Designations of phase and zero in electrical engineering. Schematic designation of phase and zero in English L n what is plus

RozetkaOnline.ru - Home electrical: articles, reviews, instructions!

Designation L and N in electrics

Every time you try to connect a chandelier or sconce, a light or motion sensor, hob or exhaust fan, floor heating thermostat or power supply LED strip, as well as any other electrical equipment, you can see the following markings near the connection terminals - L and N.

Let's figure out what the designations L and N mean in electrical engineering.

As you probably guessed, these are not just arbitrary symbols, each of them carries a specific meaning and serves as a hint for correct connection electrical appliance to the network.

Designation L in electrical

“L” - This marking came to electrical engineering from the English language, and it is formed from the first letter of the word “Line” (line) - the generally accepted name for a phase wire. Also, if it is more convenient for you, you can focus on such concepts of English words as Lead (lead wire, core) or Live (under voltage).

Accordingly, the designation L marks the clamps and contact connections intended for connecting the phase wire. In a three-phase network, alphanumeric identification (marking) of phase conductors “L1”, “L2” and “L3”.

By modern standards ( GOST R 50462-2009 (IEC 60446:2007), valid in Russia, the colors of the phase wires are brown or black. But often, there may be white, pink, gray or a wire of any other color except blue, white-blue, cyan, white-blue or yellow-green.

Designation N in electrical

“N” is a marking formed from the first letter of the word Neutral (neutral) - the generally accepted name for the neutral working conductor, in Russia more often called simply the neutral conductor or briefly Zero (Zero). In this regard, it is well suited English word Null (zero), you can focus on it.

In electrical engineering, the designation N marks clamps and contact connections for connecting the neutral working conductor/neutral wire. Moreover, this rule applies to both single-phase and three-phase networks.

The colors of the wire that mark the neutral wire (zero, zero, zero working conductor) are strictly blue (light blue) or white-blue (white-blue).

Grounding Designation

If we are talking about the designations L and N in electrics, we cannot help but note this sign - which can also almost always be seen together with these two markings. This icon marks clamps, terminals or contact connections for connecting wires protective grounding(PE - Protective Earthing), also known as neutral protective conductor, grounding, earth.

Generally accepted color coding neutral protective wire – yellow-green. These two colors are reserved only for ground wires and are not used to designate phase or neutral wires.

Unfortunately, often the electrical wiring in our apartments and houses is not carried out in compliance with all strict standards and rules for color and alphanumeric markings for electricians. And knowing the purpose of the L and N markings on electrical equipment is sometimes not enough for proper connection. Therefore, be sure to read our article “How to determine phase, zero and grounding yourself, using improvised means? “If you have any doubts, this material will come in handy.

Join our VKontakte group!

http://rozetkaonline.ru

When working with electricity, you may notice that the wire strands are colored different colors. Interestingly, the colors are never repeated regardless of the number of conductors in one shell. Why this is done and how not to get confused in the color variety - this is what our article is about today.

The essence of color coding of wires

Working with electricity is a serious matter, as there is a risk of injury electric shock. It is not so easy for an ordinary person to deal with, because when you cut the cable, you can see that all the wires 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 cable cores, all the variety of colors has been reduced to one standard - PUE. Electrical installation rules state that wire cores must be differentiated by color or alphanumeric designation.

Color coding allows you to determine the purpose of each wire, which is extremely important when switching. Correct connection of cores to each other, as well as during installation electrical installation products, helps to avoid serious consequences such as short circuit, electric shock or even fire. Properly connected wires help 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 occurs in old housing stock where aluminum wiring is installed. To solve problems with the color designation of each individual core, heat-shrinkable tubing or electrical tape of different colors is used: black, blue, yellow, brown, red, etc. Multi-colored markings are made at the connection points of the wires and at the ends of the wires.

Before talking about color differences, it is worth mentioning the designation of wires with letters and numbers. Phase conductor in a single-phase network alternating current denoted by the Latin letter "L" (Line). In a three-phase circuit, phases 1, 2 and 3 will be designated “L1”, “L2”, “L3” respectively. 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 standards 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 consists of a yellow-green shell, and the color stripes must be strictly vertical. With a different arrangement, such products are considered non-standard. You can often find wires in a cable with a bright yellow or green sheath. In this case, they are used as grounding.

Interesting! Hard solid wire grounding is painted green with a thin yellow stripe, but in soft stranded, on the contrary, yellow is used as the main one, and green acts as an additional one.

In some countries, installation of a grounding conductor without a sheath is allowed, but if you come across a green cable, yellow color with a blue braid and the designation PEN, then you have a grounding combined with a neutral. You should know that the ground is never connected to the residual current devices located in the distribution panel. The grounding wire is connected to the grounding bus, to the housing or metal door of the switchboard.

On the diagrams you can see different grounding symbols, so to avoid confusion, we recommend that you use the following reminder:

Separate color for the neutral wire and a variety of colors for the phase wire

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

According to GOST, the colors of the phase wires can have any color with the exception of blue, yellow and green, since these colors relate to zero and grounding. This approach helps to distinguish the phase wire from the rest, since it is the most dangerous during operation. It carries current, so it is extremely important to ensure it is properly labeled to ensure safe operation. Most often, the phase conductors 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 ground, so sometimes you can find a phase conductor 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 conductors in electrical wiring 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 have changed with a different color of the phase core or even a single-color cable. How not to make a mistake in such a situation and make the correct designation of zero, phase and grounding? Best options in this case, the wires will be marked according to their purpose. It is necessary with the help of cambrics ( heat shrink tubing) designate all elements that extend from the distribution panel and enter the home. The work may take a long time, but it is worth it.

To work to identify the identity of the veins, use indicator screwdriver- this is the simplest tool, which is easy to use for subsequent marking of phases. We take the device and with its metal tip touch the bare (!) conductor. The indicator on the screwdriver will light up only 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-core wire is being examined, a multimeter is used to find the ground and neutral wires. As is known, electricity may be present in the neutral conductor, but its doses will barely exceed 30V. To measure on the multimeter, you must set the AC voltage measurement mode. After this, use one probe to touch the phase conductor, which was determined using indicator screwdriver, and the second - to the remaining ones. The conductor who showed smallest value on the device will be zero.

If it turns out that the voltage in the remaining wires is the same, you need to use the resistance measurement method, which will allow you to determine the ground. Only conductors whose purpose is unknown will be used for work - the phase wire is not involved in the test. The multimeter is switched to the resistance measurement mode, after which one probe touches an element that is known to be grounded and cleaned to metal (this could be, for example, a heating battery), and the second touches the conductors. The ground should not exceed a reading of 4 ohms, while the neutral will have a higher reading.

In progress self-installation and connecting electrical equipment (this could be various lamps, ventilation, electric stoves, etc.), you will notice that the switching terminals are marked with the letters L, N, PE. The markings L and N are of particular importance here. In addition to marking the wires in electrics by letter, they are placed in insulation of different colors.

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

Designation of wires in electrics by letter

Electrical communications in the domestic and industrial spheres are organized through insulated cables, inside of which there are conductive cores. They differ from each other in insulation color and markings. Designation l and n in electrics makes it possible to speed up the implementation of installation and repair activities 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 solidly grounded neutral. Often residential, administrative and business facilities have electrical equipment of this type. When installing electrical networks in buildings of this type, it is necessary to have a good understanding of color and letter instructions.

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 pose a particular danger to human health and property. For safe operation they are covered with reliable insulation.

The use of exposed live wires is fraught with the following consequences:

1. 1. Electric shock to people. This can result in burns, injuries and even death.
2. 2. The occurrence of fires.
3. 3. Damage to equipment.

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 prototype was the words “Lead” (lead wire) and Live (indication of voltage). Similar markings are also used to indicate the clamps and terminals to which the linear wires must be connected. For example, in three-phase networks, each line is also marked with a corresponding number (L1, L2 and L3).

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

Zero designation (N)

For marking neutral or zero working core networks use the letter "N". This is an abbreviation of the term neutral(translated as neutral). This is what is commonly called the neutral conductor all over the world. In our country, the word “Zero” is mostly used.

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

Grounding symbol (PE)

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

For ease of installation, the grounding conductors are placed in yellow-green insulation. Home master Please note that these colors always indicate the ground wires only. Yellow and green are never used to indicate phase and zero in electrical engineering.

As practice shows, when organizing electrical networks in residential buildings, violations of generally accepted standards for the use of insulation color and corresponding alphanumeric markings 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 whether the markings correspond to the actual state of things. To do this, use special devices (testers) or improvised devices. In the absence of experience in such work for own safety It is better to invite an experienced electrician with the appropriate permit.

Designation l and n in electrics

Designation of phase and zero in electrical engineering introduced to ensure that electrical networks are safe and easy to use. For this purpose, a special letter marking (l and n) and insulation of the appropriate color. There may also be conductors marked PE in yellow-green color: this is how grounding wires are designated.

In addition, these same letter designations used on connecting contacts and terminals. All that needs to be done when installing an electrical appliance is to connect each of the wires to the terminal. To be on the safe side, it is advisable to check each of the wires with a tester.

The ability to read electrical diagrams is an important component, without which it is impossible to become a specialist in the field electrical installation work. Every novice electrician must know how sockets, switches, switching devices and even an electricity meter are designated on a wiring project in accordance with GOST. Next, we will provide readers of the site with symbols in electrical diagrams, both graphic and alphabetic.

Graphic

As for the graphic designation of all elements used in the diagram, we will provide this overview in the form of tables in which the products will be grouped by purpose.

In the first table you can see how electrical boxes, panels, cabinets and consoles are marked on electrical circuits:

The next thing you should know is symbol power sockets and switches (including walk-through ones) on single-line diagrams of apartments and private houses:

As for lighting elements, lamps and fixtures according to GOST are indicated as follows:

In more complex circuits where electric motors are used, elements such as:

It is also useful to know how transformers and chokes are graphically indicated on circuit diagrams:

Electrical measuring instruments according to GOST have the following graphic designation on the drawings:

By the way, here is a table useful for novice electricians, which shows what the ground loop looks like on a wiring plan, as well as the power line itself:

In addition, in the diagrams you can see a wavy or straight line, “+” and “-”, which indicate the type of current, voltage and pulse shape:

In more complex automation schemes, you may encounter incomprehensible graphic symbols, such as contact connections. Remember how these devices are designated on electrical diagrams:

In addition, you should be aware of what radio elements look like on projects (diodes, resistors, transistors, etc.):

That's all the conventional graphic symbols in the electrical circuits of power circuits and lighting. As you have already seen for yourself, there are quite a lot of components and remembering how each is designated is possible only with experience. Therefore, we recommend that you save all these tables so that when reading the wiring plan for a house or apartment, you can immediately determine what kind of circuit element is located in a certain place.

Interesting video

In order to facilitate the installation of electrical wiring, all cable and wire products have appropriate multi-colored markings. As a rule, in houses or apartments, lighting is installed and sockets are connected using three wires. Each of them has its own purpose in the home electrical network. Therefore, the designation of the color of the ground wires has great importance. Due to this, installation time and subsequent repairs are significantly reduced. Thanks to color coding, any type of connection is not particularly difficult.

Ground wire

In most cases, the color yellow-green is used to indicate the ground wire. Sometimes you can find conductors with only yellow insulation. Even less commonly used light green color. Typically, such wires are marked with PE symbols. However, if the ground wire is aligned with the neutral, it is designated as PEN. It is colored green-yellow and has a blue braid at the ends.

In the distribution panel, the grounding wire is connected to a special busbar, or to the housing and metal door. IN distribution box the connection is made with similar wires provided in lamps and sockets equipped with special grounding contacts. The grounding wire does not need to be connected to a residual current device (RCD), therefore such protective devices used where only two wires are used for electrical wiring.

Neutral conductor (neutral)

The color blue is traditionally used for the neutral conductor or neutral. The connection in the distribution panel is made through a special zero bus, designated by the symbol N. All blue wires are connected to this bus.

The bus itself is connected to the input via. In some cases, the connection can be made directly, without any additional automatic devices.

All neutral wires in the junction box of blue color are connected together and do not take part in commutation. The exception is the wire coming from the switch. Connecting blue wires to sockets is done using a special zero contact, designated by the letter N. This marking is affixed to the back of each socket.

Phase wire color

The phase does not have any precise designation. Black, brown, red and other colors other than green, yellow and blue are quite common. In the distribution panel installed in the apartment, the connection of the phase wire coming from the consumer is made with a contact circuit breaker, located below. In other circuits, this conductor may be connected to a residual current device.

In switches, the phase is directly involved in switching. With its help, the contact is closed and opened - turned on and off. In this way, voltage is supplied to consumers, and, if necessary, this supply is stopped. In sockets, the phase conductor is connected to the contact marked L.

Wire Definition

Sometimes situations arise when it is necessary to determine the purpose of a particular wire if there is no marking on it. The simplest and most common way is. With its help, you can accurately determine which wire will be phase and which will be neutral. First of all, you need to turn off the power supply to the panel. After this, the ends of the two conductors are stripped and separated to the sides away from each other. Then you need to turn on the electricity supply and use the indicator to determine the purpose of each wire. If the light bulb lights up upon contact with the core, this is a phase. This means the other core will be neutral.

If there is a ground wire in the electrical wiring, it is recommended to use a multimeter. This device is equipped with two tentacles. First, the measurement of alternating current in the range of more than 220 volts is set at the appropriate mark. One tentacle is fixed at the end of the phase wire, and the second one determines grounding or zero. In case of contact with zero, the device display will display a voltage of 220 volts. When you touch the ground wire, the voltage will be noticeably lower.

Marking

There is not only the color of the wires phase, zero, ground, but also other types of markings, primarily alphabetic and digital designations. The first letter A indicates the wire material - aluminum. If this letter is missing, the core material will be copper.

Basic marking of wires in electrical engineering:

• AA - corresponds to stranded aluminum cable with additional braiding made of the same material.
• AC - additional lead braid.
• B - the presence of protection from moisture and additional braiding made of two-layer steel.
• BN - non-flammable cable braid.
• G - absence of a protective shell.
• R - rubber shell.
• HP - rubber shell made of non-flammable material.