Currently, the industry produces electrical wires different sections with alphanumeric and color markings along the entire length of the wire. Main function any type of marking - visual recognition of each individual wire strand according to its intended purpose, as well as facilitating (accelerating) the installation and operation of wires.
In addition, the separation of cores by color in a power electrical circuit is also one of modern requirements safety precautions regulated by GOST.
Electric wire widely used in production and at home as in power circuits AC(single-phase network 220V or three-phase network 380V), and in circuits DC. Electrical wire can be single-core or stranded. The wire cores can be single-wire or multi-wire.
Single-phase two-wire network 220V
A two-wire electrical network is an electrical network with two electrical conductors. One conductor is phase, the second is neutral. Two-wire electrical systems are still found in older homes today in the form of conventional electrical wiring. Old electrical wiring is a two-wire aluminum wire(“noodles”) with white insulation.
A two-core wire is used to connect switches, ordinary sockets, and lamps.
Because Since both wires of such a wire have the same color, it is quite problematic to visually distinguish phase from zero. Therefore, in order to determine where the phase is and where the zero is, they use an indicator screwdriver, probe, “continuity tester,” tester, multimeter or other electrical measuring device.
Today, in order to distinguish a phase from zero during operation, during installation either a two-core wire with cores of different colors or two single-core wires are used.
Often used as a two-core wire flexible wire with brown and blue (light blue, light blue) vein. It is strongly recommended to use a core as a phase conductor brown, and as neutral conductor- vein blue.
Often there are two-core wires with different colors of cores. For example, in such wires the phase wire may not be brown, but red, black, gray or another color.
In case of using two separate single-core wires There are two labeling options. The first is the use of wires of different colors. For example, you can use a red wire as a phase, and a blue wire as a zero.
If wires of the same color are used, then the phase and neutral wires can be marked either using colored electrical tape, or by using colored heat-shrink tube. When using colored electrical tape, red electrical tape is wound on the phase wire at the beginning and end, and blue electrical tape is wound on the neutral wire.
When using heat shrink, marking single-color wires is almost the same as marking with electrical tape. Red heat shrink is put on the phase wire, and blue heat shrink is put on the neutral wire.
At home, you can mark wire cores with other colors.
Color marking in a single-phase three-wire 220V network
A three-wire electrical network is a network with three electrical conductors. Currently, a three-wire network is becoming more and more common, especially for new wiring.
As in two-wire network one conductor is phase, the second is neutral, but the third conductor is protective wire grounding, which serves to protect against electric shock. A three-wire network uses a three-core wire, usually with a brown, blue and yellow-green core.
The brown wire is a phase, the blue wire is a neutral conductor, the yellow-green wire is a conductor protective grounding. To avoid confusion, it is not recommended to use a yellow-green colored conductor as a phase or neutral conductor.
A three-core wire with colored cores is used to connect modern European-style sockets, which, in addition to the phase and neutral contacts, also have a contact for connecting a grounding conductor. Three-core wires are also used to connect lamps.
Color codes for wires in a three-phase 380V network
A three-phase electrical network can be four-wire or five-wire, i.e. with four or five wire cores. The only difference is the presence or absence of a protective grounding conductor. Those. a four-wire network consists of three phase conductors, a neutral working conductor and the absence of a protective grounding conductor. A five-wire network consists of three phase conductors, a neutral working conductor and the presence of a grounding conductor.
In both four-wire and five-wire networks, a blue conductor is used for the neutral working conductor, and a yellow-green conductor is used for the grounding conductor. Regarding three phases A, B and C, then most often brown, black and gray cores are used for them, respectively. But there are also other colors of wire cores.
A four-core and five-core wire is used to connect a three-phase load or to divide a single-phase load into groups.
DC network
IN electrical network DC usually uses two conductors. The first conductor is positive, and the second conductor is negative. A red wire is used as a positive conductor, and a blue wire is used as a negative conductor.
Based on the results of all of the above, it is worth noting the following: despite certain standard requirements for color marking of wires, without preliminary checking it is not recommended to rely 100% on the color of a particular wire core.
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 is this done and how not to get confused 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 electric shock. To the common man It’s not so easy to deal with, because when you cut the cable, you can see that all the wires have different colors. 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 lived among themselves, as well as when installing 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. 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 single-phase network alternating current is designated by the Latin letter "L" (Line). IN 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). Zero or protective conductor 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 PUE 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! Rigid single-core ground wire 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, it is allowed to install a grounding conductor without a sheath, but if you come across a green-yellow cable with a blue braid and the designation PEN, then you have a grounding combined with a neutral. You should be aware that the ground is never connected to residual current devices located in switchboard. 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 reminder below:
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 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 to use cambrics (heat-shrinkable tubes) to mark all the 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 cores, use an 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.
The individual wires that make up electrical cables have insulation of certain colors. GOST R 50462-2009 regulates the color of insulation; this document describes the features of n and l markings in electrical equipment in order to simplify the work of craftsmen at large facilities and ensure safety during the repair process. Those who decide to independently repair electrical appliances or other similar work should also know what color the ground, phase and neutral wires are.
Features of core colors
To avoid mistakes PUE requirements describe the colors of all major electrical wires. If commissioning works was carried out by an experienced electrician, following the rules PUE and relevant GOSTs, with self-repair you will not need an indicator screwdriver or other devices that determine the purpose of a particular core.
Color marking in electrical equipment according to GOST
Grounding
The yellow-green wire is grounding. IN circuit diagrams Grounding conductors are marked with the letters PE. In some older houses there are PEN wires in which the grounding is combined with the neutral conductor. If the cable was pulled according to the rules, wires with blue insulation were chosen, and only the ends and places of twists were yellow-green (thermal tubes were put on them). The thickness of the “zero” and grounding may be different. Often the thickness of these two conductors is less than the thickness of the phase conductor; this occurs when connecting portable devices.
If we're talking about about laying electrical wiring in multi-storey buildings and in industrial premises, the norms of PUE and GOST 18714-81 come into force, requiring the mandatory installation of protective grounding. Grounding must have minimal resistance to compensate for the consequences of faults on the line and prevent harm to human health. That is, compliance with the standards for color marking of PUE wires is of paramount importance.
"Zero"
What color is the neutral wire? Electrical standards specify that its insulation may be blue, blue with a white stripe, or light blue. Such markings will be present in a cable with any number of cores. In circuit diagrams, “zero” is marked with the letter N; the circuit is closed to it. Sometimes it is called “minus”, and the phase one is called “plus”.
"Phase"
The color of the phase is what is of paramount importance for an electrician: handling conductive conductors requires care and knowledge. The slightest touch of the phase can lead to injury. There are many colors for phase wires marked in the form of the letter L in electrical wiring; the ban only applies to the use of blue, yellow and green colors. If the cable is three-phase, the serial number of the core is added to the letter L.
When a single-phase circuit is separated from a three-phase one, electricians use cables with strictly the same colors, monitoring the color of the phase and zero in the wire. Before starting work, they determine for themselves how the different wires will be connected, and then follow the chosen color. Sometimes thermal casings are fused onto them or several turns of colored appropriate electrical tape are wound.
According to GOST:
- black phase wires are used in power circuits operating with direct and alternating current;
- red color - used in control circuits designed for alternating current;
- With orange- found in interlock control circuits powered from external sources.
How to determine the purpose of a wire - neutral or ground?
L N marking in electrical engineering is not always observed in old buildings, so the question arises of independently distinguishing between the neutral wire and the ground wire. When the circuit is closed, the “zero” passes electric current. The grounding wire has only a protective function, and in “normal” mode no current flows through it.
You can find out whether it is “zero” or “ground” like this:
- Use an ohmmeter, having first turned off the voltage between the measurement points. The resistance on the ground wire will not exceed 4 ohms.
- Use a voltmeter and sequentially measure the voltage between the “phase” and other wires (the method is suitable for three-core cables). The ground wire will give the greatest value.
- If the colors of the “phase”, “zero” and “ground” wires are unknown, and you need to find out the voltage between the ground wire and some known grounded object (for example, a heating radiator), a voltmeter is also useful. True, when connecting the “earth” and a grounded object, it will not show anything. But a small voltage will be reflected in its indicator if you do the same with the “zero” wire.
In a two-core cable there will always be only a phase and neutral wire.
What to do if all the wires in the cable have the same color insulation
The question of marking wires by color does not make sense when you have to work with single-color wires - for example, when repairing wiring in old houses. For such cases, there are kits that make it possible to mark the cores. Areas for fastening marking devices are prescribed by GOST requirements; they are usually fixed next to the point of connection to the bus.
How to mark a wire with two cores
If all the wires in the cable have the same insulation, and the electrical appliance is already connected to the network, the craftsmen use indicator screwdrivers. The latter glow when metal part concerns phase wire. To mark a two-core cable, in addition to such a screwdriver, you will need thermal casings or multi-colored electrical tape. Colors will be marked only at the joints - it is not necessary to wrap the core with colored tubes or electrical tape along its entire length.
Probe screwdriver-indicator
Phase wires can be marked with any colors except blue, yellow and green. If a two-core cable is connected to a single-phase network, it is customary to secretly mark the phase wire in red.
How to mark a wire with three cores
What color is the ground wire in a three-wire wire? If the answer to the question cannot be determined immediately, all the insulation on the wires is the same color, a multimeter will help out. The device is set to alternating current, and the master sequentially touches with both probes first the phase wire, then the remaining wires, memorizing the indicators. Touching phase and zero will produce a higher voltage than touching phase and ground.
What color is the ground wire? It has a yellow-green color. It is this kind of thermal casing or electrical tape that should be used to mark the “ground” in a three-core cable. On the “zero” you should wind a blue tape, on the phase - not blue or yellow-green thermal cambric.
Letter designation of phase, zero and ground
Usage different colors wires in electrical wiring is a convenient and logical measure that simplifies repair and installation work. If wires with multi-colored conductors are laid in the house, during repairs you will not have to waste time “ringing” each of them, and, for example, a broken phase conductor will be detected quickly. The presence of phase and zero also matters, but working with letters and numbers still takes longer than with color: just look at the cable and the purpose of the cores immediately becomes clear.
Installation is unthinkable today electric cable without the use of colored wires. Such marking of conductors is an urgent need, since, by indicating the purpose of each wire, it helps to reduce the likelihood of errors during installation and, as a result, a short circuit.
Before you understand the decoding of the markings, it is recommended that you familiarize yourself with the parameters by which the wires are divided:
- Number of cores. Depending on this parameter, the cable can be used to ensure the operation of electric motors, for wiring in a house or apartment, for transmitting current in power networks.
- Current-carrying conductor material. As a material in electrical applications the most commonly used are copper and aluminum or a combination of these metals.
- Insulation. Wires can be with or without insulation. Bare conductors provide communication for power lines. Insulated ones are laid in places where there is a possibility of exposure to them external factors in the form of wind, water, dust or snow. Plastic, rubber, lead, paper and many other materials are used as insulation.
- Cable cross-section. Using this indicator you can determine the strength of alternating or direct current, which will pass through the conductors.
- Other indicators. Resistance, power and voltage indicators are very important for network wiring and connecting various devices.
Knowing which conductors are responsible for the loads, you can correctly connect to the meter, repair the wiring, connect the oxygen sensor in the car, etc.
Marking of wires for alternating three-phase current
By looking at the color markings, you can easily determine ground, zero and phase. In modern electrical conductors each core has an individual color. Knowing which core corresponds to which color, you can easily perform installation. If the installation was carried out with new wiring and by modern standards and rules, then this is quite enough.
- The neutral or working zero is blue or blue-white.
- Grounding or protective zero is a yellow-green wire.
- The phase can be marked with all other colors, including:
- turquoise;
- orange;
- white;
- pink;
- violet;
- grey;
- red;
- brown;
- black.
Once you understand the color of the marking, you can easily determine which wire is responsible for which function. Due to a different operating scheme, an exception may be conductors suitable for switches, switches, etc.
Color of wires plus (+) and minus (-) in DC networks
In some areas in national economy DC networks are used:
- for operational protection circuits and automation power supply at electrical substations;
- in electrified transport;
- in construction, industry, when storing materials.
In such networks, only two conductors are used: positive and negative buses. There is no phase or neutral conductor in them.
Marking of wires and buses for DC networks:
- red color is used for positive charge wires;
- blue – for tires and wires with a negative charge;
- Blue color indicates the middle conductor.
If the DC network is created from a three-wire network (by branching), then the color of the positive conductor is the same as the positive conductor of the three-wire circuit.
Wire colors in electrical wiring
Identification of wires by color is very convenient, especially when their installation and connection is done by one person, and another person will maintain and repair them.
Every the color of the electrical conductor determines its purpose in the cable according to a certain standard, which has been changed several times since the times of the USSR.
Today, conductors in AC electrical installations with a solidly grounded neutral and voltages up to a thousand volts have very specific markings.
Color of zero working and zero protective wires
- Neutral working conductors are indicated in blue.
- Zero protective ones are painted in yellow-green transverse or longitudinal stripes.
- Combined neutral protective and neutral working conductor along its entire length marked in blue with yellow-green stripes at the junction points. It can also be the other way around - the entire conductor is yellow-green, and the connection points are painted blue.
This color combination is used only for marking neutral protective pinch conductors.
How to independently determine the ground, zero and phase of wires if there are no markings?
Quite often situations arise when the connection is made in an unclear way. Some electricians even today may use outdated wiring standards, which is why other specialists have to look for zero and phase using a probe and mark conductors in the right color electrical tape or heat shrink tubing of the desired color.
Determining the phase using an indicator screwdriver
Inside the probe there is a resistor and a lamp. When the tip of the screwdriver touches the contact and the live conductor, the circuit closes and the lamp lights up. Resistance reduces the current to a minimum, protecting against electrical shock. Thus, it is quite easy to find out which wire is phase.
This is the most preferable option for determining the phase, especially since the cost of the screwdriver is quite affordable. Its main drawback is the possibility of false positives. Sometimes the indicator screwdriver can react to interference and determine the presence of voltage where there is none.
Determination of ground, zero and phase using a test lamp
This method of determination is quite effective, but requires special caution:
- a lamp is screwed into the socket, and wires with the insulation removed at the ends are fixed into its terminals;
- you can also use ordinary table lamp with electrical plug;
- the technology is quite simple - the lamp wires are alternately connected to the conductors that require definition.
In this way, you can only find out which conductor has a phase. If the control lamp lights up, then this wire has a phase. If the lamp does not light, then there is no phase or zero among the wires. This also cannot be ruled out.
To determine the phase wire, you can connect one of the ends coming from the lamp to a known zero, and then when the second end is connected to the phase conductor, the lamp will light up. The wire that remains will be zero accordingly.
The method of determining phase or zero using a lamp is good for checking the functionality of the wiring.
Please remember that when working with electrical wires care and caution are required.
Today it is difficult to imagine electrical wiring without the use of colored insulation. And these are not marketing “tricks” of manufacturers seeking to present their goods in colors, and unfashionable innovations that consumers strive for. In fact, this is a simple and practical necessity, which is determined by strict state standards for compliance with correct labeling. What is this for?
Wire colors in electrical connections
Color marking
All the variety of colors and certain colors, selected from this palette, are reduced to one (single) standard (PUE). Thus, wire cores are identified by color or letter and number designations. The adoption of a unified standard for the color identification of electrical wires has greatly facilitated the work associated with their switching. Each core has a specific purpose and is indicated by a corresponding tone (blue, yellow, green, gray, etc.).
Wires are marked by color along their entire length. Additionally, identification is carried out at connection points and at the ends of the cores. To do this, use colored electrical tape or heat-shrinkable tubes (cambrics) of appropriate colors.
Let's look at how electrical wiring is done and wire color coding for three-phase, single-phase and DC networks.
Color marking of wires and buses of three-phase alternating current
Painting of busbars and high-voltage transformer bushings in three-phase networks done as follows:
- tires with phase “A” are painted yellow;
- buses with phase “B” - green;
- buses with phase “C” - red.
Marking of wires by color. Electrical wire colors (DC buses)
In the national economy, direct current circuits are often used. They find their application in certain areas:
In DC networks there is no phase and neutral contact. For such networks, only two contacts of different polarities are used - plus and minus. To distinguish them, two colors are respectively used. A positive charge turns red and a negative charge turns blue. Blue denote the middle contact, which is marked with the letter “M”.
“Old-timers” of electrical installation are probably familiar with the old methods of wiring and color marking of electrical wires. The main colors of the electric cable were white and black. But that time is a thing of the past. Each color now, and there are clearly more than two, has its own purpose and dominant profile.
Contact colors in electrics indicate the purpose and belonging of conductors to a specific group, which facilitates their switching. The possibility of an error during the installation process, which could lead to short circuit during test connection or electric shock during repair is significantly reduced.
Marking of wires by color. Color palette of protective zero and working contacts
Zero working contact is indicated blue tone and the letter N. The PE marking denotes the zero protective contact, which is painted in yellow-green stripes. A combination of such tones is used when marking pinch conductors.
A blue conductor along its entire length with yellow-green stripes at the connection points indicates a combined zero working and zero protective connection (PEN). However, GOST also allows for the opposite of this color:
- Working zero contact is designated by the letter N and is blue in color.
- Protective zero(PE) with a yellow-green color.
- Combined(PEN) are identified by their yellow-green color and blue markings at the ends.
Single-phase electrical circuit. Coloring of phase wires
According to PUE standards, phase contacts are usually designated in black, red, purple, white, orange or turquoise.
Single-phase electrical circuits are created by branching off a three-phase electrical network. In this case, the color of the phase contact of a single-phase circuit must match the color of the phase wire of a three-phase connection. In this case, the color marking of the phase contacts should not coincide with the N - PE - PEN colors. On unmarked cables, colored marks are placed at the connection point. To mark them use colored electrical tape or heat shrink tube(cambric).
What color is the ground wire? Marking of wires by color (phase - zero - ground)
When installing lighting networks and power supply to sockets, use a cable with three wires (three-core cable). The use of a standard color system (phase-neutral-ground wire color) significantly reduces repair time. Multi-core wiring in standard multi-colored insulation greatly simplifies installation electrical circuits and installation work on wiring AC networks with its grounding. This is especially true when wiring and repairing the electrical system, which is done by different masters, but under general management GOST. Otherwise, each master would have to once again double-check the work of his predecessor.
“Earth” is usually indicated by the color yellow-green and marked PE. Sometimes there is a green-yellow color and the marking “P E N”. In this case, there is a blue braid at the ends of the electrical wire at the attachment points and the grounding is combined with the neutral.
The distribution panel is connected to the grounding bus and to the metal door of the panel. Junction box usually connected to the grounded wires of lamps or the grounding contacts of sockets.
Marking of wires by color. Designation of zero and neutral
“Zero” is indicated in blue. In the distribution panel it is connected to the zero bus and is designated by the letter N. All blue wires are also connected to the bus. It is connected to the output using a meter or directly, without installing an automatic device.
The distribution box wires (with the exception of the wire from the switch) are indicated by a blue neutral palette. When connected, they do not take part in the switching process. Blue “zero” wires are connected to sockets and contact N, which is indicated on back side sockets
Marking of wires by color. Phase color designation
The phase wire is usually indicated in red or black. Although its colors may not be so clear. It can also be brown, but never blue, green or yellow. In automatic switchboards, the “phase” coming from the consumer’s load is connected to the lower contact of the meter. Switching of the phase wire is carried out in switches. In this case, the contact closes during shutdown and voltage is supplied to consumers. The black wire of the phase socket is connected to the contact, which is designated by the letter L.
Alphanumeric designation of wires by color
Knowledge of the basic color markings of wires and their purpose will help any amateur electrician in installing home electrical wiring (with grounding). If you wish, you can easily make it according to the required standards in compliance with all technical standards.