For industrial and domestic purposes, NYM cable is increasingly being used to create power and lighting power networks. This is a high-quality German product that comes from Europe and is also produced in Russia. The closest domestic analogue is the VVG cable.
This cable is manufactured according to German technologies and is characterized by the presence of copper conductors and high-quality plastic insulation that does not support combustion.
Decryption
The range of wire and cable products is extremely large. Therefore, special markings are used for systematization. In the case of a NYM cable, the decoding of each letter will be as follows:
- N is the mark of the German standard (Normenleitung), indicating that the product has passed a series of checks and in its parameters corresponds to the declared characteristics. Complete with NYM power cable there is always a certificate of compliance with international quality standards.
- Y means polyvinyl chloride (PVC) is used for the insulation. A feature of this material is moisture resistance and lack of reaction with acids, alcohols, gasoline, and various gases.
- M means the presence of a protective shell designed for small deformations. What makes NYM electrical cable suitable for installation work.
The shell may contain the inscription VDE. It is an abbreviation for the German Electrical Engineering Association (Verband Deutscher Elektrotechniker). The VDE marking informs that the sheath does not support combustion, that it can be used in fire hazardous areas and that the product complies with all international standards.
The marking of the NYM electrical cable depends on the presence of grounding and may contain the symbol J or O. At the same time, the O symbol may not be indicated in the marking, since it only informs about the absence of a wire intended for grounding. The symbol J indicates the presence of such a conductor, therefore it is always indicated.
The NYM-J cable is characterized by a green/yellow protective earth conductor. Filling can be from thermoplastic elastomer, unvulcanized rubber or highly filled plastic compound. Such insulation eliminates the formation of cracks during operation, increases flexibility, and gives the correct round shape.
Coolant addition may be added to the marking. It means that the conductors used are single-wire, which means they are less flexible than multi-wire ones.
Thus, the manufacturer puts all the necessary information into the name of the NYM wire, the description of which contains information about the properties of the sheath, the number of cores and the cross section.
For example, marking NYM-J 3x3.5-0.88 means that this is a standard electrical cable with an outer sheath made of PVC, three cores with a cross section of 3.5 mm² for a voltage of 0.88 kV and grounding.
Areas of use
According to the marking, NUM wires are recommended to be used exclusively for internal single fixed laying. Without additional protection, laying in a bundle is prohibited.
Outdoor use of the cable is not recommended due to the fact that PVC is degraded by the ultraviolet radiation present in sunlight. If it is necessary to stretch the wire outdoors, it should be enclosed in a steel or plastic box. It is also not recommended to lay the wire in fresh concrete.
Installation is regulated by the manufacturer's recommendations and electrical and fire safety standards. The use of such electrical cables is possible in any electrical work. Even in buildings with the first class of electrical safety protection and in explosive zones V1b, V1g, VPa.
NYM is used for laying under plaster, in concrete masonry, in wall panel channels, in specialized pipes and ducts.
There are a number of restrictions for use in natural wood houses. Open laying is carried out only in pipes and ducts, and inside wooden walls, laying is possible only in metal pipes.
NYM cable design
The conductor in the cable is made exclusively of copper and can be single-wire or stranded. It is covered with PVC plastic in various colors in accordance with existing standards.
The possible number of cores is from 1 to 5. The number depends on the cross section of the conductors.
The intermediate insulation of the cable consists of a mixture of rubber and chalk. It performs the function of a dielectric and does not support combustion.
The outer shell is made of durable, flame retardant, light gray PVC plastic.
NYM Cable Specifications
International standards define the following specifications:
- Temperature range: -50…+50°C.
- Laying temperature: min. -5°C.
- Bending radius limitation: minimum 4 diameters.
- Warranty period: 5 years.
- Service life: up to 30 years.
- Cross section range of copper conductors: 1.5 - 35 mm².
The electric cable can be manufactured: according to German standards, GOST, TU. The manufacturer determines the technical conditions himself. For this reason, some NYM cable manufacturers may have different specifications from the standard.
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