Types of cables and wires, their purpose, characteristics and marking

The number of varieties of wires, electric cords and cables amounts to tens of thousands - only those produced in accordance with domestic GOSTs have registered more than 20,000. The good news is that it is not necessary to know “in person” all existing types of cables and wires and their purpose - it’s enough to understand the general principles of dividing them into types and be able to read the marking, which displays all the important characteristics.

Basic concepts

The characteristics of any cable or wire are determined by the properties of their conductive wires and the insulation surrounding them.

Lived in electrical wiring

Residential is a wire made of metal, capable of passing an electric current through itself. It has two most important characteristics - the number of wires of which it consists, and a cross section that determines the throughput.

According to the number of wires, the cores are divided into single-wire (monolithic) and multi-wire. This parameter determines the flexibility of the core - the more delays in it, the easier it bends. You should pay attention to this when choosing a wire or cable for certain purposes - if the wiring in the walls can be made with single-wire conductors, then to replace the power cord of the appliance, you need to take wires with multi-wire cores. There is no insulation between the individual wires of a multi-wire core - usually they simply twist together.

The cross-sectional area of ​​the conductors determines the total current power that can be passed through it. Since the cross section of the wire is the main parameter used in calculating the bandwidth of the wiring, manufacturers are required to indicate it on the insulation of the conductor. To avoid confusion, this is done at regular intervals - usually up to 1 meter, and if the wire is bare, the cross section is indicated on the package of the bay, but it is advisable to double-check it with a caliper or micrometer. You also need to be careful when buying inexpensive brands of wires - the GOST has certain tolerances for the thickness of the conductors and sometimes manufacturers actively use it. For example, there are wire brands with a tolerance of as much as 30% and if the accuracy of the equipment allows, then instead of 1 mm², you can get conductors with a cross section of 0.75-0.8 mm² and everything will be within the law.

There are also differences in the shape of the wires - they are mainly round, but in a number of varieties of wires and cables are made, for example, sector - single and multi-strand. This improves the overall layout of the cores and reduces the outer diameter of the entire product.

Electrical insulation

The main task of the insulating dielectric layer is to protect a person from contact with a live conductor. Also, the presence of insulation allows you to put several cores side by side, without fear of a short circuit between phase and zero (contact of the phase conductor with ground) or other phases.

For various purposes, certain dielectrics are used: ceramic or glass, and for flexible cables and wires, polymeric - polyvinyl chloride or celluloid. For household wiring, polymer insulation is most often used - its properties not only protect the cores from circuit, but also protect them from mechanical damage, high humidity and other external factors.

Armored wires and cables with multilayer insulation are also made, inside of which there is an additional braid or steel tape.They are used on unstable soils, when laying a line under roads and in similar conditions.

What are the differences between cable and wire

The same conductors of electricity can be called a cable, wire or cord. At the same time, in truth, both buyers and some sellers do not particularly bother with the correct wording.

Wire is the basis

By definition, a wire is one or more current-carrying conductors that connect two sections of an electrical circuit. The cores can be single and multi-wire, bare or insulated and differing in other characteristics. There is also a separate category of protected wires, which are easy to confuse with the cable, due to the presence of an external sheath - each core has its own insulation, and all together from the outside it is additionally closed with cambric made of polymers or similar materials.

Bare wires in domestic conditions are practically not used - they are often used to transfer electricity through overhead lines and in other places where a person does not get access without permission.

Insulated wires by themselves are poorly used in everyday life - they are more used inside various electrical equipment or in the electric network of an electric vehicle.

Cable - Prefabricated

The structure of the cable is similar to a sheathed wire - it is one or several current-carrying conductors, each of which is in its insulation, plus one more insulating and protective outer layer of polymers, plastic or rubber.

The main difference between the cable and the wire must be sought inside - if the last outer sheath is just a tube, then the space between the current-carrying conductors - threads, tapes or coated composition is additionally filled in the cable. This prevents the cores from sticking together, which can move slightly relative to each other when the cable is bent, which simplifies its installation and further maintenance.

In addition, armored cables stand out - they have several layers of external insulation, between which there is protection against mechanical damage in the form of a braid or interrupted metal bands.

Cord - Flexibility

The main use of electrical cords is to connect household appliances to the network. They must have increased flexibility and resistance to repeated bending, therefore, copper stranded cores with a total cross section of up to 4 mm² are used in the cords.

To avoid overspending of copper in the manufacture of devices, the cross section of the cords is selected depending on the power of the connected devices. For small electrical appliances, like an electric shaver, this will be 0.35 mm², 0.5 mm² is enough for TVs, and from 0.75 mm² for devices with an electric motor.

The cords do not have strict standards in length, but most often it is 1, 1.5, 2, 3.5, 4 and 6 meters. Often, electrical appliances are equipped with cords with non-separable (disposable) forks, and for some devices reinforcement is woven under the outer insulation to increase mechanical strength. If you have to change the electrical cord on a device with heating elements: an iron, a boiler, a kettle or an electric stove, it must be borne in mind that the insulation must be with increased heat resistance.

As a result, the main differences

An independent and separate unit is a wire - bare or insulated. Several insulated wires assembled in a bundle and twisted together are also a wire, but multi-core. If there is additional insulation on top of the stranded wire, then this is a protected wire. If there are additional elements between the veins of the sheathed wire: reinforcing threads, coating or part of the outer sheath is “recessed” between the wires, then this is already a cable. A flexible wire or cable made to connect to a network of electrical appliances is called a cord.

The difference of cables and wires depending on the core material

Conductors of wires and cables for specialized purposes can be made of various metals, but mainly aluminum and copper are used in electrical engineering.Each of them has its own specific properties, advantages and disadvantages that must be taken into account when selecting the core material for a specific purpose.

Aluminum conductors

The invention of a relatively inexpensive method for the extraction of aluminum made a revolution in the global development of electrification, because this metal is in fourth place in terms of electrical conductivity, passing only silver, copper and gold ahead. This made it possible to cheapen the production of wires and cables and make universal electrification a reality.

Such electrical wires and their types are distinguished by low cost, chemical resistance, high heat transfer and low weight - they determined the mass of electrification in industrial and domestic conditions for more than half a century.

In the light of the relatively recent dominance of aluminum in the wire market, it may seem strange to an uninitiated person to ban the provisions of the PUE on the use of this material in everyday life. More precisely, you can not use aluminum wires with a cross section of less than 16 mm², and this is the most common of them for installing home electrical wiring. To understand why there is a ban on the use of these wires, you can familiarize yourself with their advantages and disadvantages.

As a result, aluminum is a good choice if you need to save money here and now, but in the long run, its use will cost more - due to the relatively low service life and the need for regular maintenance. For this reason and additional safety reasons, it is strictly forbidden to use it for laying new power lines.

Copper conductors

Copper ranks second in electrical conductivity, only 5% behind silver in this indicator.

Compared to aluminum, copper has only 2 significant drawbacks, due to which it has been used much less frequently for a long time. Otherwise, copper wins in all respects.

As a result, although copper is a more expensive material, but in general its use is economically more profitable, since it is more durable, requires less installation effort and less attention during maintenance.

Cable and wire differences depending on insulation

In a cable or shielded wire, the insulation is divided into internal, covering each core separately and external (external). The first protects the cores from contact with each other and provides their protection from mechanical damage. The outer one holds all the cable components together and additionally protects the internal insulation from drying out, high humidity and other factors.

Insulation characteristics

When selecting insulation, its ability to withstand:

Voltage. In domestic conditions, this issue is not given special attention, since the vast majority of materials can withstand up to 660 or 1000 volts.

High temperature. When a current passes through a conductor, part of the energy is dissipated in the form of heat, which is dissipated from the insulation surface in the environment - air, if it is open wiring or goes into walls, if it is closed. At a certain moment, equilibrium sets in when the amount of heat released is compared with the heat given off. The temperature that is set at this moment should be in the range of the so-called working temperature, which the insulation of the wire must withstand for an unlimited time. For short-term overloads, there is also a temperature limit that the insulation must withstand for a certain time without consequences. The behavior of insulation during excessive heating is also indicated - burning, decay, emission of substances harmful to humans and others.

Low temperature. If the cable is to be used outdoors, then we must additionally look at the frost resistance indicator - at a certain subzero temperature, the insulation becomes brittle, which must be taken into account during installation and further operation.

UV Resistance. Part of the insulating materials, with other excellent characteristics, begins to deteriorate over time if it is exposed to sunlight. They become brittle and shrink - this must be taken into account if it is planned, for example, to post to the veranda or summer house.

Mechanical tensile strength. The bigger, the better, although, of course, taking a heavy-duty cable to repair the wire does not make sense to the bulb.

Insulation materials

A large number of insulating materials are used in electrical engineering - even just listing them all is quite difficult. But at the household level, it is enough to know those of them that are used most often - for internal wiring and bringing electricity to the house.

Additional elements of external insulation

Depending on the purpose of the cable, in addition to external insulation, the following elements are added:

Types of wires

The selection of the right wire largely depends on the power of electrical appliances that will be powered through it. Next, we examine the various types of wires that are most often used for domestic use.

Flat

1. PBPP (PUNP).

Flat sheathed wire with copper single-wire conductors, cross-section from 1.5 to 6 mm², located in one plane. The material of the external and internal insulation is PVC. It can be used at temperatures in the range of -15 / + 50, during installation it is allowed to bend around a circle with a radius of at least 10 diameters (since the wire is flat, the width is measured - the big side). Designed to transmit current up to 250 volts, frequency 50 hertz. It is used mainly for connecting lighting or outlets.

2. PBPG (PUGNP).

The letter "g" in the name indicates the hallmark of the wire - the flexibility that gives the use of multi-wire cores. It also reduces the bending radius during installation, which is 6 diameters. All other characteristics are the same as for a single-wire PBPP (PUNP).

3. APUNP.

The same PUNP wire, but with a single-wire aluminum core, cross-section from 2.5 to 6 mm². Other characteristics unchanged.

When purchasing PBPPP, PBPPPg and APUNP wires, it must be remembered that GOST determines the tolerance for them on the thickness of the core and insulation at 30%. This means that the cross-section of the wire marked 1.5 mm² in fact may well be ≈1 mm². In addition, the APUNP wire is prohibited for use by the provisions of the PUE and is made only because of the demand caused by the low price.

Although the insulation of such wires must withstand voltages up to 250 volts, but for the above reasons this is not always the case. Therefore, it is better to use them only for lighting, and for sockets to purchase NYM or VVG cables.

With jumpers

1.PPV.

The wire is easy to recognize thanks to the characteristic jumpers between the cores, which are made of the same material as their insulation - PVC. The number of conductors themselves is 2-3, they are single-wire, with a cross section of 0.75-6 mm². The wire can be used to transmit current with a voltage of 450 volts and a frequency of up to 400 hertz. The insulation does not burn, it is resistant to acids and alkalis - after installation, the wire can be used at temperatures of -50 / + 70 ° C and in conditions of 100% humidity (characteristic for 35 ° C). During installation, bending with a radius of 10 diameters is allowed.

2. APPV.

The same characteristics as those of PPV, but taking into account aluminum cores - the section starts from 2.5 mm². Purpose - installation of open wiring - lighting and power.

Single core

1. AR.

Separate single-core aluminum wire. The core with a cross section of 2.5-16 mm² is single-wire, and 25-95 mm² is multi-wire. Insulation material - PVC, resistant to chemically aggressive compounds, allows you to use the wire at a humidity of 100% (tests at 35 ° C), in the temperature regime of -50 / + 70 ° C. When installing, observe a bending radius of 10 diameters.There are no special restrictions for use.

2. PV1.

The same reclosure, only with a copper single-wire core, cross-section of 0.75-16 mm² and multi-wire 16-95 mm².

3. PV3.

The number in the name of the wire indicates the class of flexibility - here it is much higher, since it is multiwire for any core section. It is used for installation of lines where frequent transitions and bends are needed. The radius of the latter should not be less than 6 diameters.

The wires PV1, PV3 and AR are made with multi-color insulation, which increases the convenience of their use for mounting switchboards without the use of additional marking.

For the manufacture of electrical cords

1. PVA.

Copper stranded wire, with 2-5 stranded conductors with a cross section of 0.75-16 mm². The insulation of all cores of different colors, the shell is plain white. The purpose of the wire is a current transmission voltage of 380 volts with a frequency of 50 hertz. Due to its high flexibility, it is most often used for connecting electrical equipment - it is designed for a minimum of 3000 bends. For laying inside the walls is not recommended - in such conditions, after 4-5 years, the outer insulation will begin to break down. It can be used at temperatures of -25 / + 40 ° С, and in the modification of PVSU - from -40 to +40 ° С.

2. ShVVP.

Copper stranded wire, with 2-3 stranded conductors of increased flexibility with a cross section of 0.5-0.75 mm². It is used for the manufacture of power cords for fixtures or low-power electrical devices that require voltages of up to 380 volts and a frequency of 50 hertz. Not suitable for laying inside walls.

Types of cables

In addition to standard power cables designed to transmit electric current, there are a number of additional modifications that are used for other purposes or have separate functions.

Power cables

The main purpose of power cables is to lay internal or external electrical wiring for powering lighting devices and outlets. Most often, the following types of cables are purchased for this:

1. VVG.

One of the most popular and reliable power cables of domestic production. It is used to transmit electric current up to 1000 volts and a frequency of 50 hertz. Depending on the modification, single and multi-wire conductors with a cross section of 1.5-240 mm² are used. External and internal PVC insulation protects the cores from high humidity - up to 98% at a temperature of +40 ° С. Popular modifications of the VVG cable:

AVVG - the same VVG, but with aluminum single-wire conductors with a cross section of 2.5-50 mm².

VVGng - insulation does not support combustion.

VVGp - a flat cable in which conductive conductors are located in one plane.

VVGz - between the outer and inner insulation there is a filling in the form of rubber chips or additional PVC threads.

All varieties of insulation have good mechanical and chemical resistance, bending radius of 10 diagonals.

2. NYM

By construction, it is an analogue of VVG cable, but made not according to Russian guests, but European standards developed by German engineers. With equal physical characteristics, the NYM cable is considered more reliable, since the materials that are used in its manufacture are better and the tolerances are tighter. A distinctive feature of the cable is the layer between the inner and outer insulation of coated rubber

According to its characteristics and purpose, NYM is a household cable for mounting sockets or lighting - it consists of 2-5 conductive multi-wire copper conductors and is designed for a voltage of 660 Volts. The insulation quality allows the cable to be operated at temperatures of -40 / + 70 ° C, and the bending radius during installation is only 4 diameters.

NYM cable is used for laying external and internal wiring. There are only two limitations - to prevent exposure to direct sunlight and not to lay the cable directly in freshly poured concrete - in such cases, corrugated pipes or cable channels should be used.

Depending on the number of cores, their insulation is painted in the following colors: black, blue, yellow-green, brown and another black with an additional mark.

3. KG - flexible cable.

1-6 stranded copper cores are designed for AC voltage up to 660 Volts and a frequency of up to 400 Hertz. The material of internal and external insulation is rubber, which gives the cable increased flexibility and makes it possible to operate at temperatures of -60 / + 50 ° С.

It is mainly used for connecting powerful electrical equipment to the network - welding machines, heating devices, generators, etc. If necessary, you can use it for installation of power wiring, but it is quite expensive - if possible, it is easier to choose NYM or VVG.

4. VBBShv.

Copper cable with single or multi-wire conductors with a cross-section of 1.52-240 mm², in an amount of 1-5 pieces. External and internal insulation are made of PVC - all the voids between the cores are filled with the same material. Under the outer shell, armor is made of two metal bands that are wound with an overlap. The insulation can withstand voltages up to 1000 Volts and can be operated at temperatures of -50 / + 50 and humidity up to 98% (at +35 ° C).

The following modifications are common:

• AVBBSHv - with aluminum conductors.
• VBBSHvng - insulation is off.
• VBBSHvng-LS - insulation during smoldering almost does not emit smoke and caustic gas.

During installation, the bending radius must be maintained from 10 diameters.

5. Glowing cables.

When such a cable is connected to the network, its insulation surface starts to glow.

This effect is caused in two ways:

LEDs. External insulation is made in two layers, one standard, and the second transparent. Between them, at a distance of 2 cm, LEDs are arranged sequentially to each other. This design is very convenient in terms of searching for a breakage of a current-carrying core - in this place the LEDs will stop glowing. Such cables are made by Duralight - most often they are used to power stage equipment, but there is a line of luminous computer cables.

Luminescent coating. When connected to the network, it emits a uniform glow throughout the area, which resembles neon tubes. The advantages of this solution are its relatively low cost and the absence of restrictions on cable length.

Information Cables

The very first of them were used to connect telephones and television antennas, but with the development of computer technology, new types of cables for transmitting information appeared.

1. RG-6, RG-59, RG-58, PK75.

Such cables are better known to lay people as “antennas”, which consist of a single or multi-wire copper core with a cross section of the order of 1 mm², thick internal insulation made of dense or foamed polyethylene, a shielding braid and an outer insulating layer - cambric.

Without going into technical details, it is enough to know that such a cable structure is ideal for transmitting low-current high-frequency signals. When purchasing such a cable, a specialist will be interested in such characteristics of the transmitted current as frequency, resistance, type of shielding, signal attenuation time, etc.

2. Computer twisted pair.

If a special fiber optic cable is used over long distances, the so-called twisted pair cable is used to connect computers to local networks. Most often, these are 4 or 8 wires interconnected in pairs - this design improves the reception and transmission of the signal.

Since twisted pair wires are usually thin and can easily be damaged, next to them is a tensile thread that can be easily torn and cut from the inside with an external protective insulation.

There are several varieties of such cables that differ from each other by the presence or absence of additional shielding to stabilize the signal passing through the veins:

• UTP - with ordinary external protective PVC insulation.
• FTP - a foil screen is wound under the outer insulation.
• STP - the screen is made in the form of a braid made of copper wire. In addition to general shielding, each twisted pair is protected separately.
• S / FTP - foil screen under general isolation and on each twisted pair.

By the number of twisted pairs, the cables are divided into categories CAT1, CAT2 and CAT5e - the last of them is 4 pairs of wires, which allows you to transfer data at speeds up to 1 Gb / s.

3. Telephone cables and wires.

Low-current cables - are mainly divided into lines used for laying between telephone substations and for installing individual branches in a house or apartment.

TPPep. Multi-core cable - depending on the version, it is designed to connect up to 400 subscribers (2 wires for each). The cores are used single-wire, with a cross section of 0.4-0.5 mm², insulation - polyethylene. In addition to modifications in the number of wires, there are armored cables suitable for laying in the ground without additional structures.

TRV (noodles). 2 or 4 single-wire copper conductors with a section of 0.4-0.5 mm², enclosed in a PVC sheath with a divided base. The insulation withstands operation at temperatures of -10 / + 40 ° С and relative humidity not higher than 80% (at +30 ° С).

TRP. The same expansion valve, but with polyethylene insulation, which makes the wire suitable for outdoor use.

SHTLP. Flat sheathed wire of increased flexibility with two or four stranded conductors with a cross section of 0.08-0.12 mm². PVC inner insulation, polyethylene outer layer.

PRPPM. Flat protected two-wire wire with single-wire conductors with a cross section of 0.9 or 1.2 mm² and a divided base. Depending on the modification, the inner insulation is made of PVC, and the outer one is made of polyethylene or double PVC. The wire is suitable for operation at temperatures of -60 / + 60 - it is used for laying an external line on the walls of buildings or on air supports.

Specialized Cables

Designed for use in non-standard conditions - with temperature, humidity, pressure, etc., differing from standard ones.

1. PNSV.

The heating wire, designed not to transmit, but to consume electricity. The vein with a section of 1.2, 1.4, 2, 3 mm ² is made of steel and covered with a defense or galvanized steel. Insulation made of heat-resistant PVC or polyethylene, which retain their properties in the temperature range -50 / + 80 ° С. The wire is designed to connect to the line 220-380 Volt 50 Hertz and is most often used for the manufacture of underfloor heating.

2. Runway.

Cable with a copper multi-wire core of 1.2-25 mm² in double insulation made of polyethylene or PVC. Designed to operate at voltages up to 660 volts and a current frequency of 50 hertz. Insulation withstands sudden changes in pressure and allows cable operation at temperatures of -40 / + 80 ° С. A popular area of ​​application is the feeding of pump motors lowered into artesian wells.

3. RKGM.

Power copper single-core heat-resistant installation wire. A multi-wire flexible conductor with a cross-section of 0.75-120 mm² is designed for voltages up to 600 Volts at a frequency of up to 400 Hz. Silicone rubber insulation with an outer shell of fiberglass, plus impregnation with heat-resistant varnishes or enamels - retains its properties in the temperature range -60 / + 180 ° C. These types of wires are used for operation at many times elevated temperatures - wiring in furnaces, baths, connecting heating devices, etc.

Cable Product Labeling

The alphanumeric designations that make up the name of the cable displays all the most important information about its characteristics: what the core and insulation are made of, the purpose and design differences, the number and cross-section of the wires, additional features. Some letters may be absent, thereby designating some general parameter.

Letter 1. It can only be “A” - denotes an aluminum core. If the marking begins with any other letter, then the first is missing and the cable is copper.

Letter 2. Shows what the cable is for:

• M - mounting
• MG - flexible mounting
• P (U) or W - installation
• K - control

The absence of the second letter indicates that this is a power cable.

Letter 3. Material and type of internal insulation. The most common notation:

• P - polyethylene
• B or BP - polyvinyl chloride
• P - rubber
• N or HP - non-combustible rubber
• C - fiberglass
• K - capron
• D - double winding
• Ш - polyamide silk
• E - shielded

Letter 4. Design features:

• G - flexible
• K - armored, braided with round wire
• B - armored tapes
• Oh - braided
• T - laid in pipes

Add. Letters - lowercase cyrillic or latin capital letters indicate the features of the cable subspecies:

• h - filled
• ng - non-combustible
• HF - when smoke emits little smoke
• LS - when burning emit little gas

Digit 1. Number of cores.

Number 2. Cross section lived.

Number 3. Rated voltage for which the wire is designed.

These are far from all possible designations - only those that are used in widespread cables and wires for domestic use. If necessary, the decryption can be looked at the tag or ask the seller.

Example of decoding of marking: AVVGng 3x2.5

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