Color marking of wires is far from being an advertising feature of manufacturers, as some novice electricians believe. This is a special designation that allows the electrician to determine zero, grounding and phase without the use of additional measuring instruments.
If the contacts are connected incorrectly, unpleasant consequences may occur in the form of a short circuit and electric shock to a person.
The main purpose of applying color marking is to reduce the time required to connect contacts and create safe conditions when carrying out electrical installation work. Currently, in accordance with the PUE and European standards, each core has its own clearly defined color.
We will talk about what color the neutral wire, grounding and phase have.
Ground wire
According to standards, ground insulation is colored yellow-green. Some manufacturers apply yellow-green stripes in the longitudinal and transverse directions to the grounding conductor. Rarely, but still found, the shells are purely green or purely yellow.
On electrical diagrams, “ground” is designated by two Latin letters “PE”. Grounding is often called zero protection, but it is not a working zero and should not be confused.
Neutral wire
Both in a single-phase and three-phase electrical network, the neutral is painted blue or blue. On the electrical diagram, zero is indicated by the Latin letter “N”. Neutral is also called zero or neutral working contact.
Phase wire
Depending on the manufacturer, this wire is marked with the following colors:
- white;
- turquoise;
- black;
- brown;
- pink;
- red;
- violet;
- orange.
The most common colors to indicate phase are black, white and brown.
Despite its apparent simplicity, color marking has a number of features that raise the following questions for beginners:
1.What is PEN?
2. How to determine phase, grounding and zero if the insulation has a non-standard color or is completely colorless?
Let's look at each point.
What is PEN?
The TN-C type grounding system, which is outdated today, involves combining grounding and neutral. Its main advantage is the speed of electrical installation work. The disadvantage of TN-C is the high probability of electric shock damage when installing wiring in an apartment or house.
The main color to indicate the combined wire is yellow-green, but at the ends of the insulation there is a blue color characteristic of the neutral wire.
On the electrical diagram, such a contact is designated by three Latin letters “PEN”.
How to find phase, ground and zero?
There are times when, when repairing a household electrical network, it turns out that all the conductors are the same color. In this case, how can you determine which wire is which?
In a single-phase network, where there are only two wires, without grounding, you just need to have a special indicator screwdriver with you. First you need to turn off the electricity at the distribution panel. Then the wires are stripped and routed to the sides. Now turn on the electricity again and bring the indicator to each of the wires one by one. If the light on the screwdriver lights up upon contact, it means it is a phase, and the second wire is, therefore, zero.
If the electrical network is three-phase, then you will need more complex equipment - a multimeter with measuring probes. First, set the device to a value above 220 Volts. We fix one probe on the phase, and with the second we determine grounding and zero. When contacting zero, the tester should show a voltage of 220 Volts. The ground wire will show a slightly lower voltage.
If you don’t have an indicator screwdriver or a multitester at hand, you can determine the identity of the wire by looking at the insulation. The important thing to know here is that the blue shell is always neutral. Even with the most non-standard markings, its color does not change. The other two wires are more difficult to install.
The first method is based on associations. For example, in front of you is a colored and white or black contact. Typically, land is designated white or black. Therefore, the remaining wire is a phase.
Second way. We discard the neutral again. All that's left is red and black. According to the PUE, white insulation is a phase. Then the red conductor is the ground.
In circuits with direct current, the color markings of minus and plus are represented by black and red insulation colors, respectively. In a three-phase transformer network, each phase is painted in an individual color:
- A-yellow;
- B-green;
- C-red.
Zero, as always, is blue, and ground is yellow-green. In cables designed for a voltage of 380 Volts, the wires are designated as follows:
- A-white;
- B-black;
- C-red.
The protective and neutral conductors do not differ in markings from the previous version.
We designate the wires ourselves
If there is no visual marking, after repair work you must independently indicate the identity of the wires. Brightly colored insulating tape or heat shrink tubing is suitable for this purpose.
According to GOST, marking of cores must be carried out at the ends of the conductors - at the points of their contact with the bus.
Such notes will greatly facilitate future repairs and maintenance.
If you incorrectly connect the contacts to each other by color, this can cause such adverse consequences as electric shock to a person.
The main purpose of color marking is to create safe conditions for electrical installation work, as well as reduce the time for searching and connecting contacts. Today, according to the PUE and existing European standards, each core has its own insulation color. We will talk further about what color the wire is phase, neutral, ground!
What does grounding look like?
According to the PUE, the ground insulation should be painted yellow-green. Please note that the manufacturer also applies yellow-green stripes to the ground wire in the transverse and longitudinal direction. In some cases, the shell may be pure yellow or pure green. On an electrical diagram, grounding is usually denoted by the Latin letters “PE”. Very often, “ground” is called zero protection; it should not be confused with working zero (zero)!
Appearance Graphic representation on the diagram
What does neutral look like?
In three-phase and single-phase electrical networks, the color of the zero should be blue or light blue. On the electrical diagram, “0” is usually denoted by the Latin letter “N”. Zero is also called neutral or zero working contact!
Standard color Indication of neutral on the electrical diagram
What does the phase look like?
The phase wire (L) can be marked by the manufacturer in one of the following colors:
- black;
- white;
- grey;
- red;
- brown;
- orange;
- violet;
- pink;
- turquoise.
The most common colors of the phase wire are brown, black and white.
Shell color Electrical diagram
Important to know!
Color marking of wires in electrical engineering has many features and beginners often face questions such as:
- “What is the abbreviation PEN?”;
- “How to find grounding, phase, zero if the insulation is colorless or has a non-standard color?”;
- “How to independently indicate phase, grounding, zero?”;
- “What other standards exist for insulation color?”
We will now briefly give a simple explanation to all these questions!
What is PEN?
The currently outdated TN-C grounding system involves the use of a combination of neutral and ground. The advantage of such a system is the ease of electrical installation work. Disadvantage - the threat of electric shock in any apartment.
The color of the combined wire is yellow-green (like PE), but at the ends the insulation has a blue color, characteristic of neutral. On the electrical diagram, the combined contact is indicated by three Latin letters - “PEN”.
Indication "PEN" on the electrical diagram
How to find L, N, PE?
So, you are faced with the following situation: during the repair of a household electrical network, it turned out that all the conductors are the same color. In this case, how do you find out which wire means what?
If the single-phase network is presented without “ground” (2 wires), then all you need is a special indicator screwdriver. With its help, you can easily determine where 0 is and where the phase is. We talked about that. First, turn off the electricity supply on the panel. Next, we strip the two conductors and separate them apart from each other. After this, turn on the electricity supply and carefully use the indicator to determine phase/zero. If the light bulb lights up upon contact with the core, this is a phase, respectively, the second core is zero.
If the electrical wiring has a ground wire, it is necessary to use equipment such as a multimeter. This device has two tentacles. First you need to set the AC current measurement range to above 220 Volts. Next, we fix one tentacle on the phase contact, and with the help of the second tentacle we determine zero/grounding. When you touch 0, the multimeter will display a voltage value within 220 Volts. If you touch the “ground”, the voltage will definitely be a little lower. A more intelligible one was provided in the corresponding article, which we recommend that you read!
There is another method of determination. If you don’t have a multimeter and an indicator screwdriver at hand, you can try to determine what color the L and N wires are by their insulation. In this case, you must remember that the blue shell is always ZERO. In any non-standard marking, the color of the zero does not change. The other two wires will be a little more difficult to identify.
The first version of associations. You see the remaining colored and black or white contact. In the good old days, the ground was marked with black or white insulation. It is quite reasonable to assume that this is it, the remaining color is phase (L).
Second option. Zero, again, is immediately removed, leaving a red and black/white wire. If the insulation is white, then according to the PUE it is a phase. This means that the remaining red is earth.
Please note that this method is extremely dangerous. If you decide to use it, be sure to make notes for yourself so that you don’t get an electric shock while plugging in!
I would also like to note a very important nuance - in a DC circuit The color marking of plus and minus is represented by black (-) and red (+) insulation. As for a three-phase network (for example, on transformers), all three phases have their own individual color: phase A - yellow, B - green, C - red. Zero, as usual, is blue, and ground is yellow-green. In a 380V cable, wire A is white, B is black, C is red. The neutral working and protective conductors do not differ from the previous version of the color marking.
How can I specify L, N, PE myself?
In the event that the visual designation is missing or differs from the standard one, it is recommended that you independently indicate all the elements after the repair work. To do this, you can use colored electrical tape or a special product - heat-shrinkable tube, also called cambric. According to the requirements of the PUE, GOST and generally accepted recommendations, the indication of cores must be carried out at the ends of the conductor - at the points of its connection to the bus (as shown in the photo).
Small notes by color will make repairs and maintenance easier for both you and the electrician who may be repairing the home electrical network after you! We talked about this in a separate article.
Existing factory standards
Insulation designations change slightly every decade, so perhaps this information will be useful to you.
Until 2000, the following color markings for wires were used:
- white – N;
- black – PE;
- bright - L.
A few years after this standard, a significant change was made: PE was “repainted” yellow-green (as it is now).
Thus, the products began to look like this:
- yellow-green wire – ground;
- black (and sometimes white) – neutral (N);
- bright – phase.
Color solutions
If for some reason you are confused between the contacts, we provide for your attention a detailed breakdown of the markings of wires and cables by color, which today corresponds to European and domestic standards:
In modern life, marking wires by color is not an advertising ploy by the manufacturer to stand out from others. This is a necessity and requirement, without which fast and high-quality installation of electrical wiring is impossible. How does this color help?
- quick identification of wire purpose (phase, neutral or ground)
- reducing the number of erroneous connections during the installation process
- no need to test the wire for phasing
Manufacturers choose conductor colors not according to their own wishes, but according to the rules. Moreover, not only a color, but also a numerical and alphabetic designation can be applied to the conductor. 
The color is applied along the entire length of the core insulation. But in some areas you can also use multi-colored cambrics for heat shrink. They are mainly widely used in cable terminations. 
Colors for 220V and 380V single-phase and three-phase voltage
In a three-phase network, wires and buses were previously colored as follows:
Yellow color
Green color
Red color
To make it easier to remember the order of colors, electricians used the abbreviation ZH-Z-K. 
From 01/01/2011, new standards were introduced in accordance with GOST R 50462-2009 ():
Brown
Now it's time to switch to abbreviations - K-H-S! Subjectively speaking, this marking is inferior in clarity to the previous color scheme Zh-Z-K. 
Imagine that there is poor lighting in the control room or room, dust on the wires? Which do you think your eye is better at distinguishing between yellow and green or brown and black? The rules in this case stipulate the need for letter designation and marking of the cores, in addition to color.
Letter designation of wires
What should be the letter designation of wires according to GOST is presented in the following tables: 
It is best to apply these letters using special tag rings. 
They are a PVC tube, pre-cut, with letters and numbers printed on it. 
According to the new rules, marking phase conductors yellow or green is prohibited. Precisely because of their similarity with the yellow-green grounding conductor.
It is also worth noting that the brown color is precisely phase A or L1 (simply L in a single-phase 220V network), and black is phase B or L2. When you conduct wiring for yourself, you may unwittingly miss this moment. But if the electrical work is being done for an industrial facility, then you will be required to strictly adhere to the international standard and correct phasing.
White color is the cheapest option when making core insulation, as it does not require the use of dyes. Therefore, it is most often used by manufacturers of cheap cable brands. There are no special labeling guidelines for this color.
Coloring in a DC network
DC networks use 3 buses. The usual zero and phase are missing here. There is a positive conductor or bus (with a plus sign) and a negative conductor (with a minus sign). According to the old rules, the positive tire should be red, the negative tire should be blue. Zero operating bus - blue. 
According to new standards from 01/01/2011:
Plus
Brown color
Minus
Gray color
Middle conductor
Blue color
Errors and color options for phase, neutral and ground wires
The issue of marking wires by color becomes acute when the wiring is installed by one electrician and then serviced by another. If all color rules are followed, both time and money are saved significantly on troubleshooting.
Unfortunately, in old Soviet wiring, most of the conductors are single-colored and there is no way to do this without a probe or multimeter. 
If color marking exists and is observed, then the neutral and protective wires should be:
Neutral wire N should be blue.
Zero protective PE – yellow-green.
The conductor combining the protective zero and the working zero PEN is yellow-green along the entire length of the wire, but at the end at the junction it is blue. 
When coloring phase wires, the manufacturer is given a choice from a variety of color options. Here are the main ones: 
Non-standard wire color options
Sometimes, due to incorrect labeling of colors by manufacturers, GOST standards have to be ignored. For example, you have 3 wires in a cable of different colors:
- blue
- brown
- black
In this case, you do the phase according to the rules, namely in brown. The neutral wire will be blue. But the black core will become grounding. In this version, the colors will at least resemble the Soviet standard. 
Another of the “inconvenient” options for combining colors of cable cores:
- black
- blue
- red
To violate GOST as little as possible and be close to its requirements, make the phase black. Blue is zero, but red will be the protective conductor PE.
Just be sure to mark it at the end with yellow and green electrical tape.
But what to do if the cable does not have a single color that resembles a phase wire? That is, the colors black, brown and gray are missing. Then choose for the phase the wire that corresponds as closely as possible to the brown color established by the rules. For example, red.
At the ends of the wires, according to the phasing, you can put on multi-colored insulating thermal tubes or multi-colored electrical tape. 
To avoid resorting to such methods, at the stage of purchasing and selecting a cable, pay attention to its color in advance.
What to do if the cable has already been laid without observing color markings?
Most often, you may encounter a situation where the wiring has already been laid, and the electrician who did it, as a rule, did not bother to familiarize himself with the rules of color marking and GOST. What to do in this case?
There is nothing left to do but pick up the instruments - a probe, an indicator, a dialer, and spend time looking for the necessary conductors. 
After each definition of a particular conductor, use colored cambrics to designate them according to GOST and move on to the next one. It is enough to make this designation only at the end and beginning of the cable, and not along its entire length.
It is easy to distinguish phase conductors from neutral conductors. How to distinguish a zero worker from a protective one can be found in the article "".
Tips related to wire colors that should be followed during installation:
- Try not to use cables from different manufacturers. As a rule, their colors are not the same, which can lead to installation errors in the future.
- if you still have to work with cables of different manufacturers and colors, at the very beginning, ring all the cores and mark them in advance with multi-colored electrical tape so as not to confuse them in the future. Don't rely on your memory
- when you have to extend a short cable, use wires of the same colors as in the main section.
- try not to use cables that do not have yellow-green colored cores (protective zero)
- If the cable does not have a yellow-green core, then use the closest related color as the ground.
In most modern cables, the conductors have insulation of different colors. These colors have a certain meaning and are chosen for a reason. What is color marking of wires and how to use it to determine where the zero and ground are, and where the phase is, and we will talk further.
In electrical engineering, it is customary to distinguish wires by color. This makes the work much easier and faster: you see a set of wires of different colors and, based on the color, you can guess which one is intended for what. But, if the wiring is not factory-made and you did not do it, before starting work you should definitely check whether the colors correspond to the intended purpose.
To do this, 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 “along the way.” So knowing the color coding of wires is one of the essential skills of a home craftsman.
Ground wire color coding
According to the latest rules, wiring in a house or apartment must be grounded. In recent years, all household and construction equipment have been produced with a grounding wire. Moreover, the factory warranty is maintained only if the power supply is supplied with a working grounding.
To avoid confusion, it is customary to use a yellow-green color for the ground wire. The hard solid wire has a green base color with a yellow stripe, while the soft stranded wire has a yellow base color with a green longitudinal stripe. Occasionally there may be specimens with horizontal stripes or just green, but this is not standard.
Ground wire color - single-core and stranded
Sometimes the cable only has a bright green or yellow wire. In this case, they are used as “earthen”. On diagrams, “ground” 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, in 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”. The color blue is allocated for it (bright blue or dark blue, occasionally blue). On color diagrams, this circuit is also drawn in blue and signed with the Latin letter N. The contacts to which the neutral must be connected are also labeled.
Neutral color - blue or light blue
Cables with flexible stranded conductors tend to use lighter shades, while solid solid conductors have a sheath of darker, richer tones.
Coloring phase
With phase conductors it is somewhat more complicated. They are painted in different colors. Already used ones are excluded - green, yellow and blue - and all others can be present. When working with these wires, you need to be especially careful and attentive, because they are the ones where voltage is present.
Color marking of wires: what color is the phase - possible options
So, the most common color markings for phase wires are red, white and black. There may also be brown, turquoise orange, pink, purple, gray.
On diagrams and terminals, phase wires are signed with the Latin letter L; in multiphase networks, the phase number is next to it (L1, L2, L3). On cables with several phases, they have different colors. This makes wiring easier.
How to determine if the wires are connected correctly
When trying to install an additional socket, connect a chandelier, or household appliances, you need to know which wire is phase, which is neutral, and which is ground. If the connection is incorrect, the equipment will fail, and careless touching of live wires can end sadly.
You need to make sure that the colors of the wires - ground, phase, zero - match their wiring
The easiest way to navigate is by color coding of the wires. But things are not always simple. Firstly, in old houses the wiring is usually monochromatic - two or three white or black wires stick out. In this case, you need to understand it specifically, and then hang tags or leave colored marks. Secondly, even if the conductors in the cable are painted 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, first we 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; to determine zero and neutral, you will need a tester or multimeter.
Checking with indicator
Indicator screwdrivers come in several types. There are models on which the LED lights up when a metal part touches live parts. In other models, checking requires an additional button press. In any case, when voltage is present, the LED lights up.
Using an indicator screwdriver you can find the phases. We touch the exposed conductor with the metal part (press the button if necessary) and see if the LED lights up. Lit - this is a phase. Does not light - neutral or ground.
We work carefully, with one hand. Second, we don’t touch walls or metal objects (pipes, for example). If the wires in the cable you are testing are long and flexible, you can hold the insulation with your other hand (stay away from bare ends).
Checking with a multimeter or tester
We set the scale on the device, which is slightly higher than the expected voltage in the network, and connect the probes. If we are calling a household single-phase 220V network, set the switch to the 250V position. With one probe we touch the exposed part of the phase wire, with the second we touch the supposed neutral (blue). If at the same time the arrow on the device deviates (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 is identified by color as “ground”. 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 go through all the pairs, determining the purpose of the conductors according to the indications. We use the same rule: when testing a phase-ground pair, the readings are lower than when testing a phase-zero pair.
Those who have dealt with electrical wires at least once in their lives could not help but notice that the cables always have different insulation colors. It was not invented for beauty and bright colors. It is thanks to the color scheme in clothes that wires are easier to recognize phases, grounding and neutral wires. All of them have their own coloring, which makes working with electrical wiring many times more convenient and safe. The most important thing for the master is to know which wire should be marked with which color.
Wire color coding
When working with electrical wiring, the greatest danger is represented by the wires to which the phase is connected. Contact with the phase can be fatal, so the brightest warning colors, for example red, were selected for these electrical wires.
In addition, if the wires are marked with different colors, then when repairing a particular part, you can quickly determine which of the wire bundles need to be checked first, and which of them are the most dangerous.
Most often, the following colors are used for phase wires:
- Red;
- Black;
- Brown;
- Orange;
- Lilac,
- Pink;
- Violet;
- White;
- Gray.
It is these colors that phase wires can be painted. You can deal with them easier if you exclude the neutral wire and ground. For convenience, in the diagram the image of a phase wire is usually denoted by the Latin letter L. If there is not one phase, but several, a numerical designation should be added to the letter, which looks like this: L1, L2 and L3, for three-phase in 380 V networks. In some designs, the first phase (mass) may be designated by the letter A, the second by B, and the third by C.
What color is the ground wire?
According to modern standards, the grounding conductor should be yellow-green in color. In appearance it looks like yellow insulation, on which there are two longitudinal bright green stripes. But sometimes there is also a color of transverse green-yellow stripes.
Sometimes, the cable may only have bright green or yellow conductors. In this case, “earth” will be indicated by this color. It will also be displayed in the corresponding colors on the diagrams. Most often, engineers draw bright green wires, but sometimes you can see yellow conductors. On diagrams or devices, “ground” is designated by the Latin (in English) letters PE. Accordingly, the contacts where the “ground” wire needs to be connected are also marked.
Sometimes experts call the grounding wire “neutral and protective,” but this should not be confused. If you see such a designation, then know that this is an earth wire, and it is called protective because it reduces the risk of electric shock.
The zero or neutral wire is marked in the following color:
- Blue;
- Blue;
- Blue with white stripe.
No colors are used in electrical engineering to mark the neutral wire. This is how you will find it in any, be it three-core, five-wire, or maybe with even more conductors. Blue and its shades are usually used to draw “zero” in various diagrams. Professionals call it a working zero because (which cannot be said about grounding) it is involved in electrical wiring with power. Some, when reading the diagram, call it a minus, while everyone considers the phase “plus”.
How to check wire connections by color
Electrical wire colors are designed to make it easier to identify wires. However, relying only on the color is dangerous, because some newbie, or an irresponsible employee from the housing and communal services complex, could connect them incorrectly. In this regard, before starting work, it is necessary to make sure that their marking or connection is correct.
In order to check the wires for polarity, take an indicator screwdriver or a multimeter. It is worth noting that it is much easier to work with a screwdriver: when you touch the phase, the LED built into the housing lights up.
If the cable is two-wire, then there are practically no problems - you have eliminated the phase, which means the second conductor that remains is zero. However, three-core wires are also common. Here you will need a tester or multimeter to determine. With their help, it is also not difficult to determine which wires are phase (positive) and which are neutral.
This is done as follows:
- The switch is set on the device in such a way as to select a jackal of more than 220 V.
- Then you need to take two probes in your hands, and holding them by the plastic handles, very carefully touch the rod of one of the probes to the found phase wire, and lean the second one against the supposed zero.
- After this, the screen should display 220 V, or the voltage that actually exists in the network. Today it may be lower.
If the display shows a value of 220 V or something in this range, then the other wire is zero, and the remaining one is presumably ground. If the value that appears on the display is less, you should continue checking. We again touch the phase with one probe, and the supposed ground with the other. If the instrument readings are lower than in the case of the first measurement, then in front of you is “ground”. According to standards, it should be green or yellow. If suddenly the readings turn out to be higher, this means that you have made a mistake somewhere, and you have a “zero” wire in front of you. The way out of this situation is to either look for exactly where the wires were connected incorrectly, or leave everything as is, remembering that the wires are mixed up.
Wire designations in electrical diagrams: connection features
When starting any electrical installation work on lines where a network has already been laid, you need to make sure that the wires are connected correctly. This is done using special testing devices.
It must be remembered that when checking the phase-zero connection, the readings of the indicator multimeter will always be higher than in the case of continuity of the phase-ground pair.
According to the standards, wires in electrical circuits are color coded. This fact allows the electrician to find zero, grounding and phase in a short period of time. If these wires are connected incorrectly, a short circuit will occur. Sometimes such an oversight results in a person receiving an electric shock. Therefore, you cannot neglect the rules (PUE) of connection, and you need to know that the special color marking of wires is intended to ensure safety when working with electrical wiring. In addition, this systematization significantly reduces the electrician’s work time, since he is able to quickly find the contacts he needs.
Features of working with electrical wires of different colors:
- If you need to install a new one or replace an old outlet, then it is not necessary to determine the phase. The plug doesn’t care at all which side you connect it to.
- In the case when you connect a switch from a chandelier, you need to know that it needs to be supplied with a specific phase, and only zero to the light bulbs.
- If the color of the contacts and phase and zero are exactly the same, then the value of the conductors is determined using an indicator screwdriver, where the handle is made of transparent plastic with a diode inside.
- Before identifying a conductor, the electrical circuit in a house or other room must be de-energized, and the wires at the ends must be cleaned and spread apart. If this is not done, they may accidentally come into contact and result in a short circuit.
The use of color marking in electrical engineering has made people's lives much easier. In addition, thanks to color coding, safety when working with live wires has risen to a high level.
Designations and colors of wires in electrical engineering (video)
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