Often among ordinary people in colloquial speech there is an interchangeability of two terms - “wire” and “cable”. These words are used as synonyms for each other. But this is not entirely true. Since these two concepts in a professional environment denote similar but different products used to move electric current from a source, such as a socket, to a device in which some process is performed under the action of electricity, for example, heating an iron or air conditioning a room.
What is wire and cable? Key Features
The word "wire" refers to a solid metal core or from several thin wires, (in other words, a conductive core), wrapped in a single-layer insulation. A conductor is also inserted into the middle of the cable - one or more. The presence of one core will indicate that the cable is single-core. Respectively,A cable with multiple cores is called stranded. The main difference between a cable and a wire is the multi-layered protective sheath.
To protect cables and wires from the action of moisture, acids, gases, wind, sun, materials from non-combustible rubber, aluminum, corrugated steel, plastic, lead grade not lower than C-3 are used. The lead content in the sheath must be at least 99.9%. For protection from aluminum, metal of a grade not lower than A1 is used with its content of at least 99.97%. The rubber layers of the protective sheath must be oil and petrol resistant and non-flammable. High-strength PVC plastic - non-flammable and vibration-resistant. Production standards determine the thickness of the protective layers, which depends primarily on the purpose, then on the structure and diameter of the cable. Cables can be laid in the ground, in sewer lines, in water. The protective layer of the cable can be sealed.
Inside the single-core coaxial cable is a copper, aluminum or steel wire, which is the center conductor. In some designs, it can be wrapped around a dielectric in the form of a fluoroplastic tape in some cases, a protective screen made of foil or bundles of thin metal wires is braided around it, then, as an option, a corrugated tube is put on. The extreme insulating layer is most often made of thickened polyethylene undergoing additional processing in order to protect against external negative factors (for example, ultraviolet radiation).
Single coreshielded and twisted pair. The scope of use of such products
Currently, coaxial single-core shielded cable finds its application in measuring and sound recording equipment, such as oscilloscopes and microphones. In the recent past, it was mainly used when laying local computer networks. But since when using a coaxial cable it turned out that poor noise immunity is associated with it, they began to look for other options for network connections.
Twisted-pair single-core cable is now used in orderly cabling computer systems. Its use lies in the direct contact of the equipment with the network. It is also used for laying in walls and boxes with subsequent connection to sockets, because the copper wire of the core of a single-core twisted pair cable has a large cross section and cracks when bent, and must be motionless. Stranded twisted-pair cable is strong in twisting and bending; it is used as a switching dynamic cable connecting network devices.
Thickness (section) of core and cable features
The cross section of a single-core cable or the thickness of the core depends on the strength of the current that flows through it, the voltage in the network and other factors. A cable is like a water hose, which, according to its inner diameter, can pass one or another amount of water. If the water pressure is increased, then the hose may explode, because such an amount of liquid will rush through it for which it was not designed. single corea shielded cable, like any other, of course, will not burst, like a hose, with an increase in current strength, but will burn out.
To facilitate the work of electricians, now, using formulas known from the school curriculum, tables have been calculated to determine the required cross-section of the cable core. It can be seen from them that with an increase in the values of voltage, power and current strength, the figures for the cross section of conductive wires increase. For example, a single-core rubber insulated copper cable with a continuous current rating of 40 A will have a cross section of 2.5 mm². If the wire is 50 A, then it will be 4 mm².
UTP cable. Key Features
In everyday life for information transmission, for communication lines and various low-current networks, a single-core UTP cable is the most popular product. The design of these types of cables is different. For networks of short length and with minor interference, products without protective shielding are used. In places where interference exists, cables that do not include a protective shield cannot be used.
Twisted-pair outer insulation, made of polyvinyl chloride, is colored differently. Functionality is determined by the color: gray is intended for indoor use, black indicates an additional layer that protects against external influences, orange color indicates that the shell is made of non-combustible plastic.
Marking, abbreviation
Cable marking tells about the characteristics of unshielded twisted pairs. The abbreviation UTP 5e stands for a 4-pair single-core UTP cable that provides good data and information transfer speed. Therefore, it is widely used for 1 Gb Ethernet. UTP 5 can be both single-core and stranded. But the UTP 3 cable is used in telephone networks. Because it is he who can only withstand low speed.
The main features of power cables. What are they and why are they used?
To transport energy by currents of industrial frequencies indoors and outdoors, single-core power cables are used. From switchboards operated by industrial or municipal enterprises, three-phase current is transmitted to consumers through such products by means of a stationary laying. In addition, multi-core power cables are used when connecting various mobile installations and equipment. All SCs differ in materials, sizes, designs, depending on the type and field of application. The basic structure of the cable includes a conductive rod, insulation and sheath. To isolate the power cable, paper impregnated with a special composition can be used. Usually mineral and synthetic oils and rosin are used. Some sections of cable trunks are treated with mixtures with the addition of synthetic ceresin.
Shells are formed from lead and aluminum. To improve the basic and protective performance, shielding, belt insulation, fillers, and armor are used. Core materials are usually copper or aluminum.
For example, for laying fixed connections in shields, use a single-core cable VVG 1 x 6 with one monolithic copper rod and a cross section of 6 mm². The service life of such a cable reaches 30 years. Cables are used strictly in those geographical areas for the climate of which they are designed. On the marking of the cable VVG 1 x 6 it is indicated: UHL1. These signs are deciphered as follows: it is possible to use in temperate and cold macroclimatic regions with operation in open areas with a likely strong wind.
Marking data of wires and cables are not only informational, but also a warning value: they help reduce injuries to workers associated with electricity.
Dignity of single-core
Finally, I would like to consider the advantages of single-core cables. One of their main advantages is the lower resistance of 1 km of wire. The second advantage is ease of installation. This feature applies, in particular, to contact connections. Another advantage is this low price.
Advantages of stranded
The main advantage of these cables is their flexibility. This is especially true for wires with a cross section of 10, 16 or more mm². Of course, such wires are practically not used in everyday life. But, in principle, they may be needed. Another advantage is that due to the availability of brass lugs on the market, cables can be easily mounted without any additional tools andfixtures. Stranded with screw terminals are used. Also, after special pressing, they can be used for WAGO terminals.
Small conclusion
Now you know what cables are, why they are used. We also considered the distinctive features of single-core and multi-core cables. In addition, we have described in detail where they are used. Therefore, when choosing between these two types, remember that each of them has its own scope. For example, if hidden wiring is mounted in the wall, then it will obviously be cheaper for you to stay on a single-core cable. When installing a temporary electrical installation, it will be much more practical to use a stranded product.
