Appointment of electrical cables. Types of wires and cables for laying home electrical wiring

In each of these categories, there are many types of cable and wire products identified by special markings. Structurally, cables and wires differ in the overall parameters of the conductive cores and the material from which they are made, the type of sheath and external protective cover, the design of the armor (if provided) and other criteria that determine the scope of products and their operating conditions.

The types of electrical cable and the decoding of their brands are individual for each individual category of products.

Power cables

This type of cable products is used to solve the problems of transporting electricity over short and long distances. The most important physical parameters of power cables are voltage and current load (permissible value of the transmitted current).

Here are some brands of power cables and their areas of application:

Signal cables and wires

This category of electrical cables and wires includes cable and wire products intended for building fire and/or security alarm systems. Their main task is to transmit electrical signals from analog and digital sensors for smoke, motion, temperature, etc.

Cables are also used to supply power to light and sound signaling devices, movement direction indicators (for quick evacuation of people during a fire), automatic fire extinguishing devices and other devices. An important difference lies in their increased resistance to high temperatures, which, in particular, is one of the main requirements in the design of fire safety systems.

Common types of electrical cables and their marking: KPSVVng (A), KSVEVng (A), etc.

Alarm and interlock cables

This type of cable is used to control electrical mechanisms located in the open air. Most often used for laying along urban and federal railway routes to adjust the operation of arrows, signaling devices, traffic lights. They are also used, for example, to control barriers in car parks.

The Cable.RF ® company is one of the leaders in the sale of cable products and has warehouses located in almost all regions of the Russian Federation. After consulting with the company's specialists, you can purchase the brand you need at competitive prices.

Large apartment repairs necessarily include the replacement of electrical wiring. There are two main reasons for this action.

The first is the age of this very wiring. As a rule, overhaul or any major repairs are carried out in 15-20 years after the delivery of the apartment. During this time, even a properly made home electrical network ages and wears out. So, it potentially becomes a source of danger for the inhabitants of housing.

The second reason is the redevelopment and extensive renovation of individual premises with the addition of new electrical appliances. Inserts and other connections of new wiring with the old one are highly undesirable. Due to a mismatch in the characteristics of the cable or the materials in it.

So, the question - whether to change the wiring, is considered resolved, it remains to deal with its practical implementation. And you need to start with the choice of cable.

Cable for electrical wiring in the apartment - 300 brands and 5000 varieties

Which side to start from? A person who is far from electrical installation will grab his head. And there is something to grab. Because there are not just a lot of cables and wires, they literally cannot be counted, like Donov Pedro in Brazil. Even professional electricians sometimes "drown" and get confused in the abundance of manufacturers and products.

The choice of wire for electrical wiring in an apartment is not only a matter of the cost of repairs. Much more important is the point that the wiring should ensure the “delivery” of electricity to any corner of the apartment and be safe, that is, not “bite” with current. And also be fire resistant and reliable.

Attention! The key to reliable electrical wiring is finding the right electrician. A specially trained master should deal with electricians and choose a cable for wiring in an apartment! Who has a permit for electrical work and practical experience.

We will briefly talk about cables and wires, their cross-section, marking, materials and types. We will explain what is suitable for home wiring and what cannot be used. So that you are aware of what your electrician is doing and why.

Characteristics of wires and cables to pay attention to when choosing

We will immediately stipulate that we are talking about a household power cable or wire with a voltage of 220/380 V for transmitting electric current in a home network. We do not consider all other types like heating, television, computer and others now.

The general list of characteristics looks like this:

• core material;
• design;
• section;
• thickness of core insulation;
• shell thickness;
• marking;
• lived coloring;
• package;
• certificate;
• product condition.

1. Material and design

According to the composition of the vein, cable products are divided into copper and aluminum. Copper products are more reliable, resistance is lower, current indicators are higher, heating is less when compared with aluminum of equal cross section. In addition, copper oxidizes less, is more ductile, which means that the cable lasts longer without loss of properties and characteristics.

Attention! It is forbidden to do wiring in an apartment with an aluminum cable in accordance with the requirements of the PUE (rules for electrical installations).

By design single-core (single-wire) and multi-core (multi-wire) cables and wires are produced. Single-core varieties are more rigid and inflexible, especially with a large conductor cross section.

Answering the question “which wire to use for wiring under plaster”, we can say that theoretically a single-core single-wire copper cable is also suitable. Plaster will create additional protection for such a conductor. But in fact, no one is laying a home electrical network with a single-wire wire.

Stranded single-core cable is softer and more ductile. It tolerates kinks and turns well and is suitable for both open wiring and hidden under plaster. It is the three-core single-wire that is now used for laying in apartments.

Attention! Do not confuse cables where each strand consists of a single conductor with wires where the strand is made of several conductors. Multi-wire cable products are prohibited for fixed laying in an apartment due to a high fire hazard. More about them in the block"what wires can not be used for electrical wiring in the apartment"

2. Cable cross section for wiring in the apartment

It is measured in "squares", that is, square millimeters and shows the throughput. For a copper cable, one “square” passes 8-10 Amperes of current, for an aluminum cable only 5 A. For safe operation, the conductor should be selected with a margin of bandwidth, which ensures that the wire is heated within the permissible value, or, more simply, so that the load does not “float” insulation. In addition, with hidden wiring, it must be borne in mind that it is less cooled, which means that the section margin should compensate for this.

Attention! Do not confuse the cross section of the cable with its diameter, these are two big differences! The diameter can be measured with a ruler, or better with a caliper. And then substitute it into the formula and calculate the cross-sectional area.

Also remember that the choice of cable for wiring in the apartment always comes with rounding up. If the calculation results in 2.3 "squares", a cable of two and a half is selected, and not two "squares".

Ideally, the cross section should match the marking on the cable tag, but in fact it often differs downwards. Small discrepancies are acceptable because the cable is certified by resistance, not core cross-section. If the differences are significant, it is a marriage. An experienced electrician will see it visually, and you can measure the diameter of the core and calculate the cross section for interest or help a friend who decides to buy a cable for residential wiring on his own.

Some electricians advise taking a cable with a rating higher than the calculated one. For example, 4 "squares", instead of 2.5, to cover the "lack" of the section, if any. But, then you will have to calculate the protection of the wiring accordingly and install the correct machines and RCDs.

Advice! We recommend for electrical wiring in the apartment the cross section of copper wires from 1.5 to 2.5 square meters. mm. Let two and a half "squares" into sockets and one and a half - for lighting.

3. Thickness of core insulation

Each core in a multi-core or single-core cable is insulated with conventional or low-flammability PVC compound, polymers and cross-linked polyethylene are also used. The thickness of the insulation is regulated by GOSTs and it should be sufficient. For household cables (rated voltage up to 660V) with a cross section of 1.5 and 2.5 mm 2, the thickness of the insulating layer according to the standard is 0.6 mm. Deviation is allowed, but the insulation should not be thinner than 0.44 mm.

Simply put, there is a gap in thickness where the insulation must “fit in” so that the wiring serves reliably and there are no problems during installation. Whether the manufacturer violated the technology - you can’t determine without a micrometer if you don’t fiddle with cables every day. Therefore, if there is no experienced electrician nearby, you need to buy only in trusted stores and cables of famous brands.

4. Shell thickness

The sheath covers the cable over the insulated cores, fixes them and protects them. It is made, like the core insulation, of PVC compound or polymer, but has a greater thickness. For multi-core cables, the thickness is 1.8 mm, for single-core cables - 1.4 mm. Smaller deviations are also possible, but insignificant.

The insulating shell is a mandatory element. For any residential wiring cable, even with a minimum power, double insulation is “registered”. That is, first on the core, and then on top of it. This ensures the safety of people and protects the conductor itself from damage.

5. Marking

This is an inscription on the cable sheath for wiring in an apartment. It contains all the information you need to make a selection. The inscription is printed or squeezed out during the manufacture of cable products. It should be clear, contrasting, well readable.

The labeling states:

• The brand of the product (cable or wire), in which the main properties and characteristics are encrypted.
• Manufacturer's name.
• Year of issue.
• The number of lived
• Section.
• Voltage rating.

The inscription is applied along the entire length of the conductor at small intervals.

On the price tag and in the catalogs of online stores, they usually do not indicate the year of issue and the manufacturer and write the marking in the form VVGng(ozh)-0.66 kV 3x1.5 or VVG, VVGng cable 3x1.5.

Deciphered as a three-core copper cable with a core cross section of 1.5 "square" (3x1.5), single-wire core (OJ). Insulation and sheath made of PVC compound (VV), flexible cable (G), non-combustible (ng). Rated voltage 660 volts.

Remember! The letter designation of the cable brand begins with the material of the core, for aluminum the letter A is always put, for copper — the letter is not indicated, therefore all cables of the VVG brands of all modifications have a copper conductor.

6. Coloring of cores

You need to know about the coloring that it is either solid color, or a strip is applied on the sheath along the entire cable with a width of about a millimeter. This is the standard. Everything else, in the form of smudges, spots, stripes across - from the evil one. And he says that incomprehensible people made the cable in some basement.

According to the colors of the veins, there is a table that any experienced electrician knows. It is written there what shade the main conductors are indicated - phase, zero, grounding. This was done for ease of installation, in order to see where which conductor to connect. Phase and working conductors may differ in color, but the “earth” is always “painted” in yellow-green color.

7. Packing

Standard for all types is a bay or a drum. Coils go for sale in stores, they are wound on drums for wholesalers, builders and other large buyers. In any case, a label with a description is attached to the cable.

The content of the tag repeats the information of the inscription on the shell with some additions. It states:

• manufacturer's name or trade mark
• brand (designation) of products
• GOST or TU
• Release date
• number of segments with their length
• drum number
• conductor weight
• mark of conformity
• OTC mark.

If you came to buy a cable for wiring in an apartment with a whole bay of 100 m, you will receive a tag along with it. But if a piece is cut off for you, then the label will not be given away, you can just look at it.

8. Certificate

It is necessary to confirm that the cable is of high quality. Typically, products have 2 documents - a certificate of conformity, which is responsible for the suitability of the cable as an electrical installation material, and a fire safety certificate. You can ask the seller to review them. Documents must be filled out indicating GOSTs for the cable and have a valid deadline, for example, until the end of the current year. As a rule, the documentation indicates TU (technical specifications) according to GOST and for cable products this is tantamount to compliance with GOST.

9. Condition

This is the appearance of the power wire. Pay attention to how the cable looks, because behind the bruises, strong kinks, and compression, there is an internal defect. The veins can be broken and even closed to each other. It is clear that it is impossible to lay such material, therefore, do not be too lazy to inspect the cable in the store, even before paying for an independent purchase.

What cable is needed for wiring in the apartment

We have already said that the wiring in the apartment "requires" 2 cable sections.

For sockets, you need to take a cross section of 2.5 mm 2, because the included load can reach 3-4 kilowatts. A cable of two and a half "squares" is just designed for a maximum power of up to 5.9 kilowatts and a current of up to 27 amperes. This does not mean that you need to "load" the cable line to the limit. The choice always comes with a margin of the planned load by a third. Moreover, the cable lying under the plaster cools less and this is also taken into account when selecting.

For the lighting circuit, a cross section of 1.5 mm 2 is used. The load here is much less, but even if you decide to arrange illumination in the apartment, the current and power reserve will be more than enough.

Important information! Since modern electrical safety rules require grounding household electrical appliances and installing special sockets, a three-core cable is used for installation. In which, there is a working phase conductor, zero working and protective zero.

Which cable does the online store recommend for hidden wiring in a house or apartment

Recall that the marking contains the main characteristics of cable products. The letter designations indicate the materials of the cores, insulation, sheaths and flexibility, the digital designations indicate the number of conductive cores and their cross section.

VVG cable

The most common domestic cable for electrical installation in an apartment. It has single-core copper conductors, insulation and sheath made of PVC compound, it is used in rooms with normal and high humidity. Designed for voltage up to 660 volts. Refers to flexible unarmoured power wires. It can include from 1 to 5 cores, with a cross section from one and a half to 240 "squares". The shape of the conductor is round, flat or triangular.

VVG cables are available in several modifications:

• VVG - the main type with vinyl insulation and sheath;
• VVGng - non-combustible power wire, self-extinguishing core insulation, that is, combustion does not spread;
• VVGng-LS - also has self-extinguishing non-combustible core insulation (ng) and a sheath with low smoke emission;
• VVGng FR-LS - in addition to incombustibility and low smoke, this type of cable received additional fire protection from mica tape.

All brands with the prefix ng can be mounted in bundles, that is, lay several cable lines in one corrugation, pipe or pit.

Conventional VVG is cheaper, but not suitable for bundled gaskets and the jacket is less fire resistant and fuming. And the VVGng FR-LS brand is professional and is used in conditions of increased fire hazard at enterprises and is much more expensive.

NYM cable

European standard copper cable developed in Germany. It is produced at Russian factories and complies with EU and GOST standards. It is similar in design to the VVGng cable, rated voltage is 660 V. A single-wire stranded NYM cable with a cross section of 1.5-10 mm2 and a multi-wire cable with a cross section of 16 mm2 or more are produced. Number of cores 1-5, PVC insulation and sheath, incombustibility is ensured by a rubber filler between the core insulation and the cable sheath.

Note! In stores you can find cheap cables marked NUM. This "typo" says that you have a copy with reduced performance. By buying it, you risk getting low-quality products. We advise you to refrain from dubious savings on security.

VVGng and NYM cables have similar characteristics and advantages of use:

• Quality performance. Cores, insulation, sheath comply with GOST and this makes the cable reliable.
• Convenient installation and easy cutting. The round cable is easy to install due to the absence of twists, it is easier to seal it during input.
• High fire resistance and safety. Compliance with standards ensures safe operation of the cable under load, and special insulation allows it to be laid in bundles, without the risk of ignition from mutual heating.
• Self-extinguishing and low smoke. The sheath material is self-extinguishing and slows down combustion. It also provides low smoke without dangerous halogens. If the protection works with a delay, then the damage from fire will be minimal.
• Large selection of options in stamps at a price for any budget.

Which wire is not suitable for wiring in an apartment

And one more important point. We understand that for most people "wire" and "cable" are synonymous. In fact, these are different types of cable products. The main difference is that the cable always has a very strong two-layer insulation, with the first layer over the conductive cores and the second one covering the entire bundle. Even if there is only one core in the cable, the insulation is always double. Wire is a weaker construction with light insulation.

Note! Making wiring in an apartment with a wire, even stranded or stranded, is a very bad idea.

The main trouble with wires is their poor resistance to prolonged heating under constant load and high flammability. Therefore, they do not meet the requirements of the PUE for wiring in residential premises.

PVC wire

This is a connecting copper wire with vinyl insulation and sheath. Used to connect household electrical appliances to the home network, for the manufacture of extension cords. The number of conductors is 2-6, the core structure is multi-wire, the cross section is 0.75-10 mm2. Designed for a voltage rating of 380 V.

Attention! No need to take the PVA wire for wiring on the advice of friends or from savings.

• Firstly, PVS have a multi-wire core design. And this means that all the ends for the connection must be tinned and must be soldered. This takes a lot of time and requires high quality core processing and a lot of experience from an electrician.
• Secondly, the multi-wire core construction is a factor of increased fire hazard. Such a wire heats up more, which means that the insulation wears out faster, which is dangerous and can result in a short circuit.
• Thirdly, the PVA wire cannot be laid in a bundle, like a cable. Only with the distance between the threads. That is, ditch the walls for each line separately.

So, the savings are very doubtful and symbolic. The low price of the wire will be "eaten" by the high cost of installation. And the quality of the wiring leaves much to be desired.

Wire SHVVP and PVVP

Mounting cords or cables with single and stranded copper conductors. Used to connect electrical equipment and household appliances. They have a short service life, the stranded type requires processing of the ends and soldering during installation. They are not suitable for fixed wiring due to the lack of non-combustible insulation and poor performance.

Wire PUNP

Attention! PUNP has been banned for wiring since 2007 due to its unreliability.

Although there are "craftsmen" among both customers and unfortunate electricians who use it. Motivating this by the fact that "it is he who stands in all the old apartments."

But the "citizens" forget that since the days of the USSR, the equipment of home electrical equipment has changed a lot and its power has increased. Therefore, PUNP was banned - it is low-power, with poor insulation and does not hold modern loads.

The online store site offers only high-quality cable for electrical wiring in an apartment or house. A complete list of brands and types in the section:

Come and choose your cable!

Also, ask any questions. Funny and naive in the first place! They are the most correct! Because it's better to make electricians laugh than firefighters, agree?

We always answer questions and talk about all the intricacies of installation. We quickly select a complete set for the device of apartment wiring from cable to sockets and switches. We take into account your wishes and budget.

Call, ask! Phones

During the development of local networks, quite a lot of types of cables have appeared, and all of them are the result of increasingly complex requirements of standards. Some of them have already become a thing of the past, and some are just beginning to be used, and thanks to them, it became possible to implement the high data transfer rate that we need so much.
In today's article, I will talk about main types of cables And connectors, which have become widespread in the construction of wired local networks.

Coaxial cable

Coaxial cable- one of the first conductors used to create networks. A coaxial cable consists of a central conductor enclosed in thick insulation, a copper or aluminum braid and an outer insulating sheath: To work with coaxial cable, several different types of connectors:

Installed at the ends of the cable and is used to connect to the T-connector and barrel connector. . It is a kind of tee that is used to connect a computer to the main line. Its design contains three connectors at once, one of which is connected to the connector on the network card, and the other two are used to connect the two ends of the trunk. . With it, you can connect the broken ends of the trunk or sharpen part of the cable to increase the radius of the network and connect additional computers and other network devices. . It is a kind of stub that blocks the further propagation of the signal. Without it, the functioning of a network based on coaxial cable is impossible. In total, two terminators are required, one of which must be grounded.

Coaxial cable is quite susceptible to electromagnetic interference. Its use in local computer networks has long been abandoned.
Coaxial cable has become mainly used to transmit a signal from satellite dishes and other antennas. The coaxial cable received a second life as a backbone conductor of high-speed networks, in which the transmission of digital and analog signals is combined, for example, cable television networks.

twisted pair

twisted pair is currently the most common cable for building local networks. The cable consists of pairs of twisted copper insulated conductors. A typical cable carries 8 conductors (4 pairs), although 4 conductors (2 pairs) are also available. The colors of the internal insulation of the conductors are strictly standard. The distance between devices connected by twisted pair should not exceed 100 meters.

Depending on the presence of protection - electrically grounded copper braid or aluminum foil around twisted pairs, there are types of twisted pair:

Unshielded twisted pair (UTP, unprotected twisted pair). Apart from the conductors with their own plastic protection, no additional braids or ground wires are used: Foiled twisted pair (F/UTP, foil twisted pair). All pairs of conductors of this cable have a common foil shield: shielded twisted pair (STP, protected twisted pair). In this type of cable, each pair has its own shielding braid, and there is also a mesh screen common to all: Screened Foiled twisted pair (S/FTP, foil shielded twisted pair). Each pair of this cable is wrapped in its own foil sheath and all pairs are encased in a copper shield: Screened Foiled Unshielded twisted pair, unprotected shielded twisted pair). Features a double shield of copper braid and foil braid:

There are several categories of twisted pair cables, which are marked from CAT1 before CAT7. The higher the category, the better the cable and the better performance it has. In local computer networks of the Ethernet standard, twisted pair cable of the fifth category (CAT5) with a frequency band of 100 MHz is used. When laying new networks, it is desirable to use an improved cable CAT5e with a bandwidth of 125 MHz, which better transmits high frequency signals.

To work with a twisted pair cable, an 8P8C (8 Position 8 Contact) type connector is used, called RJ-45:

Fiber optic cable

Fiber optic cable- the most modern data transmission medium. It contains several flexible glass light guides protected by heavy duty plastic insulation. The transmission speed of fiber optics is extremely high, and the cable is completely immune to interference. The distance between systems connected by optical fiber can be up to 100 kilometers.

There are two main types of fiber optic cable - single mode And multimode . The main differences between these types are associated with different modes of passage of light rays in the cable. For crimping a fiber optic cable, a variety of connectors and connectors of different designs and reliability are used, among which the most popular are SC, ST, FC, LC, MU, F-3000, E-2000, FJ, etc.:
The use of optical fiber in local area networks is limited by two factors. Although the optical cable itself is relatively inexpensive, the prices for adapters and other equipment for fiber optic networks are quite high. Installation and repair of fiber optic networks requires high qualifications, and expensive equipment is needed to terminate the cable. Therefore, fiber optic cable is mainly used to connect segments of large networks, high-speed Internet access (for providers and large companies) and data transmission over long distances.

Electrical wires must carry out the transfer of electrical energy from the source to the consumer. These products must perform their tasks for a long time, be reliable, and prevent malfunctions. These products include cables and wires. They are used in almost every industry and human life. Electrical wires are necessary for the formation of a closed circuit of electric current, preventing its loss in this circuit. People who do not understand electrical engineering, do not distinguish between different types of electrical wires, attribute all types to one category.

But this is absolutely not true. Power wires are used in various working conditions, on different highways, they have many differences in application, their structure is arranged differently, and they have design features. Lines of electrical networks can consist of both overhead wires and underground cables.

Branching of the cable on the overhead line is carried out for special purposes required by local conditions.

Electric wires

The wire has the simplest design, which can be divided into two parts:

1. The core is made of metal, designed to conduct electric current.
2. An insulating layer that protects the core from contact with foreign conductors, in order to avoid unauthorized leakage of current.

Air around the metal core instead of a sheath of dielectric materials can also act as insulation. In this case, the wire is made bare, and the places where the wire is attached along its path on the supporting structures (pillars) are made in the form of insulators (glass, ceramic).

The conductors that conduct electric current are made of copper alloys and copper, as well as aluminum. The most innovative material of the current-carrying core is currently composite aluminum copper. It is designed to make better use of the properties of copper and aluminum.

To perform special tasks, conductors made of steel alloys, as well as nichrome and silver, are used. In some cases, gold is used in the veins for special equipment.

Features of the structure of the conductive core

The vein can be in the form:

• Solid wire (single core), having a certain length.
• Twisted from the thinnest wires (multicore) acting in parallel.

Wires with one wire are much easier to make. They have a rigid shape, are used to supply electric current when rigidly attached to supports, have low resistance when transmitting low-frequency currents, direct current.

The cores, consisting of many wires, have a very flexible shape, conduct high-frequency current well.

Types of wires

Often a wire is a product in which one core is made of wire. But electrical wires may have multiple strands, twisted or twinned, with three or more strands.

Electrical cable

The cable has a more complex design, it is designed for reliable operation under the aggressive action of negative environmental factors.

The number of conductors conducting current is selected according to the operating conditions. They are isolated from each other.

The cable may have auxiliary elements:

• Protective braid made of steel, wire armor or plastic.
• Filler.
• Core.
• outdoor screen.

Each element performs its purpose functions for certain conditions.

Electricians should know the main groups, which include cables and electrical wires:

• Power, operating in installations for any voltage.
• Control, transmit data parameters of different systems.
• Controls are used to give signals and commands automatically or manually.
• Communications, for the exchange of signals at different frequencies.

A separate group includes cables for special purposes:

• Emitting, used to supply high frequency radio signals.
• Heaters convert electricity into heat.

Conductors

Cable cores are made according to the same rules as wire cores, from various materials, with one conductor, or multi-wire, protected by a layer of insulation. According to the flexibility of the structure, the cables are divided into 7 groups. Group No. 1 includes cables that are difficult to bend, have a monocore. The most flexible group is #7. Cables of this group are the most expensive.

Before installation, electrical wires with multi-wire flexible conductors are equipped with special lugs in the form of tubes (terminators). In the case of a solid wire, tubes are not installed, since this makes no sense.

Shell

It performs the function of protecting the core and isolating it from environmental damage, creates tightness from moisture and other factors, contains several layers of shielding and reinforcing elements.

The shell may consist of:

• Plastic.
• Fabrics.
• Metal.
• Reinforced rubber.

Plastic-based materials are used for:

• Insulation of cores and wires with increased dielectric characteristics.
• The formation of a hose with high tightness, which protects against damage and short circuits, with a structure of elements placed in it.

Cable paper impregnated with a special composition is used in high voltage cables up to 35 kilovolts. Cross-linked polyethylene is used to form the insulating properties of a cable operating in electrical devices up to 500 kilovolts with increased reliability and a long service life.

For high voltage circuits up to 500 kilovolts, cables filled with oil were previously produced. They consisted of shielded wires installed inside a sealed cavity filled with oil. After cross-linked polyethylene began to be used, the design of oil cables became irrelevant.

Security conditions

Cable products are subjected to a special assessment, which includes:

• Behavior of the cable when shorting in the channel.
• Can the cable withstand long overloads.
• Behavior of the cable in open fire, the possibility of spreading fire in case of fire.
• The presence of toxic substances during combustion.

The occurrence of short circuits

During the closure of the cores, a high temperature is formed, which is transmitted to other cables located nearby, heats them up, and can provoke combustion. As a result of this, gases are formed that create an increased pressure, and the tightness of the cable channel is violated. Further, air enriched with oxygen enters the channel, a fire develops.

Long overloads

A large electric current heats the metal conductors and the dielectric layer of insulation together with the sheath. Chemical reactions begin, destroying the insulating layer, gases are formed that mix with air, a fire flame is formed.

fire spread

Sheath made of plastic and some grades of polyethylene may cause fire. This allows a fire to start. The greatest danger arises when the cables are arranged vertically.

According to the spread of burning, electrical wires are divided into:

• Usual.
• Non-flammable in single laying: horizontally and vertically.
• Flame retardant, made of several gaskets: horizontally and vertically.
• Fire resistant.

Release of harmful substances

A record of the cable's response to an external fire is kept. Insulation can release harmful substances simply when heated, without burning. These cables should not be used in public places.

Cable Requirements

To increase reliability and safe operation, cables are evaluated by:

• Fire resistance.
• resistance to heat insulation.
• end cutting method.
• Protect from moisture.

Electrical cord

Cord construction is a product that is intermediate between a cable and an insulated wire. The cord is made using a special technology for flexibility and long-lasting performance.

The cord is used to create a connection between the mains supply and a mobile electrical device. Household appliances equipped with cords include: kettles, irons, lamps, etc.

Marking

To distinguish electrical wires are marked under the following circumstances:

• At the factory during manufacture.
• When installing.

The label includes:

• Insulation color code.
• Shell inscriptions.
• Labels and tags.

Marking allows you to:

• Find out the purpose and design of the cable.
• Make a property analysis.
• Make an appraisal.

Marking during operation adds information to the available information and is produced by inscriptions and tags, which indicate the schemes and ways of laying the cable, lived between the elements. Marking can be supplemented with electronic markers. This makes it possible to identify a cable in a large cluster of cables.

European marking

Wire identification by color

The wire insulation is painted along the entire length in one color, or color marks are applied. The standard defines the order in which the markup for certain colors is applied.

For green and yellow colors, only their combination on the marking of one shell is allowed. Separate marking with these colors is prohibited. This color marking serves to identify protected conductors.

A light blue color is used to highlight the middle conductors. The electrical wires of the phases are marked in black, gray and brown.

Identification of wire insulation using letters and numbers

Such marking methods define the constituent parts of wire and cable designs. But they do not have a complete list of information about the wires. Such information should be sought in specialized literature.