Review of technical characteristics and manufacturers of NYM cable

NYM copper cable is a popular conductor used in the construction of internal wiring of residential and administrative buildings. It can be installed inside many other buildings, including mid-level fire-hazardous structures.

The product originally appeared in Europe, hence the Latin letters in the abbreviation. Today, the product is manufactured in many European countries and in several Russian factories. Cable products from Sevkabel and Pskovkabel are in no way inferior in quality to imported NYM products.

Application area

NYM cable can be used in various climatic zones, inside production facilities with low or high humidity levels, in domestic and living rooms and even outdoors. When installing outdoors, it is important to avoid direct exposure to ultraviolet rays of the sun.

Inside residential buildings, wire is used in different cases: both with open and hidden wiring. It is used to switch lighting equipment, electrical sockets, switches and other devices. When installing a line in open ground, the cable must be protected using corrugated pipes or special boxes. When laid aerially, NYM is reinforced with high-quality overpasses. For any electrical devices that require a seal at the input, it is best to use just such a cable.

Scope of cable application

NYM cable is mainly used in various electrical installation works, no matter in the domestic or industrial sphere. This type of wire is mainly used for laying electrical wiring in rooms made of wood, because the cable design includes a special sheath that prevents the spread of fire.

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Cable marking

Quite often it is used for installation outdoors, but on condition that direct ultraviolet rays do not reach the wire. For installation in a residential area, NYM multi-core wire is usually installed in a hidden way. This cable is used when connecting lighting groups or sockets. One of the advantages of the wire is that the conductor can also be used for installation in the soil, but it is recommended to place the product in a corrugation, thereby making it safe.

Explanation of the abbreviation NYM

The Latin abbreviation NYM stands for the following:

• N – standard type cable (German gradation);
• Y – the insulating sheath of the cores is made of polyvinyl chloride (PVC);
• M – with outer shell.

As usual, the absence of the letter “A” in the first place indicates that the cable cores are made of copper. In addition to the three standard letters in the designation, J or O can be added through a hyphen - with or without a yellow-green conductor (ground conductor).

After the alphabetic symbols there are necessarily digital symbols, indicating the number of cores and the cross-section of each of them. For example, the product NYM-O 4×4.5 - 0.66 can be deciphered as follows:

• standard cable with polyvinyl chloride core insulation and outer sheath;
• consists of four cores with a cross-sectional area of ​​4.5 square meters. mm each;
• used at voltages up to 0.66 kV (660 V).

Color coding

Such a cable must be produced with standardized color markings. The absence of this indicates that the product is not certified and is a counterfeit. The standards for the color of conductors are prescribed in the rules for electrical installations (PUE).

The set of colors varies depending on the exact number of cores located inside the outer sheath:

• there are no regulations for single-core cables;
• two conductors without a grounding cable - black and blue conductors;
• three cores without a grounding cable - black, brown and gray;
• four cores without a grounding cable - black, brown, gray and blue;
• three cores with a grounding cable - black, blue and yellow-green;
• four cores with a grounding cable - black, brown, gray and yellow-green;
• five cores with a grounding cable - black, brown, grey, blue and yellow-green.

Depending on the color marking, specialists can easily determine the main purpose of the cable. The blue wire is usually used to connect the neutral wire in single-phase networks. In three-phase, the blue core acts as a neutral. The yellow-green conductor in all cases serves as a grounding conductor.

Important! In accordance with GOST, the NYM cable should not contain conductors with white or white-blue insulation. If there is one, the conclusion is simple - it is a fake. Further use of such products, if possible, is at your own peril and risk.

NYM cable: operational and technical characteristics

This is a universal conductor used for installing sockets and lighting. Technical characteristics make it possible to equally use it in production and when laying home wiring, which determines the high demand for products with this marking. The abbreviation in the cable name displays basic information regarding its application:

• N – this letter indicates the product’s compliance with basic European standards.
• Y – wire insulation is made of PVC.
• M – denotes no special restrictions on use, i.e. This wire is not intended for any one type of electrical installation work.

The standard by which it is manufactured was developed in Germany, but its main provisions quickly spread to European countries and the CIS countries, where it is manufactured in many factories, albeit according to slightly modified specifications.

NYM cable design features

Copper conductor is used to make cores. If its cross-section is from 1 to 10 mm², then the wire is single, and for cables from 16 to 35 mm², cores are made, twisted from several conductors.

Insulation and internal filling differ somewhat depending on the number of cable cores. When there are 4-5 of them, there is a PVC cord in the center of the wire, which prevents the conductors from moving. If there are 2-3 wires, then there is no need for it. In all cases, the NYM wire has three layers of insulation:

1. polyvinyl chloride separately on each core;
2. chalk-containing rubber is pressed into the empty space between the wires;
3. The outside is covered with PVC plastic coating.

These wires are produced in two modifications, differing in the colors of the core insulation - for use in electrical circuits with and without grounding - they differ from each other by the use of the letters J or O on the external insulation.

• In the first case, the cable is marked as NYM-J, which indicates the presence of at least three cores, one of which is yellow-green in color.
• In the second case, the NYM-O marking is used, indicating that there is no yellow-green wire, but there is a blue wire for the neutral conductor.

The number of cores in NYM cables can be from two to five, and their colors are as follows: black, blue (NYM-O), yellow-green (NYM-J), brown.

Main characteristics

For NYM cable, the main technical characteristics determine the scope of use:

1. Maximum voltage up to 660 Volts.
2. Number of cores – 2-5.
3. The permitted temperature of use (at which there are no noticeable deviations in the properties of the cable) is from -50 to +50 C°. Can withstand prolonged heating up to +70.
4. The permitted installation temperature is higher than -5 C°. If the wire must be laid at a temperature below the specified temperature, then the installation site and the wire itself must be heated - otherwise damage to the sheath is inevitable.
5. High elasticity – bending radius during installation from four outer diameters.
6. The maximum humidity at which the wire can be located is 98% (it cannot be laid under water).
7. Restrictions on use - it is prohibited to use the NUM cable for laying underground, and when used outdoors, it is necessary to hide it in corrugation, since PVC insulation is destroyed over time by exposure to ultraviolet radiation.
8. Factory packaging - coils of 50 or 100 meters, reels of 500 meters.
9. The estimated period of operation under normal conditions is 30 years.
10. The warranty period from the manufacturer is 5 years.

For more information about the cable characteristics, watch this video:

and here you can see the flammability tests of the NYM cable in comparison with the VVGng-LS cable:

and comparison of cables from different manufacturers:

Differences in technical characteristics: VDE vs TU

Specifications may vary somewhat depending on the manufacturer. Wires manufactured in German factories are manufactured according to the VDE standard and are approximately the same in all cases. In the CIS countries, manufacturers are guided by local technical conditions (TU), so not only the properties of the cable are different, but also its marking.

Local manufacturers can save money by at least using filler, which is pressed into the space between the cores. In original cables it is chalk-filled rubber that does not support combustion, but in domestic ones another material may be used. As a result, original cables can be used even if there is minor damage, but in this case it is better not to use domestic cables.

It should be borne in mind that making electrical wires in makeshift conditions is a rather thankless task - whatever one may say, the wire requires copper or aluminum, since there is nothing special to save on here. As a result, all products of this kind are usually certified and if you look closely at the markings, it is quite easy to distinguish the original from local products, at least by the markings - German wires must have the letters VDE and NYM on them. If they are not there, then there is a domestic cable on the counter.

Additionally, it doesn’t hurt to look at the material filling the space between the cores - if there are drips there, then this is a reason to doubt the use of chalk-filled rubber, which should be used according to original standards.

Design features

Domestic manufacturers produce several modifications of the NYM cable. Some of them are designed in full compliance with German standards and requirements (VDE), others are designed according to customer specifications. In most cases, each plant uses its own developments, prescribed in the technical specifications, and the cable can be called differently - from NUM or NUM to NUM. This suggests that there is no strict general standard here. As a result, you can buy what appears to be NYM on the market, but in fact purchase domestic analogues, the technical and operational characteristics of which differ significantly from German standards.

An example of inconsistencies include leaks of the compound used when filling the free space between the cores. German engineers require the use of a compound made of chalk-filled rubber, but the specifications of domestic manufacturers may indicate a different material characterized by less strength and a weak thermal coefficient. This leads to the appearance of various leaks.

The NYM wire can use a monolithic core structure, the cross-sectional area of ​​which should not exceed 10 square meters. mm or stranded. Many people mistakenly call a multi-core cable, but in reality we are talking about the structure of one specific core. The cross-section of stranded conductors is in the range of 16-35 square meters. mm.

Thus, the NYM cable consists of several copper cores insulated with polyvinyl chloride plastic. All conductors are covered with a non-flammable layer, on top of which an external insulation made of polyvinyl chloride is placed. In accordance with GOST, each wire has a specific color marking.

Specifications

Let us briefly list all the technical and operational parameters of NYM:

• number of cores - from two to five;
• maximum permissible voltage - 660 V at an alternating current frequency of 50 Hz;
• flexible cable;
• no need to heat up during installation;
• The gasket is permissible at a minimum temperature of -5 degrees. Celsius;
• operating temperature range from -50 to +50 degrees. Celsius;
• service life – 40 years;
• permissible bending radius - four outer diameters;
• Resistant to open fire, does not spread fire.

Advantages and disadvantages

Among many conductors, NYM cable is considered to be the “golden mean”. To better understand its quality, let’s consider the main advantages of this product:

1. Increased elasticity, ease of installation and operation. This flexibility is due to the presence of an internal insulating layer of rubber. This advantage is very important when performing any installation work on electrical wiring, as well as when installing equipment in inaccessible or hard-to-reach places. The wire is not affected by dampness and moisture, so it can be laid along the ground over long distances.
2. If we talk about NYM, manufactured according to German quality standards, then before entering the market it must undergo numerous studies and tests. The Germans have long earned the title of the most reliable and high-quality manufacturers of industrial and other products, so there is no doubt about the integrity of the insulation and the compliance of the cable with all the declared technical and operational properties.
3. The product does not support combustion, which was made possible due to the choice of material for the inner layer.
4. Most specialists and electricians recommend using the product to connect lighting systems and power circuits.
5. Long service life spanning several decades.

The most obvious disadvantage of NYM cable is its high cost. There are many domestic analogues, albeit with worse characteristics, the prices of which are several times lower.

NYM Wire Laying Rules

When laying, it is necessary to install the power line in a place where the sun's rays do not reach and where temperatures are critically low. The NYM cable must be laid in a place protected from contact with children or animals. If treated with care, the cable will last its entire lifespan.

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Gasket in the wall

When laying in wooden houses, it is recommended to install protective corrugation so that in the event of a fire the combustion does not spread to the building. When installing in the ground, it is necessary to install cable channels that will protect the product from excess load.

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 design

The NYM cable structurally consists of:

1. 2-5 pcs. twisted single- or multi-wire electrical cores;
2. an intermediate layer-sheath, obtained by extrusion from unvulcanized rubber material, placed on top of the conductors and filling the empty space between them, giving the product a round shape;
3. insulating layer made of polymer PVC, non-flammable, color-coded;
4. outer protective shell made of polymer PVC with self-extinguishing properties.

Manufacturers NYM

NYM cable is produced at foreign and domestic enterprises. The most popular factories in our country are:

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

Any products of these enterprises undergo all necessary stages of certification in accordance with international quality standards. For foreign companies, we will highlight the German TKD Kabel, Lapp Kabel and Helukabel, the French Nexans and the Turkish Denizli Cable.

NYM is stored and transported in special coils or drums, the diameter of which can be eight times the thickness of the cable itself. During storage, it is better to use a hard-to-reach and closed place, the minimum temperature of which is not lower than -15 degrees. Celsius. Also be sure to avoid direct exposure to direct sunlight.

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”

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Cable laying features

Despite the fact that the technical documentation states that the NYM wire is non-flammable, it would be a mistake to believe that it is absolutely not susceptible to fire. The main condition for non-flammability is the absence of bundles and other cables laid nearby.

Another feature of this brand of cable is its sensitivity to ultraviolet radiation, so it cannot be used in open spaces. On the other hand, the above VVGng has identical parameters and a much wider scope of application. It is suitable for both indoor and outdoor installations. VVGng can be safely used to enter an electric line from a pole to a house or when arranging a branch directly behind the SIP wire.

That is why many experts consider VVGng an improved analogue of the NYM cable. The foreign analogue is considered to be the MMJ wire, which is devoid of the above disadvantage. This is what is used for external installation.

Pros and cons of using NYM cable

At this time, such production is a kind of “golden mean” on the market among a similar group of products. Below are the main benefits worth highlighting:

• Elasticity and ease of use of the product. All this was made possible thanks to the rubber-based inner layer, which makes the cable itself quite flexible, elastic and pliable for this type of work. This advantage should be used in installation work of various types of electrical wiring in inaccessible or hard-to-reach places. Also, if you have to lay an electrical line at a fairly significant distance, then the cable is not afraid of the ground and dampness.
• Product quality. Before reaching the consumer market, a product undergoes a large number of studies and tests, including in foreign centers. So, when purchasing a product of this type, you can not hesitate and be convinced that the insulation, its reliability, and the cross-section of the cores comply with accepted standards and are clearly indicated in the marked code.
• The cable product is absolutely non-flammable. All thanks to the same inner layer. Therefore, it is often used in conditions that are fire hazardous.
• The product has many flattering and positive reviews from experts in the field of electrical installation. But if you look through the forums, the overwhelming majority of recommendations talk about the advantages of the cable when used for lighting purposes and power circuits.
• Long service life.

The advantages of the product speak for themselves. Perhaps the worst drawback is the price of the product. Compared to more affordable products from domestic manufacturers, you will have to pay a larger amount for such a cable.

Standard cable diagram. This is what a similar original product looks like.

Tips for choosing

When going to the market for such a cable, be careful, since most of the products that sellers call the domestic analogue of NYM wire are fake. This is evidenced by the lack of necessary markings. When choosing a cable, pay attention to the logo and markings shown. Reliable and trusted manufacturers always put their own markings on the product. This already provides some kind of guarantee that the manufacturer is not afraid to bear responsibility for the products produced and is confident in their quality.

Sales consultants or ordinary market traders may recommend that you purchase SHVVP or PVS wires, stating that they are an excellent analogue of the NYM cable. You should not fall for such tricks, since in the case of SHVVP and PVS we are talking about ordinary cords. The main characteristic that distinguishes a cord from a cable product is related to its operational capabilities. The first is often suitable exclusively for switching household appliances and equipment, and the second is for connecting all wiring and more complex equipment.

Be sure to choose a cable with a grounding, yellow-green conductor, which will allow you to ensure high safety when operating equipment and home wiring. When choosing a product cross-section, you need to be guided by simple and general rules. When connecting lighting systems, it is enough to use wires with a cross-section of 1.5 square meters. mm, socket or switches - 2.5, oven or electric oven - from 4.5 sq. mm.

Despite the numerous domestic factories that are trying to produce high-quality NYM cable, in this case it is best to give preference to foreign factories from Germany, France or Turkey. Who knows, perhaps in a few years the situation will change, but for now we are forced to state this sad fact. In terms of operation, NYM is only suitable for internal single gasket applications. The product does not support any other options: you should not be fooled by the persuasion and deception of sellers!

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.