A brief overview of the symbols used in electrical circuits. Color codes for phase L, zero N and ground What l and n mean when connected

When working with electricity, you can see that the strands of wires are painted in different colors. Interestingly, the colors never repeat, regardless of the number of conductors in one sheath. Why this is done and how not to get confused in the color variety - this is our today's article.

The essence of the color marking of wires

Working with electricity is a serious matter, because there is a risk of damage electric shock. It is not so easy for a simple person to cope with, because by cutting the cable, you can see that all the cores have a different color. This approach is not an invention of manufacturers in order to distinguish their products from competitors, but is very important when installing electrical wiring. To avoid confusion with the color of the cable cores, all the variety of colors is reduced to one standard - PUE. The electrical installation rules state that wire cores must be differentiated by color or alphanumeric designation.

Color marking allows you to determine the purpose of each wire, which is extremely important when switching. Correct connection lived among themselves, as well as during the installation of wiring accessories, helps to avoid serious consequences such as a short circuit, electric shock, or even a fire. Properly connected wires help to subsequently carry out repairs and maintenance without problems.

According to the rules, the color of the wires is present along the entire length. However, in reality, you can find electrical wires painted in one color. Most often this is found in the old housing stock, where aluminum wiring. To solve problems with the color designation of each individual core, a heat-shrinkable tube or electrical tape of different colors is used: black, blue, yellow, brown, red, etc. Multi-color marking is done at the junction points of the wires and at the ends of the cores.

Before talking about the color difference, it is worth mentioning the designation of wires with letters and numbers. Phase conductor in a single-phase network alternating current denoted Latin letter"L" (Line). In a three-phase circuit, phases 1, 2 and 3 will be respectively designated "L1", "L2", "L3". The grounding phase conductor is designated by the abbreviation "LE" in a single-phase network and "LE1", "LE2", "LE3" in a three-phase network. The neutral wire is assigned the letter "N" (Neutral). The neutral or protective conductor is designated "PE" (Protect Earth).

Ground wire color code

According to the rules for the use of electrical equipment, all of it must be connected to a network that has a ground wire. It is in this situation that the manufacturer's warranty will apply to the equipment. According to the PUE, the protection is in a yellow-green shell, and the color stripes must be strictly vertical. In a different location, such products are considered non-standard. Often you can find cores with a sheath of bright yellow or green color in the cable. In this case, they are used as grounding.

Interesting! Rigid single-core ground wire painted in green color with a thin yellow stripe, but in a soft stranded one, on the contrary, yellow is used as the main one, and green acts as an additional one.

In some countries, it is allowed to install a ground conductor without a sheath, but if you come across a green- yellow color with a blue braid and the designation PEN, then in front of you is grounding, combined with neutral. You should be aware that the earth is never connected to the residual current devices located in the switchboard. The ground wire is connected to the ground bus, to the housing or the metal door of the switchboard.

On the diagrams, you can see a different designation of grounding, so to avoid confusion, we recommend that you use the following memo:

A separate color for the neutral wire and a variety of colors for the phase

As evidenced by the PUE, for the neutral wire, which is often called zero, a single color designation is allocated. This color is blue, and it can be bright or dark and even blue - it all depends on the manufacturer. Even on color schemes, this wire is always drawn in blue. In the switchboard, the neutral is connected to the neutral bus, which is connected to the meter directly, and not using the machine.

According to GOST, the colors of the phase wires can have any color except for blue, yellow and green, since these colors refer to zero and ground. This approach helps to distinguish the phase wire from the rest, since it is the most dangerous at work. Current flows through it, so it is extremely important to provide the correct designation in order to work safely. Most often, phase cores in a three-core cable are indicated in black or red. The PUE does not prohibit the use of other colors, with the exception of colors intended for zero and earth, therefore, sometimes you can find a phase core in the following shells:

• brown;
• gray;
• purple;
• pink;
• white;
• orange;
• turquoise.

If the colors are mixed up

We have given the basic rules for marking L, N, PE lived in an electrician by color, but it often happens that not all craftsmen follow the rules for installing electrical wiring. Among other things, there is a possibility that the electrical wires with a different color of the phase core or even a single-color cable have changed. How not to make a mistake in such a situation and make the correct designation of zero, phase and ground? best options in this case, the wires will be labeled according to their purpose. Required with the help of cambric ( heat shrink tubing) designate all elements that depart from switchboard and follow to the dwelling. The work may take a long time, but it's worth it.

To work on identifying the ownership of the cores, an indicator screwdriver is used - this is the simplest tool, which is elementary to use for subsequent marking of the phases. We take the device and with its metal tip we touch the bare (!) Core. The indicator on the screwdriver will only light up if you have found a phase wire. If the cable is two-core, then there should be no more questions, because the second conductor is zero.

Important! Any electrical cable always has L and N cores, regardless of the number of wires inside.

If a three-wire wire is being examined, a multimeter is used to find the ground and neutral wires. As you know, there may be electricity in the neutral conductor, but its doses will hardly exceed 30V. To measure on the multimeter, you must set the AC voltage measurement mode. After that, with one probe they touch the phase conductor, which was determined with the help of an indicator screwdriver, and with the second - to the remaining ones. Conductor showing smallest value on the instrument will be zero.

If it turned out that the voltage in the remaining wires is the same, you must use the resistance measurement method, which will determine the ground. For work, only cores will be used, the purpose of which is unknown - the phase wire is not involved in the test. The multimeter is switched to the resistance measurement mode, after which one probe touches a deliberately grounded and cleaned to metal element (this can be, for example, a heating battery), and the second probe touches the wires. Ground should not exceed 4 ohms while neutral will be higher.

In most modern cables, the conductors are insulated different colors. These colors have certain value and are not just chosen. What is the color marking of wires and how to use it to determine where zero and ground are, and where is the phase, and we will talk further.

In electrics, it is customary to distinguish wires by color. This greatly simplifies and speeds up the work: you see a set of wires of different colors and, by color, you can guess which one is intended for what. But, if the wiring is not factory and it was not you who did it, before starting work, you must definitely check whether the colors correspond to the intended purpose.

To do this, they take a multimeter or tester, check the presence of voltage on each conductor, its magnitude and polarity (this is when checking the power supply network) or simply call where and where the wires come from and whether the color changes “on the way”. So knowing the color marking of wires is one of the necessary skills of a home craftsman.

Ground wire color code

By latest rules wiring in a house or apartment must be grounded. Last years all household and construction machinery Supplied with ground wire. Moreover, the factory warranty is preserved only if the power supply is supplied with a working ground.

In order not to be confused, it is customary to use a yellow-green color for the ground wire. A rigid single-core wire has a green base color with a yellow stripe, and a soft stranded wire has a main field of yellow color with a green longitudinal stripe. Occasionally there may be instances with horizontal stripes or just green, but this is not a standard.

Ground wire color - solid and stranded

Sometimes there is only bright green or yellow wire. In this case, it is they who are used as "earthen". On diagrams, "earth" is usually drawn in green. On the equipment, the corresponding contacts are signed in Latin letters PE or in the Russian version they write "earth". A graphic image is often added to the inscriptions (in the figure below).

In some cases, on the diagrams, the ground bus and the connection to it are indicated in green

Neutral color

Another conductor that is highlighted in a certain color is neutral or “zero”. Allotted for him blue color(bright blue or dark blue, occasionally blue). On color schemes, this circuit is also drawn in blue, signed with the Latin letter N. The contacts to which the neutral must be connected are also signed.

Neutral color - blue or light blue

In cables with flexible stranded wires As a rule, lighter shades are used, and solid solid conductors are sheathed in darker, more saturated tones.

Phase color

With phase conductors, it is somewhat more complicated. They are dyed in different colors. Excluded are already used - green, yellow and blue - and all the rest can be present. When working with these wires, you must be especially careful and attentive, because it is on them that voltage is present.

Wire color coding: what color is the phase - possible options

So, the most common color marking of phase wires is red, white and black. It can also be brown, turquoise orange, pink, purple, gray.

On the diagrams and terminals, phase wires are signed with the Latin letter L, in multi-phase networks there is a phase number next to it (L1, L2, L3). On cables with several phases, they have a different color. It's easier when distributing.

How to determine if the wires are connected correctly

When trying to install an additional outlet, connect a chandelier, household appliances, you need to know which wire is phase, which is zero, and which is grounding. If the connection is incorrect, the equipment fails, and careless touching of current-carrying wires can end sadly.

You need to make sure that the colors of the wires - ground, phase, zero - match their wiring

The easiest way is to navigate by the color marking of the wires. But it's not always easy. Firstly, in old houses, the wiring is usually monophonic - two or three white or black wires stick out. In this case, you need to understand specifically, and then hang tags or leave color marks. Secondly, even if the conductors in the cable are colored in different colors, and you can visually find the neutral and ground, you need to check the correctness of your assumptions. It happens that during installation the colors are mixed up. Therefore, we first double-check the correctness of the assumptions, then we begin work.

To check, you will need special tools or measuring instruments:

• indicator screwdriver;
• multimeter or tester.

You can find the phase wire using an indicator screwdriver; you will need a tester or multimeter to determine zero and neutral.

Checking with an indicator

Indicator screwdrivers are of several types. There are models on which the LED lights up when a metal part touches live parts. In other models, an additional press of a button is required for verification. In any case, when voltage is present, the LED lights up.

Using an indicator screwdriver, you can find the phases. metal part touch the bare conductor (if necessary, press the button) and see if the LED is on. Lit - this is a phase. Off - neutral or ground.

We work carefully, with one hand. The second one does not touch walls or metal objects (pipes, for example). If the wires in the cable under test are long and flexible, you can hold them with your other hand by the insulation (keep away from the bare ends).

Checking with a multimeter or tester

We set the scale on the device, which is slightly larger than the estimated voltage in the network, connect the probes. If we call a household single-phase network 220V, we put the switch in the 250 V position. With one probe we touch the bare part of the phase wire, the second - to the intended neutral (blue). If at the same time the arrow on the device deviates (we remember its position) or a number close to 220 V lights up on the indicator. We perform the same operation with the second conductor - which was identified as “ground” by color. If everything is correct, the readings of the device should be lower - less than those that were before.

If there is no color marking of the wires, you will have to sort through all the pairs, determining the purpose of the conductors according to the readings. We use the same rule: when the “phase-ground” pair rings, the readings are lower than when the “phase-zero” pair rings.

During self installation and connecting electrical equipment (this can be various lamps, ventilation, electric stoves, etc.), you can see that the switching terminals are marked with the letters L, N, PE. Of particular importance here is the marking L and N. In addition to the designation of wires in an electrician by letter, they are placed in insulation of various colors.

This greatly simplifies the procedure for determining where the phase, ground or neutral wire is located. In order for the device to be installed to work in normal mode, each of these wires must be connected to the appropriate terminal.

Designation of wires in an electrician by letters

Electrical communications in the domestic and industrial sectors are organized by means of insulated cables, inside of which there are conductive cores. They differ from each other in the color of the insulation and marking. The designation of l and n in electrics makes it possible to expedite the implementation of installation and repair measures by an order of magnitude.

The application of this marking is regulated by a special GOST R 50462: this applies to electrical installations where voltage up to 1000 V.

As a rule, they are equipped with a dead-earthed neutral. Often electrical equipment of this type have residential, administrative and economic facilities. During installation electrical networks in buildings of this type, it is necessary to be well versed in color and letter indications.

Phase designation (L)

The AC network includes live wires. Their correct name is "phase". This word has English roots, and is translated as "line" or "active wire". Phase conductors carry a particular danger to human health and property. For safe operation they are covered with reliable insulation.

The use of bare wires under voltage is fraught with the following consequences:

1. 1. Electric shock to people. These can be burns, injuries, and even death.
2. 2. The occurrence of fires.
3. 3. Equipment damage.

At designation of wires in electrical phase conductors are marked with the letter "L". This is an abbreviation of the English term " Line", or " line"(Another name for phase wires).

There are other versions of the origin of this marking. Some experts believe that the words “Lead” (supply conductor) and Live (indication of voltage) became the prototype. A similar marking is also used to indicate the clamps and terminals to which the line wires should be switched. For example, in three-phase networks, each of the lines is also marked with the corresponding number (L1, L2 and L3).

The current domestic regulations governing the designation of phase and zero in electrics (GOST R 50462-2009) require that linear conductors be placed in brown or black insulation. Although in practice the phase wires can be white, pink, gray, etc. In this case, it all depends on the manufacturer and the insulating material.

Zero notation (N)

To mark the neutral or zero working core of the network, use the letter "N". This is an abbreviation of the term neutral(translated as neutral). So all over the world it is customary to call the zero conductor. In our country, the word “Zero” is mainly used.

Most likely, the word Null is taken as the basis here. The letter "N" in the diagram indicates the contacts or terminals intended for switching the neutral core. A similar designation is accepted for both single-phase and three-phase circuits. As a color designation for the neutral wire, blue or white-blue (white-blue) insulation is used.

Earth symbol (PE)

In addition to the designation of phase and zero, a special letter designation PE (Protective Earthing) is also used in electrics for the ground wire. As a rule, they are always included in the cable, along with zero and phase conductors. Contacts and clamps intended for switching with a grounding neutral wire are also marked in a similar way.

For ease of installation, the conductors for grounding are placed in yellow-green insulation. House master must understand that these colors always indicate only ground wires. To indicate phase and zero in electrics, yellow and green are never used.

As practice shows, when organizing electrical networks in buildings of the residential sector, violations of the generally accepted standards for the use of insulation color and the corresponding alphanumeric marking are sometimes allowed. In this case, it is not always enough to have the ability to decipher the designations L, N or PE.

In order for the connection of electrical equipment to be truly safe, it is necessary to check the conformity of the marking with the real state of affairs. To do this, use special devices (testers) or improvised devices. In the absence of experience in such work, for your own safety, it is better to invite an experienced electrician with the appropriate approval.

The designation of l and n in electrics

Designation of phase and zero in electrics introduced to ensure that electrical networks are safe and convenient to use. For this, a special letter marking (l and n) and insulation of the corresponding color. There may also be PE-marked cores in yellow-green color: this is how the ground wires are marked.

In addition, the same letter designations are used on the connecting contacts and terminals. All that needs to be done during the installation of the electrical appliance is to bring each of the wires to the terminal. For reinsurance, it is advisable to check each of the wires with a tester.

The vast majority of cables have different colors of core insulation. This was done in accordance with GOST R 50462-2009, which establishes the l n marking standard in electrics (phase and neutral wires in electrical installations). Compliance with this rule guarantees quick and safe work of the master at a large industrial facility, and also allows you to avoid electrical injuries during self-repair.

Variety of colors for electrical cable insulation

The color coding of wires is diverse and varies greatly for grounding, phase and neutral conductors. To avoid confusion, the requirements of the PUE regulate what color of the ground wire to use in the power panel, what colors must be used for zero and phase.

If a installation work carried out by a highly qualified electrician who knows modern standards for working with electrical wires, you do not have to resort to using an indicator screwdriver or a multimeter. The purpose of each cable core is deciphered by knowing its color designation.

Ground wire color

From 01/01/2011, the color of the ground (or neutral) conductor can only be yellow-green. This color marking of wires is also observed when drawing up diagrams on which such cores are signed in Latin letters PE. Not always on cables, the coloring of one of the cores is intended for grounding - usually it is done if there are three, five or more cores in the cable.

PEN-wires with combined "ground" and "zero" deserve special attention. Connections of this type are still often found in old buildings, in which electrification was carried out according to outdated standards and has not yet been updated. If the cable was laid according to the rules, then the blue color of the insulation was used, and yellow-green cambric was put on the ends and joints. Although, you can also find the color of the ground wire (grounding) exactly the opposite - yellow-green with blue tips.

The ground and neutral conductors may differ in thickness, often it is thinner than the phase ones, especially on cables that are used to connect portable devices.

Protective grounding is mandatory when laying lines in residential and industrial premises and is regulated by the PUE and GOST 18714-81 standards. The zero ground wire should have as little resistance as possible, the same applies to the ground loop. If all installation work is done correctly, then grounding will be a reliable protector of human life and health in the event of a power line malfunction. As a result, the correct marking of cables for grounding is critical, and grounding should not be used at all. All new houses are wired according to the new rules, and the old ones are queued for replacement.

Colors for neutral wire

For "zero" (or zero working contact), only certain colors wires are also strictly defined by electrical standards. It can be blue, blue or blue with a white stripe, and regardless of the number of cores in the cable: a three-core wire in this regard will not differ in any way from a five-core one or with more large quantity conductors. In electrical circuits, “zero” corresponds to the Latin letter N - it participates in closing the power supply circuit, and in circuits it can be read as “minus” (phase, respectively, is “plus”).

Colors for phase conductors

These electrical wires require special care and "respectful" handling, as they are current-carrying, and careless contact can cause severe electric shock. The color marking of wires for connecting the phase is quite diverse - you cannot use only colors adjacent to blue, yellow and green. To some extent, it is much more convenient to remember what the color of the phase wire can be - NOT blue or blue, NOT yellow or green.

On electrical diagrams, the phase is denoted by the Latin letter L. The same marking is used on wires if color marking is not used on them. If the cable is designed to connect three phases, then the phase conductors are marked with the letter L with a number. For example, to create a diagram for three-phase network 380 V used L1, L2, L3. Even in electrics, an alternative designation is accepted: A, B, C.

Before starting work, you need to decide how the combination of wires will look in color and strictly adhere to the chosen color.

If this question was thought out at the stage preparatory work and taken into account when drawing up wiring diagrams, you should purchase required amount cables with conductors of the required colors. If nevertheless desired wire is over, you can manually mark the wires:

• ordinary cambric;
• shrink tubes;
• tape.

About wire color marking standards in Europe and Russia, see also in this video:

Manual color marking

It is used in cases where during installation it is necessary to use wires with conductors of the same color. It also often happens when working at home. old building, in which the installation of electrical wiring was carried out long before the advent of standards.

Experienced electricians, so that there is no confusion during further maintenance of the electrical circuit, used kits that allow you to mark the phase wires. This is allowed and modern rules, because some cables are made without color-letter designations. The place of use of manual marking is regulated by the norms of the PUE, GOST and generally accepted recommendations. It is attached to the ends of the conductor, where it connects to the bus.

Marking two-wire wires

If the cable is already connected to the network, then a special indicator screwdriver is used to search for phase wires in an electrician - there is an LED in its case that glows when the sting of the device touches the phase.

True, it will be effective only for two-wire wires, because if there are several phases, then it will not be able to determine where which indicator is. In this case, you will have to disconnect the wires and use a continuity.

Standards do not oblige to make such markings on electrical conductors along their entire length. It is allowed to mark it only at the joints and connections of the necessary contacts. Therefore, if it becomes necessary to apply labels on electrical cables without designations, you need to purchase materials in advance for marking them manually.

The number of colors used depends on the scheme used, but the main recommendation is still there - it is desirable to use colors that exclude the possibility of confusion. Those. do not use blue, yellow or green labels for phase wires. In a single-phase network, for example, the phase is usually indicated in red.

Three-core wire marking

If you need to determine the phase, zero and ground in three-wire wires, then you can try to do this with a multimeter. The device is set to measure AC voltage, and then gently touch the phase with the probes (it can be found and indicator screwdriver) and in series the two remaining wires. Next, you should remember the indicators and compare them with each other - the “phase-zero” combination usually shows a greater voltage than “phase-ground”.

When the phase, zero and earth are determined, then marking can be applied. According to the rules, a yellow-green colored wire is used for grounding, or rather a core with such a color, so it is marked with electrical tape suitable colors. Zero is marked, respectively, with blue electrical tape, and the phase is any other.

If at preventive work it turned out that the marking was outdated, it was not necessary to change the cables. Replacement, in accordance with modern standards, is subject only to electrical equipment that has failed.

As a result

Correct marking of wires is a prerequisite for high-quality installation of electrical wiring when carrying out work of any complexity. It greatly facilitates both the installation itself and the subsequent maintenance of the electrical network. To make electricians "speak the same language", created mandatory standards color-letter markings, which are similar to each other even in different countries. In accordance with them, L is the designation of the phase, and N is zero.

Important for faster and correct installation electrical distribution devices, ease of repair and elimination of errors. The colors of the wires in the electrician are regulated normative documents(PUE and GOST R 50462-2009).

Why color coding of wires and cables is needed

Installation and maintenance work in electrical installations related not only to reliability, but also to safety. Full error elimination is required. For these purposes, a system of color designations for core insulation has been developed, which determines what color the wires are phase, zero and earth.

According to the PUE, the following colors of current-carrying conductors are allowed:

• red;
• brown;
• black;
• gray;
• white;
• pink;
• orange;
• turquoise;
• purple.

The list below contains many wire color options, but there are not several colors that are used only to designate neutral and protective wires:

• blue color and its shades - working neutral wire (neutral - N);
• yellow with green stripe - protective earth (PE);
• yellow-green insulation with blue marks on the ends of the cores - combined (PEN) conductor.

It is allowed to use for grounding conductors with green insulation with a yellow stripe, and for combined conductors of blue insulation with yellow-green marks at the ends.

The colors must be the same in each circuit within the same device. Branch circuits must be carried out with the same colored conductors. The use of isolation without differences in shades indicates high culture installation and greatly facilitates further maintenance and repair of equipment.

Phase color

In cases where the installation of the electrical installation is carried out using rigid metal tires, the tires are painted with indelible paint in the following colors:

• yellow - phase A (L1);
• green - phase B (L2);
• red - phase C (L3);
• blue - zero bus;
• longitudinal or inclined stripes of yellow and green color - ground bus.

The color of the phases must be preserved within the entire device, but not necessarily on the entire surface of the tire. It is allowed to mark the phase designation only at the connection points. On the painted surface, you can duplicate the color with the symbols “GZK” for the paint of the corresponding colors.

If the tires are not available for inspection or work when voltage is present on them, then it is allowed not to paint them.

The color of the phase wires connected to the rigid busbars may not match them in color, since the difference in the accepted designation systems for flexible conductors and rigid stationary distribution busbars is visible.

Neutral color

What color is the neutral wire, stipulate GOST standards, so when looking at the installation of the power plant, the question should not arise, blue wire- this is a phase or zero, since the blue color and its shades (blue) are taken to indicate the neutral (working ground).

Other neutral core colors are not permitted.

The only acceptable use of blue and blue insulation is the designation of a negative pole or midpoint in circuits direct current. You can't use this color anywhere else.

Ground wire color code

Regulations specify what color the earth wire is in electrical installations. This is a yellow-green wire, the color of which stands out well from the rest of the wires. It is allowed to use wire with yellow insulation and a green stripe on it, or it can be green insulation with a yellow stripe. No other color of ground wire is permitted, nor are green/yellow conductors permitted to be used in circuits where voltage is present or may be energized.

The listed marking rules are observed in the countries of the post-Soviet space and in the EU countries. Other states mark the cores in a different way, which can be seen on imported equipment.

Basic colors for marking abroad:

• neutral - white, gray or black;
• protective earth - yellow or green.

The standards of a number of countries allow the use of bare metal without insulation as a protective ground.

Ground wires are switched on prefabricated non-insulated terminals and interconnect all metal parts of the structure that do not have reliable electrical contact with each other.

Coloring in the network 220V and 380V

Installation of one- and three-phase electrical networks is facilitated if the wiring is made with multi-colored wire. Previously, flat two-core wire was used for single-phase apartment wiring. white color. During installation and repair, in order to eliminate errors, it was necessary to ring each core separately.

Production of cable products with coloring of cores different colors reduces labor intensity. To designate phase and zero in single-phase wiring, it is customary to use the following colors:

• red, brown or black - phase wire;
• other colors (preferably blue) - neutral wire.

Phase marking in a three-phase network is slightly different:

• red (brown) - 1 phase;
• black - 2 phase;
• gray (white) - 3 phase;
• blue (cyan) - working zero (neutral)
• yellow-green - grounding.

Domestic cable products comply with the core color standard, so a multi-phase cable contains multi-colored cores, where the phase is white, red and black, zero is blue, and the ground is yellow-green conductors.

When servicing networks mounted according to modern standards, you can accurately determine the purpose of the wires in junction boxes. If there is a bundle of multi-colored wires, the brown one will necessarily be phase. The neutral wire in the distribution boxes has no branches and breaks. The exception is taps to multi-pole switching devices with a complete opening of the circuit.

Coloring in DC networks

For DC networks, it is customary to mark the conductors connected to the positive pole in red, to the negative - in black or blue. In bipolar circuits, isolation blue tint used when marking the midpoint (zero) of power.

There are no standards for color markings in multi-voltage circuits. What color are the plus and minus wires, what voltage is in them - this can only be determined by decoding the device manufacturer, which is often given in the documentation or on one of the walls of the structure. Example: computer power supply or car wiring.

Automotive wiring is characterized by the fact that in it the circuits with a positive voltage of the on-board network are red or its shades (pink, orange), and those connected to ground are black. The rest of the wires have a specific color, which is determined by the car manufacturer.

Letter designation of wires

Color marking can be supplemented with letters. Partially, the symbols for designation are standardized:

• L (from the word Line) - phase wire;
• N (from the word Neutral) - neutral wire;
• PE (from a combination of Protective Earthing) - grounding;
• “+” – positive pole;
• “-” – negative pole;
• M - middle point in DC circuits with bipolar power supply.

To designate the protective earth connection terminals, a special symbol is used, which is stamped on the terminal or on the instrument case in the form of a sticker. The ground symbol is the same for most countries in the world, which reduces the likelihood of confusion.

In multi-phase networks, the symbols are supplemented by the phase serial number:

• L1 is the first phase;
• L2 - second phase;
• L3 is the third phase.

There is marking according to old standards, when the phases are denoted by the symbols A, B and C.

A deviation from the standards is the combined phase designation system:

• La is the first phase;
• Lb is the second phase;
• Lc is the third phase.

In complex devices, there may be additional designations characterizing the name or number of the circuit. It is important that the markings of the conductors match throughout the entire circuit where they participate.

The letter designations are applied with indelible, clearly visible paint on the insulation near the ends of the cores, on pieces of PVC insulation or heat-shrinkable tubing.

Connection terminals may have printed signs that indicate the circuits and polarities of the power supply. Such signs are made by paint, stamping or etching, depending on the material used.