Good electricians, when laying electrical wiring, use a reliable and durable (the manufacturer's declared service life is at least 30 years) VVG cable. Most often it is VVGng, which has insulation that is not very susceptible to combustion, but this is not so important. And many modern specialists prefer to abandon the usual VVG and try to lay NYM cable, which in its technical characteristics is very similar to VVG. But why is he so good? Need to figure it out ...
Specifications NYM
Before comparing NYM with VVG, you need to consider its technical characteristics, and do it scrupulously:
- The maximum allowable voltage is 660 V. The cable is suitable for both single-phase (220 V) and three-phase (380 V) networks.
- The number of cores is from 2 to 5.
- The service life is not less than 30 years with correct laying and connection.
- Working ambient temperature - from -50 С0 to +50 С0.
- The thickness of the insulating layer is from 0.6 to 0.8 mm.
- The thickness of the protective cambric is 1.4 or 1.6 mm.
The indicators are quite similar to VVG, but what is the difference between NYM and why do almost all experienced craftsmen prefer to use it in their work?
The main differences between NYM and VVG
- Firstly, this is the thickness of the outer protective layer, or as they say “in a simple way” - cambric. Even 1.4 mm is quite a solid indicator, which means that the cable is quite resistant to mechanical damage, since such a protective coating is quite difficult to break through even on purpose, not to mention accidents.
- Secondly, it is absolutely incombustibility. Provides this quality of the material of the intermediate layer (between the cambric and the direct insulation of the conductors) - special rubber with chalk filling, which does not lend itself to vulcanization, which only enhances its fireproof properties. Also, due to the presence of a similar material in the structure, NYM cable can be laid in rooms with high humidity.
3. Thirdly, it is a perfectly round shape, which is an exceptional advantage for laying. The flat VVG provides a ton of time, especially when cornering, while the NYM is really fun and easy to work with! And when unpacking it takes much less time, which is also important.
Some features of NYM mounting
The cable is easy to use, but still requires a certain approach and the necessary tools at hand. For example, a good fitter's knife, always with a new sharp blade! The protective and intermediate layer are strong enough and you will need to “fill your hand” to quickly remove them. Or use a stripper specially designed for this.
It should also be remembered that the NYM bend radius when turning the cable should not be less than 4 outer diameters of the product. Otherwise, its characteristics declared by the manufacturer deteriorate sharply and the service life will no longer be 30 years, but much less. If you follow all the installation instructions exactly, then NYM will serve for a long time and reliably - it has been checked more than once.