Rated breaking capacity of ouzo. RCD. Design, principle of operation, switching circuits and characteristics of RCDs. RCD electromechanical or electronic

When opening any electrical wire, every electrician encounters wires of different colors. Why do manufacturers do this, why do the colors of the wires: phase zero earth differ from each other? After all, this is not done for beauty. That's right, beauty in a closed cable is not needed. But color is an urgent need. What's the matter?

1. Using the color designation, you can easily determine which wire should be used for what purpose. This makes it easier to switch the entire wire as a whole.
2. It is color marking that reduces the likelihood of errors during the installation process, which can lead, firstly, to a short circuit, and secondly, to electric shock during operation or repair of electrical networks.

It should be noted that the entire color range of designations for the cores of an electrical wire is summarized in the PUE, which is based on GOST R 50462. So the variety of colors is fixed by the state standard. True, we must pay tribute to the fact that the designation of the veins has not only a color application, but also a letter. But in this article we will deal with the color of the wires: phase zero ground.

Attention! Color marking is carried out along the entire length of the wire. Often, electricians will make additions to ensure that the wires are connected correctly. To do this, multi-colored cambrics are installed at the ends of the wiring sections (these are heat-shrinkable polymer tubes) or the ends are wrapped with multi-colored insulation.

Tire colors at substations

Three-phase wiring inside electrical substation determined by three colors corresponding to each individual phase. Typically, electrical busbars are painted for this purpose. So here it is:

• Phase "A" is usually yellow.
• Phase “B” – green.
• Phase “C” – red.

This is not difficult to remember, especially for young and novice electricians.

DC networks

In everyday life, direct current is not used. But on construction sites (electric cranes, various trolleys and lifts), in production, in electrified transport (trams and trolleybuses), at substations for recharging automation systems without direct current not enough.

In such networks, only two circuits are used: positive (plus) and negative (minus). That is, there are no phase conductors here, much less zero. But even then, different colors of conductors are used. So positive is colored red, negative is blue.

Please note that if a single-phase DC network is a branch from a three-phase network, then the color designation in the two networks must completely match each other and be painted according to standard requirements.

Coloring of AC networks

It is in the networks alternating current The varied colors of the wire cores create conditions under which confusion between phase and zero, between phases, as well as the ground loop completely disappears. This is especially true in cases where the installation is done by one electrician, and network maintenance is handled by another. The same applies to repair work.

Those electricians who have dealt with old electrical networks know how often they had to constantly ring the circuits, determining whether it was phase or zero. This took a lot of time and made the work very inconvenient. The whole point was that the insulation of the old wires was either white or black, that is, monochromatic. Of course, even during the USSR period, experts thought about creating a certain standard in color design. And the color marking itself changed periodically until a final standard was adopted.

Zero and ground color

In the accepted standards, there are two types of colors, which indicate the neutral conductor and the ground conductor. The first is designated by the letter “N” - this is the working zero, the second by the letters “PE” - this is the protective zero. Their colors are respectively:

• Blue.
• Yellow-green.

Please note that yellow and green stripe can be located not only along the wire, but also across it.

There are models of electrical wires in which the grounding conductor and neutral are connected into one circuit, it is designated “PEN”. Its color is yellow-green, and at the ends where the sections connect, it is blue. Or, conversely, the color is blue along the entire length, and yellow-green at the ends. The standard allows such dual designation.

Color of phase conductors

Again, referring to the rules of the PUE, it should be noted that the standard makes it possible to use a fairly wide range of colors for coloring the cores of an electrical wire. Let's list them all: black, white, brown, grey, red, pink, purple, turquoise and orange.

Attention! Since a single-phase electrical network is a branch from a three-phase network, it is necessary to maintain the same color design of the wires. That is, if in a three-phase network one of the phases is wired with a brown wire, then try to choose a two-core wire for a single-phase network also with a brown wire.

We can conclude that the color of the phase wire simply must differ from the color of the ground loops and the working zero. Of course, a single-color cable can also be used in wiring, there are no problems here. You just have to constantly install cambrics or colored insulation at the ends of the cables. It's not that difficult to carry out installation work. But as mentioned above, this will be inconvenient when the issue of repair arises. And one more point that concerns multi-colored wires. It is imperative to decide on the length of each contour: both in general and in sections. This will simplify installation; there will be no need to make intermediate joints.

Connection rules and standards are not followed - what to do?

Sometimes you have to deal with situations where the rules for connecting wires by color are not followed in the distribution board. That is, old standards were used or it was simply the negligence of the electrician who carried out the installation. What to do in this case?

There is no need to reconnect. The best option is to mark all the wires coming from the switchboard to the house or apartment. Of course, in this case, a lot of time will be spent, because you will have to open each junction box, open the wire connections and ring each loop, determining whether it is a phase (and which phase), zero or grounding. And mark all ends of the wires using colored electrical tape or cambrics. It's a lot of work, but necessary.

The production of insulation of various colors in stranded wires and cables is intended to facilitate electrical installation work. Color marking serves to unambiguously identify the core, which can significantly speed up and simplify the process of connecting a cable/wire to contacts, increase labor productivity during installation and ensure electrical safety when using products from various manufacturers.

For installation wires and cables, the uniform rules for color marking are set out in GOST 31947-2012 “Wires and cables for electrical installations for voltages up to 450/750 V inclusive. General technical conditions". In the system of interstate standardization this standard was introduced to replace GOST 6323-79 for use in the member countries of the CIS and the Customs Union. GOST 31947-2012, as a new requirement, introduced a system of mandatory uniform color marking of cores for the purpose of their identification.

According to GOST 31947-2012, insulated cores of multicore wires and cables must always have a distinctive color, and this color must be solid. Each insulated core must be the same color along its entire length, except for the core marked with a combination of green and yellow flowers. At the same time, yellow and green colors cannot be used separately - only in the “green-yellow” combination, which is used only to indicate the grounding conductor.

The preferred color scheme looks like this:

• For three-core wires and cables: green-yellow, blue, brown or brown, black, gray;
• For four-core cables: green-yellow, brown, black, gray or blue, brown, black, gray;
• For five-core cables: green-yellow, blue, brown, black, gray or blue, brown, black, gray, black.

Blue color is used to indicate the neutral core.

As for the distribution on the green-yellow colored core, the following condition must be met: on any section of the core with a length of 15 millimeters, one of specified colors shall cover at least 30% but not more than 70% of the surface of the insulated conductor, and the other color shall cover the remainder.

All colors must be easily distinguishable and durable. Under this condition, it is permissible to mark the cores by painting the top layer of insulation.

As for the sheath, which can be applied over the insulated cores of wires and cables to give the wire a flat and the cable an almost round shape, then, according to GOST 31947-2012, its color is not standardized.

For power cables, the uniform rules for color marking are set out in GOST 31996-2012 “Power cables with plastic insulation for a rated voltage of 0.66; 1 and 3 kV. General technical conditions". It was this GOST that introduced a system of mandatory uniform color marking of cores for the purpose of their identification, which was not in GOST 16442-80 (in the interstate standardization system, GOST 31996-2012 replaced GOST 16442-80).

According to GOST 31996-2012, insulated cable cores must have a distinctive color, which must be either solid or in the form of a longitudinal strip with a width of at least 1 millimeter.

The color of the insulation of the cores of multi-core cables must correspond to the following table:

Number of cores in the cable, pcs.	Core insulation color
	Core serial number
	Grey*	Blue
	Grey*	Brown	Black
	Grey*	Blue	Green- yellow
	Grey*	Brown	Black	Blue
	Grey*	Brown	Black	Green- yellow**
	Grey*	Brown	Black	Blue	Green- yellow
* Or natural. ** By agreement with the customer.

By agreement with the customer, a different color combination of insulation of the main cores is acceptable.

The insulation of single-core cables can be of any color from those given in the table - also as agreed with the customer.

The insulation of the ground conductor (PE) must be two-color, namely green-yellow, with one color covering at least 30% and no more than 70% of the insulation surface, and the other color covering the rest. The insulation of the neutral core (N) must be blue. In this case, the cable designation must necessarily indicate: the letter N - if there is a neutral core in the cable, the letters PE - if there is a grounding core, the letters N, PE - if there are both cores in the cable design. For example: VVG ng(A)-LS 3x1.5ok (N, PE)-0.66 or PPGng(A)-HF 4x95ms (N)-1.

By agreement with the customer, marking of the main insulated cores with numbers is allowed. However, even in this case, the insulation of the ground conductor must be green-yellow, the insulation of the neutral conductor must be blue, and they cannot be digitally marked.

Anyone may encounter the need to repair electrical wiring or purchase various cable products for a future new home, and the color of wires in electrical installations plays an important role. The reasons for this can be different, but when you start eliminating it, you should count on one encouraging factor: there is color coding of the wires. It’s worth figuring out what it is and why they do it.

Basic definitions

In AC electrical networks up to a thousand volts, the color marking of wires and cables is strictly regulated by state regulations, such as the “Rules for Electrical Installations” (PUE), and this is what the section of the seventh edition in Chapter 1, paragraphs 1.1.29 - 1.1.30 is responsible for. It states that “Identification of wire cores by colors or digital designations” must be used in accordance with GOST P 50462-92 (IEC 446-89). The marking has the following basic designations:

In 3-phase AC distribution boards, the busbars are painted:

• yellow – L1 (phase A);
• green – L2 (B);
• red – L3 (C);
• blue – block of neutral working conductor N;
• alternating longitudinal or transverse stripes of the same width of yellow-green color - PEN grounding bus.

Important! If the electrical panel housing also serves as a grounding contact, then the location where the wires are connected is indicated by a sign (ground) and is colored yellow-green.

The PUE allows you to designate the color of the main wires, phase and zero, not along the entire length of the bus, but only at the points of connection to the contacts; if the bus is invisible, you are allowed not to color it.

Important! When installing electrical equipment located in the same building, it is necessary to use color marking of wires and cables using the same color schemes.

We must not forget that the designation of wires by color should in no case reduce the degree of electrical safety and convenience when repairing or servicing electrical equipment.

electrical safety

Alternating electricity with a voltage of 380V - 220V is a dangerous factor, so if a person touches exposed wires or metal parts of electrical equipment that may be under this voltage without permission, it can result in severe burns or fatal injury! For this purpose, the PUE gives an answer not only to the questions: what color is the grounding wire, or what is PEN, but what is it for.

In order to protect people as much as possible from possible exposure to electric current, electrical safety systems were adopted, characterized by one or more factors, such as:

• grounding;
• protective grounding;
• separation of networks by a transformer.

To ensure safe operation in existing electrical installations up to 1 kV, five grounding systems are used: TN-C, TN-S, TN-C-S, TT, IT s different ways grounding, grounding and separation of networks. The PUE defines each of the systems as:

1. TN-C, where the working zero N and the grounding PE conductors are combined in one PEN wire. Characterized by: the use of a cable with four cores in a three-phase network and a two-core cable in a single-phase network. This is the oldest device in electrical networks and is still found everywhere for reasons of economy, for example, in street lighting.
2. TN-S, where the working N conductor and the grounding PE are separated from the supply transformer to the end consumer. Such networks are made of five-core cables for a three-phase network and three-core wires for a single-phase network.
3. TN-C-S, where there is one combined PEN conductor of a four-core cable, from the supply transformer to the group panel at the entrance to the building, which is further divided into N and PE, respectively into five and three-wire wiring. This is the most common system for constructing power supply networks for buildings and structures.
4. TT, where there is only one working N conductor, and only the electrical equipment body is grounded. In such a system, four and two-wire wiring are used, respectively. This is how overhead power lines are mainly constructed.
5. IT, where the electrical installation is separated from the power supply network by a transformer and completely isolated from the ground. This is the safest system for humans and is used only for special-purpose consumers.

Thus, the color of the wires phase and zero, L and N in electrics will help to clearly determine the security system used in a given electrical network.

DC electrical networks

Along with alternating current, direct current circuits are used, for example, in on-board networks cars and electrical appliances. In such electrical wiring there is no phase wire and neutral wire. The rule for wire color in DC electrics is much simpler, since there are only two potentials, positive, denoted in electrical diagrams, as (+) and negative, having a sign (-). The colors of such wires are easy to remember: the plus is red, and the minus is black.

Important! For household appliances, these colors are true only for the supply lines; in the further part of the circuit, the positive wire may have a different color.

Practice

Having started directly to electrical installation work or repairs in electrical wiring, you may encounter non-compliance with the color regulations, which are established by regulatory documents. As practice shows, this case is not the rule, but the exception.

Eg:

• you can buy a three-core cable of type BBG 3x1.5, which has cores with white, red and brown colors;
• cable products are often found with white wires with a colored stripe of black, gray or blue along the entire length;
• In the electrical wiring that was done before, in general, you can find a two or three-core white wire.

Here are some practical tips that will come in handy:

1. When making repairs in existing networks, it is necessary to use electrical safety devices, such as a voltage indicator or an indicator screwdriver. With their help you can always determine the color of the phase wire.
2. If the correct color marking of cable products is not available, purchase cambric or insulating tape of the required color. The main thing is to designate the color of the ground wire as yellow-green, the working zero as blue, and for phase L in the electrics you can choose any other color.
3. To install new wiring, use a cable of the same brand so that there is no confusion with the color of the wires in the electrical system.

Color coding abroad

The yellow and green marker of the grounding wire PE and the blue working zero N are designated absolutely identically in all CIS countries, while they are clearly unified with the countries of the European Union. The color designation of the phase wire varies slightly, but this is not of fundamental importance in terms of electrical safety.

In other countries, such as Brazil, the USA, Canada, Australia and New Zealand, the PE ground wire, along with the yellow-green color, can be simply green, and the working zero N is indicated by any of black, white or blue.

In the UK, Australia, New Zealand, Canada and the USA, the PE conductor may not have any insulation at all.

Important! Previously in the USSR, according to the old edition of the PUE, there was color marking that was radically different from today. Thus, the black color indicated the solidly grounded neutral and all grounding conductors, and the white color of the wire corresponded to the working zero.

It is worth remembering that electrical installation work requires an electrician to have knowledge of electrical installations and safety precautions. Once you clearly know the markings, the question of how to choose the right wire color during work will no longer arise, and repairing electrical wiring or installing equipment will become not only safe, but also convenient.

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The transition to the usual voltage of 220 V was carried out back in the years of its existence Soviet Union and ended in the late 70s, early 80s. Electrical networks of that time were made according to a two-wire circuit, and the wire insulation was monochromatic, mostly white. Subsequently, there appeared Appliances increased power, requiring grounding.

The connection diagram gradually changed to a three-wire one. GOST 7396.1–89 standardized the types of power plugs, bringing them closer to European ones. After the collapse of the USSR, new standards were adopted based on the requirements of the International Electrotechnical Commission. In particular, to increase safety when working in electrical networks and simplify installation, color grading of wires was introduced.

Normative base

The main document describing the requirements for the installation of electrical networks is GOST R 50462–2009, which is based on the IEC 60446:2007 standard. It sets out the rules that the color marking of wires must comply with. They concern manufacturers of cable products, construction and operating organizations whose activities are related to the installation of electrical networks.

Extended installation requirements are contained in the Electrical Installation Regulations. They contain the recommended connection procedure, with reference to GOST-R in paragraphs regarding color gradations.

The need for color separation

A two-wire system implies the presence of a phase and a zero in the network. The plug for such sockets is flat. The equipment is designed in such a way that the correct connection does not matter. It doesn’t matter which contact the phase is applied to, the equipment will figure itself out on its own.

With a three-wire system, an additional grounding conductor is provided. At best, not correct connection wires, will lead to constant operation of the circuit breaker, and at worst, to equipment damage and fire. The use of color gradation for cores eliminates installation errors and eliminates the need to use special instruments designed to measure the resulting voltage.

Three-wire system

Let's look at a cross-section of a three-core wire, which is used for laying household electrical networks.

The color of the wires indicates where the phase, neutral and ground are located. Additionally, the figure shows typical letter symbols used in electrical circuits. By picking up such a drawing, you can visually determine the correctness of the connection.

Let's take a look at GOST and see how well the color coding of wires shown in the figure meets the requirements. Clause 5.1 general provisions contains a description of the twelve colors that should be used for marking.

Nine colors are allocated to indicate phase wires, one for neutral and two for grounding. The standard provides for a grounding wire in a combined yellow-green design. Longitudinal and transverse application of stripes is allowed, and the predominant color should not occupy more than 70% of the braiding area. The separate use of yellow or green in a protective coating is expressly prohibited by clause 5.2.1.

This scheme is used when single-phase connection, suitable for most electrical appliances. It is almost impossible to get confused in it, with a correctly marked wire.

Five-wire system

For a three-phase connection, five-core wires are used. Accordingly, three wires are allocated for phases, one for neutral or zero and one for protective, grounding. Color marking, as in any alternating current network, is similar, in accordance with GOST requirements.

In this case important point there will be correct connection of phase conductors. As can be seen in the figure, the protective wire is made in a yellow-green braid, and the neutral wire is made in blue. Allowed shades are used for the phases.

Using five-core wires, you can connect a 380 V network with correct wiring.

Combined wires

In order to reduce the cost of production and simplify connections, two- or four-core wires are also used, in which the protective conductor is combined with the neutral conductor. In the documentation they are designated by the abbreviation PEN. As you guessed, it consists of letter designations neutral (N) and ground (PE) wires.

GOST provides special color markings for them. Along their length, they are painted in the colors of the grounding conductor, that is, yellow-green. The ends must be painted blue, which additionally marks all joints.

Since the places where the connection is made cannot be determined in advance, at these points the PEN wires are isolated using insulating tape or blue cambrics.

Non-standard wires and markings

When purchasing a new wire, you will, of course, pay attention to the color marking of the cores and choose the option where it is applied correctly. What to do if the wiring has already been completed, but the colors of the wires do not meet the requirements of GOST? The output in this case is the same as with PEN wires. You will have to perform manual marking after you have decided on the role played by the conductors suitable for the equipment. A simple option Colored electrical tape of appropriate shades will be used. At a minimum, it is worth identifying the protective and neutral wires.

During professional installation, it is possible to use special cambrics, which are hollow pieces of insulating material. They are divided into regular and heat-shrinkable. The latter do not require selection by diameter, but do not have the possibility of reuse.

There are also specially made markers with international alphanumeric designations. They are used on input and distribution boards, for example, in apartment buildings or administrative buildings.

Digital tags, together with the color of the wire, allow you to determine which consumer is supplied with power.

Additional requirements

Since lines, like wiring, can be made using various cable products, there are a number of rules for their mutual connection. The connection of a three-wire cable to a five-wire cable must be carried out in compliance with the color markings from master to slave. Accordingly, the grounding and neutral colors must match.

Phase connection, in this case, is performed using a unifying bus. On the one hand, three cores are connected to it, on the other hand - one, which will be the phase in the new branch.

When installing household electrical networks, according to safety requirements, it is prohibited to use wiring with aluminum or multi-wire conductors. Only solid copper cable should be used.

Three-wire DC system

In DC systems, a three-wire system is also used, but the purpose of the wires is different. The division is made into positive, negative and protective. According to GOST, the following color markings are used in such networks:

• Plus - brown;
• Minus - gray;
• Zero - blue.

Since it is irrational to produce separate wires for DC systems, the specified color gradation is used mainly for painting conductive busbars.

Finally

As you can see, the colors of electrical wires are not a whim of the manufacturer, but a measure aimed at ensuring safety requirements. If you follow the installation rules, it is much easier to maintain such networks, and not only an electrician, but also you and me can figure out the connection.

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