Colors of conductors of a three-phase network. Phase and zero wire color: why marking is needed

There is a funny opinion among newbies in electrics that different colors of cables and wires are just an advertising "trick" of manufacturing companies. Of course, this is not true. Conductors differing in color are needed for convenience - in order to immediately determine: where is the phase in the wiring, where is zero and where is grounding.

At the same time, incorrect connection of incompatible types of wires is fraught not only with a short circuit, but also with electric shock to a person.

The main task of the tsyetovaya is to provide safe conditions electrical work. Insulation colors that differ from each other can significantly reduce the time it takes to find and connect certain contacts.

If you look at the PUE or the same European standards, you can find out that each individual core has its own special color of the insulating layer. The main objective of this article is to help the reader understand: what color are the phase, zero and ground wires.

Appearance of the ground wire

According to the rules for the installation of electrical installations, the insulating layer of the ground wire must be painted yellow-green. Sometimes manufacturing companies also apply a green insulating layer with longitudinal and transverse yellow stripes to the wire. There are also shells entirely painted in yellow or green. On the wiring diagram, the “earth” is marked with the abbreviation “PE”. What is important - the ground wire can be called "zero protection" and at the same time this definition should not be confused with the "neutral wire".

Example appearance"grounding":

Appearance of the neutral wire

Both single-phase and three-phase electrical network the color marking of the neutral wire must always be blue or blue. On the diagram, it is designated as "N". Also, zero is often called zero or neutral working contact.

An example of the appearance of "neutral":

The appearance of the wire "phase"

Unlike the previous versions of the conductors, the phase wire (aka “L”) can be painted in one of the following colors:

black;
white;
grey;
red;
brown;
orange;
Violet;
pink;
turquoise.

It is worth noting that often the “phase” is black, white or brown:

Important information

Color coding electrical wiring has many features. Often beginners are faced with a huge number of various issues. The most frequent among them:

What does the abbreviation "PEN" mean?
How to determine where the ground, zero and phase are, if the wires do not differ in insulation colors or have a non-standard color?
How to specify zero, phase and ground yourself?
What other wire color coding standards might exist?

Well, let's find answers to these important questions together.

Abbreviation "PEN"

The TN-C grounding system, which has become irrelevant at the present time, involves combining grounding with neutral. This has its own plus, which is to increase the ease of installation work. However, it also has its drawback, namely, the risk of electric shock when installing wiring in a house or apartment. In this case, such a combined wire is painted yellow-green, but the ends of the insulation are blue (which is typical for neutral). Just this combined contact is indicated on the diagrams as "PEN":

Search for PE, L and N

Suppose, in the process of repairing an electrical network, you find that all the wires are painted the same color. How to figure out what each of the conductors means?

If a single-phase network does not imply the presence of grounding (there are only two wires in the network), then an indicator screwdriver is needed. It will help to determine which of the wires is “phase” and which is “zero”.

Before the procedure, do not forget to turn off the power supply at the input panel. Next, you will need to carefully strip both wires of the network and separate them away from each other, after which, turn on the current supply again. Now it remains to distinguish the “phase” from “zero” using the indicator: upon contact with the “phase” wire, the light on the screwdriver handle will light up (from which it follows that the second wire is the desired “zero”).

In the same situation, when the wiring also has a third ground wire, you need to use a multimeter. In short, it is applied as follows. First, set the measurement range on the device alternating current above 220 volts. Next, lean one of the two tentacles against the phase core, and with the second tentacle, find “zero” / “ground”. In this case, in case of contact with the neutral conductor, the voltage value within 220 Volts will appear on the display of the multimeter. In the case of contact with the ground wire, the voltage will be slightly lower.

There is another way to determine the types of conductors. It will help you when there is neither an indicator screwdriver nor a multimeter at hand. The logic and color of the insulation will help out here. Remember that the blue shell is absolutely always "zero". Determining the remaining two wires will be a little more difficult. The first option is this: you are left with a colored and black / white contact, among which the colored one is most likely the “phase”, and the last white or black wire is the “ground”. A second scenario is also possible: you are left with a red and black / white wire, where white insulation (according to the PUE) means “phase”, and the remaining red one means “ground”.

Be careful! The described method is only advisory in nature and is quite dangerous. In case you decide to use it, make appropriate notes for yourself that will save you from electric shock when replacing a chandelier or socket.

What else I would like to say is that in the chain direct current color marking of plus and minus is represented by black and red color of the insulating layer. In a three-phase network, each “phase” will have its own color (A is yellow, B is green, and C is red). In this case, “zero” will be blue, and “ground” will be yellow-green. In a 380 volt cable, wire A will be white, B black, and C red. Zero working and protective wires will be the same as in the previous version.

How to specify L, N and PE by yourself?

When the designation does not exist at all, or it is radically different from the standard one, it is recommended to designate all the elements on your own. In this case, colored electrical tape or special heat-shrink tubing(also known as cambric). According to regulatory documents indication of the types of wires must be carried out at their ends - in those places where the conductors are connected to the bus:

The marks made will help in the future both the owner of the house or apartment, and the invited electrician. And this is really worth taking care of in advance.

There are, in fact, not many different types of conductors and their connections. In the electric power industry, a distinction is made between supply and protective conductors. Some have heard such words as "zero" and "phase" wire. However, this is where questions arise. How to determine zero and phase in a real network?

What are the conductors in the socket?

You can deal with the question "what is phase and zero" without delving into the wilds of finding out the structure, advantages and disadvantages in three-phase or five-phase circuits. You can actually disassemble everything on your fingers, revealing the most ordinary home socket, which is placed in an apartment or private house ten or fifteen years ago. As you can see, this socket is connected to two wires. How to determine zero and phase?

How do wires work in an outlet and why are they needed?

As you can see, there are certain differences between workers and zero. What is the designation of phase and zero? A bluish or blue color is the color of the phase wire, zero is indicated by any other colors, with the exception, of course, of blue colors. It can be yellow, green, black and striped. The current does not flow. If you take it and do not touch the worker, then nothing will happen - there is no potential difference on it (in fact, the network is not ideal, and there may still be a small voltage, but it will be measured in best case in millivolts). But with a phase conductor, this will not work. Touching it can result in electrical shock, even fatal. This wire is always energized, current flows to it from generators and transformers and stations. You must always remember that in no case should you touch the working conductor, since a voltage of even a hundred volts can be fatal. And in the socket is two hundred and twenty.

How to determine zero and phase in this case? In the socket, designed according to European standards, there are three conductors at once. The first is phase, which is energized and painted in the most different colors(with the exception of blue shades). The second is zero, which is absolutely safe to touch and is painted in. But the third wire is called zero protective. It is usually colored yellow or green. It is located in sockets on the left, in switches - from below. The phase wire is on the right and top, respectively. Given such colors and features, it is easy to determine where the phase is, and where is zero, and where is the protective neutral wire. But what is it for?

Why do I need a protective conductor in euro sockets?

If the phase is designed to supply current to the outlet, zero - to lead to the source, then why do European standards regulate another wire? If the equipment that is connected is working properly, and all wiring is in working order, then the protective zero will not take part, it is inactive. But if suddenly somewhere there is either an overvoltage or a short circuit on some parts of the devices, then the current enters places that are usually without its influence, that is, not connected either to the phase or to zero. A person can simply feel an electric shock on himself. In the worst situation, you can even die from this, as the heart muscle can stop. This is where the protective neutral wire is needed. It "takes" the short circuit current and directs it to the ground or to the source. Such subtleties depend on the design of the wiring and the characteristics of the room. Therefore, you can safely touch the equipment - there will be no electric shock. The thing is that current always flows along the path of least resistance. In the human body, the value of this parameter is more than one kiloOhm. In a protective conductor, the resistance does not exceed a few tenths of one ohm.

Determining the purpose of conductors

How to determine zero and phase? Everyone has come across these concepts in one way or another. Especially when you need to fix the outlet or do the wiring. Therefore, it is necessary to understand exactly where which conductor is. But how to determine zero and phase? It must be remembered that all manipulations of this kind with electricity are dangerous. Therefore, in case of uncertainty in their actions, it is better to consult a specialist. If you already approach the outlet and the wires in it, then you must first completely de-energize the entire apartment. At a minimum, it can save health and life. As mentioned earlier, usually the designation of phase and zero is done using coloring. With proper labeling, it will not be difficult to distinguish them. Black (or brown) - the color of the phase wire, zero usually has a bluish or bluish tint. If a European standard socket is installed, then the third (protective zero) is green or yellow. What if the wiring is one-color? As a rule, in this case, at the ends of the wires there are usually special insulating tubes that have the necessary color marking. They are called "cambric".

Determining conductors with a special screwdriver

How to determine zero and phase? To do this, it is most convenient to buy a special indicator screwdriver. The handle of such a device is made of translucent or transparent plastic. Inside there is a built-in diode - a luminous light bulb. Top part This screwdriver has a metal one. How to determine zero and phase by this method?

The procedure for performing work when measuring with an indicator screwdriver:

de-energize the apartment;
we clean slightly the ends of the wires;
we separate them to the sides in order not to accidentally cause a short circuit by contacting the phase and zero;
turn on the switch and supply current to the apartment;
we take a screwdriver by the handle, which has a dielectric coating;
put your finger (thumb or index) on the contact, which is located on the back of the outlet;
touch the working end of the indicator to one bare conductor;
carefully observe the reaction of the screwdriver;
if the diode caught fire, then we can state with confidence that;
by elimination, we understand that the remaining conductor is zero.

The indicator screwdriver reacts to the presence of voltage. Naturally, it is not in the neutral wire. However, there is a significant disadvantage of this method. With the help of an indicator screwdriver, it is impossible to understand how to determine: phase, zero, ground - where is what in the case of a European outlet.

Method for determining phase and zero using a voltmeter

If the wires are not painted in the appropriate colors, and there is no indicator screwdriver at hand, then you can go the other way. We need a voltmeter (multimeter, tester). It is necessary to set it to the required range - over two hundred volts of alternating current. How can a tester determine the phase? We take one conductor that departs from the device (indicated by V). We attach it to a previously de-energized conductor (any). Then we apply current (turn on the switch). And just fix what the device display shows. After all of the above, turn off the power again and transfer the tester clamp to another conductor. If there is nothing on the display, then this means that we have either a zero or a grounding protective neutral wire in front of us. However, you can use another method that answers the question: "How to determine zero and phase, as well as grounding." To do this, we de-energize the apartment again, fix the V clamp on one of the wires. We also throw the second on any of the three conductors. The voltage is turned on. If the arrow does not move, then you have chosen zero and protective. Accordingly, the voltage must be turned off again and the position of the V terminal must be changed (throw it onto another previously unused conductor). We turn on the current again and take the appropriate measurements. Then we carry out the same operation, but again we change the conductor. Now we need to check the results. If the first digit turned out to be greater, it means that we measured the voltage between the phase conductor (on which the V terminal hung) and zero. Accordingly, the second wire will be a protective ground. This method is based on measuring the potential difference.

Exotic ways to determine the phase and zero in the wiring

There are also folk methods”, which do not imply the presence of any special devices. They can only be used in the most extreme cases, as they are associated with increased danger to health and life. For example, the potato method. To do this, a freshly cut piece of potato is put on previously de-energized conductors. It is necessary to prevent the wires from touching each other so that there is no short circuit between them. Then, literally for a couple of seconds, voltage is applied and they look at the potatoes. If one section near the wire turns blue, then a phase is connected to it.

The electrician's bible PUE (Electrical Installation Rules) says: electrical wiring along the entire length should make it possible to easily recognize the insulation by its color.

In a home electrical network, as a rule, a three-core conductor is laid, each core has a unique color.

Working zero (N) - blue, sometimes red.
Zero protective conductor (PE) - yellow-green.
Phase (L) - can be white, black, brown.

In some European countries, there are unchanged standards in the colors of the wires by phase. Power for sockets - brown, for lighting - red.

Wiring colors speed up wiring

Colored insulation of conductors significantly speeds up the work of the electrician. AT old days the color of the conductors was either white or black, which in general brought a lot of trouble to the electrician-electrician. When disconnecting, it was necessary to supply power to the conductors in order to determine, with the help of a control, where the phase is and where it is zero. Coloring relieved these torments, everything became very clear.

The only thing that should not be forgotten with an abundance of conductors is to mark i.e. sign their appointment in switchboard, since the conductors can be from several groups to several dozen supply lines.

Phase coloring at electrical substations

The colors in home wiring are not the same as the colors in electrical substations. Three phases A, B, C. Phase A - yellow, phase B - green, phase C - red. They can be present in five-core conductors along with neutral conductors - blue and protective conductor (ground) - yellow-green.

Rules for observing the colors of electrical wiring during installation

From junction box a three-wire or two-wire wire is laid to the switch, depending on whether a one-gang or two-gang switch is installed; the phase breaks, not the neutral conductor. If a white conductor is available, it will be the power conductor. The main thing is to follow the sequence and consistency in colors with other electricians, so that it doesn’t turn out like in Krylov’s fable: “Swan, cancer and pike”.

On sockets, a protective conductor (yellow-green), most often clamped in the middle of the device. We observe polarity, zero worker - on the left, phase - on the right.

At the end I want to mention there are surprises from manufacturers, for example, one conductor is yellow-green, and the other two may be black. Perhaps the manufacturer decided, with a shortage of one color, to use what is. Don't stop production! Crashes and bugs are everywhere. If you get exactly the one where the phase is, and where the zero is up to you, you just need to run around with the control.

At my facilities, they often ask the question: “How, when connecting equipment, to take into account the color of the wires?”

To begin with, I will try to explain why every electrician has his own opinion about color coding. When I studied at the school in 1995-1998, we were taught like this:

Any colored wire is a phase.
White is zero.
Black is the hull or ground.

A few years passed and the black wire was replaced with yellow-green. That is, the following marking has become:

Colored other colors - phase.
Black or white color - neutral wire.

Recently, there has been an introduction of the European standard, which I use.

Yellow-green, green or yellow- ground wire.
Blue color - neutral wire.
The rest (usually white) is the phase.

I hope you understand why there is such a scatter of opinions about wire marking. At what time he studied - he uses such marking. Seven years ago, I used the second marking, and recently switched to the third one, since here, in Minsk, we mainly have to connect imported equipment, and this marking is used everywhere there. In fairness, I recently connected Moscow fans, then the 2nd marking was used there, that is, the plant did not switch to the European standard.

What color to use? Confused? I suggest using the third European. In practice, I usually use the VVG wire, and I have this layout:

Yellow-green color - ground wire.
Blue color - neutral wire.
White color - phase wire

The question arises of what to do if the wire is of non-standard marking. For example, I recently had to lay a wire with a red, blue and black core. I'll tell you how I reasoned:

The blue color is the neutral wire, I think this is understandable.
Black, like white, has no color, and white is a phase, so I made it a phase. Moreover, often in the VVG wire, the white wire comes with a black stripe.
The remaining, red wire, I made the ground.

You may have other reasoning. For example:

Red is dangerous, so the phase.
black as in old times, you can make the earth.
And blue, as in the European standard, you can make zero.

But keep in mind, if you use a wire with a non-standard marking, then be sure to write down the selected marking somewhere. If you don't write it down, it's easy to get confused. Verified by experience.

If you use your marking in your home country, be sure to describe it in a comment indicating your place of residence. Maybe this will help someone.

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 blue color insulation, and yellow-green cambrics were put on the tips 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 or 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 touch can cause severe injury. 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.

In electrical diagrams, the phase is indicated Latin letter L. The same markings are used on wires if color coding 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, during preventive work, it turned out that the marking was outdated, it is 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.