the top cable has the original markings, but the other two differ from it. Therefore, it is impossible to guarantee the same technical characteristics for them.

Advantages of NUM cable

1. High elasticity. In principle, this is one of the reasons for the high popularity of the conductor. It is easy to install in hard-to-reach places.
2. Sufficiently high fire safety of operation. The NUM wire does not support combustion, but laying it in a bundle is still not recommended.
3. The characteristics described above allow the use of this type of electrical wiring in wooden buildings.
4. The color design of the cores meets the standards.

Advantages and disadvantages

Compared to other cable and wire products available on the domestic market, NYM cable has a number of significant advantages:

• Not afraid of moisture - in comparison with domestic models with vinyl insulation, NYM is much less susceptible to moisture absorption. Due to this, NYM can also be laid in wet areas (basements, wells, mines, etc.) without additional devices.
• Flexibility - easily changes geometric shape and can be laid in the most difficult to reach places, make turns, etc. This property is ensured by the intermediate layer.
• Does not support combustion - due to the composition of the intermediate layer, the insulation does not burn, but only melts when exposed to a flame or spark. This property allows NYM to be used in areas with increased fire hazard.
• It has a wide variety of design options , both in the number of cores and in their cross-section, due to which one such cable can provide full power supply in circuits with a different number of phases, wires and for any load.

It should be noted that an important factor in all the advantages of the NYM cable is the manufacturers’ compliance with the international standard. Which ensures higher quality products in all respects.

But, in addition to the above advantages, NYM also has some disadvantages. Firstly, the high quality of all NYM brand cables also determines their higher cost in comparison with domestic analogues, for example, the same VVGng. Secondly, NYM is not recommended for installation in areas where it may be exposed to sunlight. Since its insulation loses its characteristics from the sun, and the cable fails much faster.

Operating and installation conditions

• Operating temperature – from -50 to +50 °C;
• The minimum service life of the NYM cable under normal operating conditions is 30 years;
• The main areas of application are indoor and outdoor installations. Outdoor use is only possible outside of direct sunlight.
• It is possible to lay the cable on top of, in and under plaster in dry, damp and wet rooms, as well as in brickwork and concrete, with the exception of direct pressing into vibro-filled and stamped concrete.
• Installation can be carried out in pipes, in closed installation and curved channels; gasket temperature – not lower than -5 °C;
• The size of the mounting bends is at least 4 shell diameters.

Description and decoding of the NYM cable

NYM power wire is a cable product that is widely used in stationary power, as well as lighting industrial and household networks with voltages up to 0.66 kV at frequencies of 50 Hz.

Installation of
NYM power cable is possible both inside dry, damp, wet rooms, and in open space, subject to a sufficient level of protection from mechanical damage and solar ultraviolet radiation (in cable ducts, metal hoses or corrugated pipes).
It is permissible to lay the wire under or on top of plaster, in brickwork or in concrete. Direct pressing of the cable into stamped or vibration-filled concrete is strictly prohibited. Explanation of the NYM marking:

· N

– compliance with the German cable product classification standard Normenleitung,

· Y

– the insulating layer is made of polyvinyl chloride (PVC plastic),

· M

– installation in different conditions is possible.

Additionally, the VDE mark must be present on the wire insulation, which indicates that the cable is manufactured according to the German industry standard Veiband Deutscher Electrotechniker 0250 and is approved for use in areas with an increased risk of fire, for example, in wooden buildings.

KG – designed for harsh conditions

Perhaps the best solution for outdoor use is a cable marked KG. It has an insulating layer of rubber based on natural rubber. Moreover, such insulation is used both outside and for the cores themselves. This helps the product maintain high flexibility even in severe frost, and also makes it resistant to ultraviolet radiation - the shell does not crack. Withstands high air humidity. It is suitable for outdoor lighting of cottages, private houses, and enterprises. Can be used in car washes and production areas. It is often the basis for creating extension cords and powering equipment.

Understanding the labeling

• K – cable
• G – flexible

It has copper cores - from 1 to 5 pieces. The cross section can be up to 95 square meters. mm. For example, the 3x4 marking means that the cable is three-core and the cross-section of the cores is 4 square meters. mm. There are also additional letter designations: t – the cable is suitable for tropical zones and rooms with air humidity up to 98%; n – non-flammable with oil-resistant insulation; chl – resistant to cold, withstands frosts down to -60 °C.

What errors occur when using NYM cable

NYM wire is mainly recommended for installation work in buildings in the construction of which wood or flammable materials were used.

It must be remembered that the wire does not spread fire only when individually laid. If you need to use a group gasket, then it is advisable to purchase products from other brands that are intended for this type of work.

Many people are faced with the problem of laying wires in baths, saunas or steam rooms. It is allowed to install this wire in such premises. Because the rubber layer fits tightly to the wire insulation, thereby preventing moisture from penetrating into the cable. These are the only problems that may arise when using the product.

The better NYM

• increased elasticity - easier wire laying, reducing installation time for long or complex electrical routes;
• the presence of an intermediate layer - seals the electrical conductors and simplifies the pre-assembly cutting of the product;
• properties of the material of the insulating layer and shell - does not support the spread of fire when installed alone or installed in a group;
• ideal quality - manifested, for example, in 100% identicalness of the actual cross-section of conductors and sheaths to the indicators specified in the technical documentation for the wire;
• impeccable reputation in the professional environment - many experts recommend using NYM in projects permitted by standards.

Classification and price

Cables are available with different numbers of cores. Their number is from 1 to 5. Some enterprises produce products with the number of cores up to 7. The wire also differs in the cross-sectional area of ​​the conductors, ranging from 1.5 to 6 square meters. mm.

The level of prices depends on the characteristics of the cable and the pricing policy of the selling company. The cost ranges from 20 to 500 rubles per linear meter, taking into account the characteristics of the wire and the above conditions. By purchasing products in bulk, the client can receive a discount.

Design

To better understand the design of the NYM cable, let's look at its design using a specific example.

Rice. 1: NYM cable design

As you can see in the figure, this brand has the following arrangement of elements:

• 1 – current-carrying core, which is made of copper, their number depends on the specific NYM cable model and can vary from 1 to 5 conductors, some factories can find models with 7 conductors. The cross-section of the cores can vary from 1.5 mm2 to 35 mm2, each of the cores is equivalent in size. With a cross-sectional area of ​​up to 10 mm2 inclusive, the core is made as a monolithic conductor. And from 16 mm2 and more it is made of several twisted wires.
• 2 – conductor insulation, made of polyvinyl chloride and characterized by different colors, depending on the purpose of each of the cores. The specific markings for each type are shown in the table below:

Table: color coding of cable cores

• 3 - sealing layer, made of non-vulcanized chalk-filled rubber, provides additional insulation and prevents the penetration of moisture from the outside. Due to this filler, the NYM cable maintains its round shape and is also not subject to combustion.
• 4 – outer shell, made of sheet plastic and designed to protect against mechanical influences and aggressive substances. Its boundaries determine the total cross-sectional area of ​​the NYM, which depends both on the number of cores and on the size of the insulation on the wires and in the intermediate layer. This parameter affects the possibility of placement in niches, voids, trays, etc. The cross-sectional area of ​​the cable is not always constant, but approximate dimensions can be determined from the table:

Table: geometric parameters of elements of some NYM cables

VVG – a safe solution for residential premises

If you ask electricians what is the most common type of cable for residential buildings, they will answer - VVG. This is the most popular solution for internal electrical networks and closed electrical installations with voltages up to 1 kV. The maximum service life is 30 years. This type of cable replaced PVS as more reliable. But at the same time, this is one of the most budget options on the market, which is why it is in such great demand.

Understanding the labeling

• B – PVC core insulation
• B – PVC outer sheath
• D – there is no external armor or other additional protective layers

It uses copper cores, which can be from 2 to 5 pieces. The manufacturer also indicates the cross section. For example, 3x2.5 indicates the presence of three cores and a cross-section of 2.5 square meters. mm.

There are several varieties in this category of electrical products:

• VVGng - does not propagate combustion due to special additives in the insulating layer; several cables can be laid in one channel without additional protection of each with corrugation;
• VVGng-ls is a non-flammable cable that produces a low amount of smoke when melted, therefore ideal for residential premises;
• VVGng-frls is perhaps the safest cable in this category, as it does not support combustion, has a low level of smoke generation, is resistant to high temperatures and even open fire, all thanks to additional mica insulation.

NYM – confidence for many years

This is a German analogue of the VVG cable. Only it is manufactured in accordance with the German standard DIN VDE Normenleitung. It is characterized by high reliability, safety and long service life - up to 40 years. It is most often chosen for installation in apartments, cottages, office buildings, commercial and industrial premises. Many manufacturers offer frost-resistant cables, the operating temperature of which can reach -50 °C. Therefore they are suitable for installation in unheated rooms.

Also, the NYM sheath is not afraid of ultraviolet radiation, unlike VVG - you can install the cable where direct sunlight hits. It is also easy to cut without special tools, which electricians appreciate.

Understanding the labeling

• N (normenleitung) – manufactured according to VDE standard
• Y (ysolationsschicht) – polyvinyl chloride insulation
• M (mantelleitung) – there is an outer shell

This type of cable can have from 1 to 7 copper cores. The cross section can reach 6 square meters. mm. You can find a product marked ls (low smoke), which means reduced smoke production when heated. The letter J indicates the presence of a yellow-green protective ground conductor. If there is no letter after the name or there is the letter O, this means there is no grounding conductor.

Application

NYM cable is used as a device for transmitting electrical energy in power circuits. This brand has become widespread in the power supply of both household and industrial facilities. Due to its varied design, it can be installed for single-phase and three-phase circuits, both with and without a dedicated grounding or neutral conductor.

Rice. 3. NYM application for single-phase and three-phase consumers

NYM is used for the manufacture of wiring, both internal and external. In the first case, laying in the walls is carried out in a standard way without the need to use additional devices. External fastening is also carried out on open sections of walls, but unlike other brands of cable and wire products, it does not require additional protection and insulation using the same cable channels, corrugations, etc., since the number of dielectric layers already provides a sufficient level isolation. Exceptions for outdoor installation are walls made of flammable material and those areas where NYM is exposed to direct sunlight and must be protected from ultraviolet radiation.

NYM cable is also used to connect powerful equipment and power units. For this, both two-wire and more branched options are selected, depending on the type of load. As an example, it can be used to make an extension cord to power a power tool during construction work. Since the NYM insulation level is more than enough for any class of power tool.

It can be installed as a current-carrying element in fire and explosion hazardous areas of any objects. Where installation of other types of cable and wire products is not permitted.

What is the difference between NYM and VVGng

The NYM cable will be useful only for single installations. If you are planning a group session, then it is better to make a choice in favor of VVG. Structurally, both products consist of several copper cores with polyvinyl chloride insulation and the same outer shell. However, only VVGng (the prefix “ng” indicates the non-flammability of the cable) is able to stop the flame and prevent its spread during group installation of several conductors.

We list the main technical and operational characteristics of NYM and VVGng and compare them in the table below:

NYM cable most common questions, errors and misconceptions

Home / Reference materials / NYM cable most common questions, errors and misconceptions

In this article we will try to answer all the most common questions that may arise for anyone who wants to purchase an NYM cable. We will also try to dispel all misconceptions that relate to this cable.

1) The most frequently asked question: “Is it possible to use NYM cable for installation in apartments and residential premises?”

Answer: Yes, the NYM cable can be used in installing apartment wiring; you can also use VVG or VVG flat. Installation is possible both along a groove and in a cable channel. But in case of group installation, use VVGng(A) or VVGng(A) LS cable. If increased fire safety requirements are applied in the room, use VVGng(A)FRLS or VVGng(A)LSLTx cable.

2) “NYM gasket in a metal hose yes or no?”

Answer: Based on the standards, the NYM cable is not made as a single-core cable, so laying a cable with 2 or more cores is possible through a metal hose or a metal-plastic pipe.

3) “Is there an analogue of the NYM cable with a large number of cores?”

Answer: According to GOST-R, NYM power cable is manufactured in 2, 3, 4 and 5-core versions. If the number of cores required during installation exceeds five, then use cables with KVVGng LS or KGVVng LS filling.

4) “In everyday life, VVGng and NYM cables are considered identical. Is it true?"

Answer: This question is best answered by the comparative table below:

5) “What are the differences between NYM according to the German VDE standard and the many NYM cables according to specifications that have flooded the Russian market?”

Answer: The main visual difference is in the markings that are applied to the surface of the NYM cable. Accordingly, the presence of the VDE mark on the cable gives grounds to consider it manufactured under a license using German technology. The absence of such marking means that the cable is manufactured according to specifications (technical conditions). Manufacturers who produce cables according to VDE are “GK Sevkabel” and “Electrokabel”. The remaining differences relate to the cable structure, which are prescribed for TU cables in GOST 23286. GOST 23286 indicates the established thickness of the insulation and core and the minimum value level for the thickness of the insulation and copper power core. And the VDE standard establishes an average value for the thickness of the insulation and core, which the cable must fully comply with, that is, there are no deviations in manufacturing.

Just look at the example below and you will immediately understand everything.

6) “Problems arose after installing the NYM cable in the apartment. The cable releases an oily liquid and the outer sheath cracks. Is this a marriage? And is it worth continuing to operate?”

Answer: The cable market, in particular NYM cables, is oversaturated with various low-quality products. Including various variations on the NYM cable - these are NUM, NUM, NUM, NUMng and others.

The above case is standard for low-quality products according to specifications or without any accompanying documents at all. A clear case of non-compliance with standards during cable production; most likely the problem lies in non-compliance with the ingredient components in the cable insulation. Usually the cable is purchased on the construction market, although sometimes large construction hypermarkets are guilty of this.

In such a situation, “the miser pays twice.” Because cable according to specifications is cheaper, but with it there is a risk of encountering such a problem. Which will lead to a complete replacement of all wiring. Cheaper does not mean better; for cable this axiom is squared.

But it’s worth repeating mistakes, buy a proven NYM Sevcable cable made according to the German VDE standard or a proven NYM cable

Answer: Laying is possible only in a single gasket. In this case, everything will comply with fire safety requirements. But if you want to use a cable channel for several types of cable, then use VVGng(A) or VVGng(A)LS.

“At my summer cottage I plan to provide lighting for the entire area. I was thinking about running the NYM cable in a corrugated pipe in a trench. Is it possible to do this? Or do you recommend other protective materials?

Answer: In this case, regulations strongly do not recommend using a cable in a non-armored sheath. That is, by replacing the NYM cable with VBBShV or VBBShVng, you will thus avoid problems in future operation.

9) “In a construction hypermarket I came across two types of NYM cable. One was marked NYM-J and the other NYM-O. Are there any significant differences?

Answer: The only significant difference is the marking of the grounding conductor in the NYM-J cable in yellow-green color. NYM-O there is no grounding conductor and the neutral conductor is highlighted in blue.

10) “Can I use NYM in a room with high humidity and high average temperature? I am planning wiring in a bathhouse made of a wooden frame.

Answer : Installation standards do not prohibit the use of NYM cable in damp and warm rooms. The only caveat is that the temperature should not exceed + 50 degrees Celsius, which may be difficult to do if YOU run the cable openly in a steam room.

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What to consider when choosing a cable

Within each described category there are subtypes, and you have probably already decided on the most suitable cable for your requirements. But there are also general tips that guide your purchase.

• First, consider the voltage. In a household network its value is 220 - 230 V, in an industrial network - 380 V and higher. Here you will find a cable for both needs. The main thing is to pay attention to the number of cores.
• Secondly, calculate the cross section. It depends on the type of gasket - open or closed, current strength and connected power. If you do not know these parameters, it is better to contact an electrician. And according to his calculations, order the required cable.
• Thirdly, pay attention to which document the cable is made from. In Russia this may be TU or GOST. If the installation will take place at an enterprise where the parameters of the electrical network are strictly controlled, it makes sense to give preference to GOST.
• Fourthly, calculate the length and decide how it will be more convenient to buy the required quantity. Manufacturers offer cable in a coil, coiled, on a reel and cut to individual lengths.
• Fifth, consider the country of production. You can purchase products from China, Russia, Europe and the USA. Products differ in price, workmanship and warranty.

If you need advice on selection, please contact our managers. They will help you choose the right cable and guide you through the parameters.

Available methods for quality control of NYM cables

Control methods are presented that, while not strictly complying with the DIN standard, allow making preliminary conclusions about the quality of the cable if the measured values ​​differ significantly from the regulated ones. The final conclusion about the compliance of the cable with the standard can be made only after testing the cable in a specialized laboratory using strict methods and in the volumes specified in the standard.

Visual inspection The following can be checked: the number and color of the cores, the number of wires in the core, the integrity of the insulation, filling and sheath and the ease (without damage) of their separation.

Measurement of structural dimensions Can be checked using suitable measuring instruments: insulation thickness, infill and shell walls, and outer diameter. Measuring the diameter of the wires dpr and calculating the cross-section of the core using the formula 0.785dpr2N (where N is the number of wires in the core) is not a strict method for controlling the cross-section of the cores, because confirmation of cross-section compliance is electrical resistance, however, a significant deviation of the calculated cross-section from the nominal (more than 10%) may serve as a basis for doubts about the quality.

Measurement of the electrical resistance of current-carrying conductors Can be carried out on a finished cable with an ohmmeter with a suitable measurement limit (for cables with a small cross-section at a normal length in a coil or on a drum, it can be several Ohms) and recalculated for a length of 1 km. If the cable has twisted cores, the obtained values ​​should be reduced by 1.02 times. Particular attention should be paid to making good contact with the test leads.