And in everyday life we use, as a rule, single-phase. This is achieved by connecting our wiring to one of the three phase wires (Figure 1), and what kind of phase comes to the apartment for us, for further consideration of the material, is deeply indifferent. Since this example is very schematic, the physical meaning of such a connection should be briefly considered (Figure 2).
An electric current arises in the presence of a closed electrical circuit, which consists of a winding (Lt) of a substation transformer (1), a connecting line (2), and the electrical wiring of our apartment (3). (Here the designation of the phase is L, zero is N).
Another point is that in order for current to flow through this circuit, at least one consumer of electricity Rn must be turned on in the apartment. Otherwise, there will be no current, but the VOLTAGE on the phase will remain.
One of the ends of the winding Lt at the substation is grounded, that is, it has electrical contact with the ground (Zml). The wire that comes from this point is zero, the other is phase.
This implies another obvious practical conclusion: the voltage between "zero" and "ground" will be close to zero (determined by the ground resistance), and "ground" - "phase", in our case 220 Volts.
Moreover, if hypothetically ( In practice, this cannot be done!) ground the neutral wire in the apartment by disconnecting it from the substation (Fig. 3), the voltage "phase" - "zero" we will have the same 220 Volts.
What is phase and zero figured out. Let's talk about grounding. The physical meaning of it, I think, is already clear, so I propose to look at it from a practical point of view.
If for some reason an electrical contact occurs between the phase and the conductive (metal, for example) body of the electrical appliance, voltage appears on the latter.
When this body is touched, an electric current can flow through the body. This is due to the presence of electrical contact between the body and the "ground" (Fig. 4). The lower the resistance of this contact (damp or metal floor, direct contact building structure with natural grounding conductors (heating batteries, metal water pipes) the more danger you face.
The solution to this problem is to ground the case (Figure 5), while the dangerous current "leaves" through the ground circuit.
Structurally, the implementation of this method of protection against defeat electric shock for apartments office space consists in laying a separate grounding conductor PE (Fig. 6), which is subsequently grounded in one way or another.
How this is done is a topic for a separate conversation, for example, in a private house you can make a ground loop yourself. Exists various options with its advantages and disadvantages, but for further understanding of this material they are not fundamental, since I propose to consider several purely practical issues.
HOW TO DEFINE PHASE AND ZERO
Where is the phase, where is zero - a question that arises when connecting any electrical device.
To begin with, let's look at how to find phase. The easiest way to do this is with an indicator screwdriver (Figure 7).
With a conductive tip of the indicator screwdriver (1) we touch the controlled section of the electrical circuit (during operation, the contact of this part of the screwdriver with the body is unacceptable!), touch the contact pad 3 with the finger of the hand, the glow of the indicator 2 indicates the presence of a phase.
In addition to the indicator screwdriver, the phase can be checked with a multimeter (tester), although this is more laborious. To do this, the multimeter should be switched to the AC voltage measurement mode with a limit of more than 220 volts. With one multimeter probe (it doesn’t matter which one) we touch the section of the measured circuit, with the other - the natural ground electrode (heating batteries, metal water pipes). With the readings of the multimeter corresponding to the mains voltage (about 220 V), there is a phase on the measured section of the circuit (diagram Fig. 8).
I draw your attention - if the measurements taken show the absence of a phase, it is impossible to assert that this is zero. An example is in Figure 9.
- Now there is no phase 1 at the point.
- When switch S is closed, it appears.
Therefore, you should check all possible options.
I want to note that if there is a ground wire in the electrical wiring, it is impossible to distinguish it from the neutral conductor by electrical measurements within the apartment. As a rule, the wire that is used for grounding has a yellow green color, but it is better to verify this visually, for example, remove the socket cover and see which wire is connected to the ground contacts.
© 2012-2019 All rights reserved.
All materials presented on this site are for informational purposes only and cannot be used as guidelines and normative documents.
A circuit diagram is required for the installation or repair of an electrical network. It is difficult for an ignorant person to understand the meaning of the symbols with which the equipment connection plan is saturated. To understand the purpose of the wires will help the designation of the phase and zero on English language.
Purpose of wires in wiring
From the power source to the consumer, electricity is transmitted through stranded wires. Devices and mechanisms are provided with energy through at least three lines. Voltage is supplied through the phase and neutral cables. The ground wire protects a person from electric shock.
Each line on the wiring diagrams is designated in a certain way. Cables marked with the letters n and l in electrical engineering are designed to carry current. "Earth" is marked with the abbreviation PE, which stands for Protective Earth and translates as "protective earth".
Wires intended for phase, zero and ground have a specific color and marking.
The difference in appearance makes it easier to assemble the network and prevents electricians from making mistakes that lead to an accident or damage to the device.
Phase line
Network operation alternating current form two components - the working phase and the zero component. The working phase, or simply phase, is the main conductor in a multicore cable. This line supplies power to the device.
In the electrical documentation, the phase channel is denoted by the Latin letter L. The use of a lowercase letter l is allowed. Professionals give conditional reduction different meanings. Preferred Options are considered Lead, Live or Line. From English, the words are translated respectively as "leading wire", "voltage" or "line".
If the circuit provides for the use of several phase cables, then the phase number is added to the letter. According to European standards that do not allow color changes, phase wires are painted in specific colors:
- L 1 - brown.
- L 2 - black.
- L 3 - grey.
In household wiring for 220 volts, 3 lines are used to connect zero, ground and voltage. Therefore, the only phase bus is covered with insulation Brown. The use of cables of a different color is considered a gross violation of technological standards.
Zero notation
In an alternating current circuit, the neutral line is necessary to create a closed circuit of the voltage drop across the contacts electrical appliance. Together with the working phase "null" is the main component of the network.
On the circuit diagrams, the zero phase is indicated by the letters of the Latin alphabet N or n. The abbreviation implies the concepts of Null or Neutral. Dictionaries give translations of "Null" and "Neutral".
Depending on the flexibility of the cable, the color of the neutral conductor is presented in options of blue color. Rigid single-core bus has saturated shade ultramarine. The insulating layer of the stranded wire is colored light blue.
Amateur craftsmen sometimes connect neutral and ground, mistakenly believing that they are one and the same. Dangerous delusion leads to sad consequences. Zero phase and ground bus perform different functions from each other.
The coloring is also different. The protective conductor is green-yellow. Connecting tires for various purposes in one line is strictly prohibited by safety regulations.
Precautionary measures
Proper wiring is carried out in accordance with the IEC 60445 regulation, adopted by European law in 2010. Norms of the Russian GOST 50462−2009, which correspond to international rules, indicate the color of the wires "phase", "zero" and "ground".
Sometimes electricians have to work with networks that have been installed many years ago, and the wiring plan has been lost. Absence circuit diagram makes it useless to know how zero and phase are denoted. The task of an electrician will become more complicated if wires with an insulation color that does not comply with GOST are used in the circuit.
Before starting work, the installer must determine the purpose of each line using a test lamp, indicator screwdriver or multimeter. When ringing electrical circuits basic safety rules must be followed:
- manipulations with an indicator screwdriver are performed with one hand;
- free hand can't touch metal structures or walls;
- work is carried out in the presence of a qualified assistant.
Having found out which wire is intended for what, an experienced specialist marks the lines. For this, special adhesive-based tags or PVC nozzles are used. On the surface of the marking material applied conventions in English - n, l or PE. Only after the completion of the identification work, they begin to install or repair electrical equipment.
Understanding the meaning of the Latin letters l and n on the diagram helps the electrician to install and repair the network faster and better. In addition, the letter designation of the phase and zero on the diagram, as well as color marking, clearly determine the purpose of the wire with which the master works. This prevents accidents in the workplace.
If the contacts are connected incorrectly by color, this can cause such adverse consequences as electric shock and electric shock to a person.
The main purpose of color coding is to create safe conditions electrical work, as well as reducing the time it takes to find and connect contacts. Today, according to the PUE and existing European standards, each core has its own insulation color. About what color the wire is phase, zero, earth, we will talk further!
What does grounding look like?
According to the PUE, the insulation of the "earth" should be painted in a yellow-green tint. Please note that the manufacturer also applies yellow-green stripes to the ground wire in the transverse and longitudinal directions. In some cases, the shell may be pure yellow or pure green. On the wiring diagram grounding is usually denoted by the Latin letters "PE". Very often, "ground" is called zero protection, do not confuse it with zero worker (zero)!
Appearance
Graphic image on the diagram
What does neutral look like?
In a three-phase and single-phase electrical network, the zero color should be blue or light blue. On the electrical circuit, "0" is usually denoted by the Latin letter "N". Zero is also commonly called a neutral or zero working contact!
Standard color Indication of the neutral on the wiring diagram
What does a phase look like?
The marking of the phase wire (L) by the manufacturer can be carried out in one of the following colors:
- black;
- White;
- grey;
- Red;
- Brown;
- Orange;
- Violet;
- pink;
- turquoise.
Most often, the color of the phase wire is brown, black and white.
Sheath color Wiring diagram
It's important to know!
The color coding of wires in electrics has many features and often beginners are faced with 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 the phase, ground, zero?”;
- "What other standards exist for the color of the insulation?".
To all these questions, we will now briefly give a simple explanation!
What is PEN?
The now obsolete TN-C earthing system involves the use of a combination of neutral and earth. The advantage of such a system is the ease of electrical work. The disadvantage is the threat of electric shock at either the apartment.
The color of the combined wire is yellow-green (like PE), but at the same time, at the ends, the insulation has a blue color, characteristic of the neutral. On the electrical circuit, the combined contact is indicated by three Latin letters - "PEN".
Indication "PEN" on the wiring 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 were of the same color. How in this case to find out which wire means what?
If a single-phase network is presented without a "ground" (2 cores), then all you need is a special indicator screwdriver. With its help, you can easily determine where is 0 and where is the phase. About what we talked about. First, turn off the power supply on the shield. Next, we clean the two conductors and breed apart from each other. After that, turn on the electricity supply and carefully determine the phase / zero using the indicator. If, upon contact with the core, the light bulb lights up, this is a phase, respectively, the second core is zero.
In the event that the wiring has a ground wire, equipment such as a multimeter must be used. This device has two tentacles. First you need to set the AC measurement range to over 220 volts. Next, we fix one tentacle on the phase contact, and with the help of the second tentacle we determine zero / ground. When in contact with 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 way to determine. If there is no multimeter and an indicator screwdriver at hand, then you can try to determine what color the wires L and N are by their insulation. In this case, remember that the blue shell is always ZERO. In any non-standard marking, the color of the zero does not change. The other two strands will be a bit more difficult to identify.
Associations first. You see the remaining color and black or white contact. In the old good times the ground was marked with black or white insulation. It is quite reasonable to assume that it is she, the remaining color - phase (L).
Second option. Zero, again, we immediately recline, there remains a red and black / white wire. If the isolation white color, then according to the PUE, this is a phase. So 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 during either the outlet!
I would also like to note the very important nuance — in DC circuit color marking of plus and minus is represented by black (-) and red (+) insulation color. Concerning three-phase network(for example, on transformers), here all three phases have their own individual color: phase A is yellow, B is green, C is red. Zero, as usual, is blue, and ground is yellow-green. In the 380V cable, wire A is white, B is black, C is red. Zero working and protective conductors do not differ from the previous color marking.
How to specify L, N, PE yourself?
In the event that there is no visual designation or differs from the standard one, it is recommended to indicate all the elements yourself after repair work. To do this, you can use colored electrical tape or a special product - heat shrink tube also called cambric. According to the requirements of the PUE, GOST and generally accepted recommendations, the indication of the cores must be carried out at the ends of the conductor - at the points of its connection with the bus (as shown in the photo).
Small notes on colors will facilitate repair and maintenance for both you and the electrician, who will probably repair the home electrical network after you! About that, we told in a separate article.
Existing Factory Standards
The designation of insulation changes slightly every decade, so it is possible this information You'll need it.
Until 2000, the following color marking of wires was used:
- white - N;
- black - PE;
- bright - L.
A few years after this standard, a significant change was made: PE was "repainted" in yellow-green color (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 bring to your attention a detailed decoding of the marking of wires and cables by color, which today complies with European and domestic standards:
In progress self installation and connecting electrical equipment (this can be various lamps, ventilation, electric stoves, etc.), you can see that the switching terminals are marked with the letters L, N, PE. Of particular importance here is the marking L and N. In addition to the designation of wires in an electrician by letter, they are placed in insulation of various colors.
This greatly simplifies the procedure for determining where the phase, ground or neutral wire is located. In order for the device to be installed to work in normal mode, each of these wires must be connected to the appropriate terminal.
Designation of wires in an electrician by letters
Electrical communications in the domestic and industrial sectors are organized by means of insulated cables, inside of which there are conductive cores. They differ from each other in the color of the insulation and marking. The designation of l and n in electrics makes it possible to expedite the implementation of installation and repair measures by an order of magnitude.
The application of this marking is regulated by a special GOST R 50462: this applies to electrical installations where voltage up to 1000 V.
As a rule, they are equipped with a dead-earthed neutral. Often, residential, administrative and business facilities have electrical equipment of this type. During the installation of electrical networks in buildings of this type, it is necessary to be well versed in color and letter indications.
Phase designation (L)
The AC network includes live wires. Their correct name is "phase". This word has English roots, and is translated as "line" or "active wire". Phase conductors carry a particular danger to human health and property. For safe operation, they are covered with reliable insulation.
Usage bare wires voltage is fraught with the following consequences:
- 1. Electric shock to people. These can be burns, injuries, and even death.
- 2. The occurrence of fires.
- 3. Equipment damage.
At designation of wires in electrical phase conductors are marked with the letter "L". It's an abbreviation English term" Line", Or" line"(Another name for phase wires).
There are other versions of the origin of this marking. Some experts believe that the words “Lead” (supply conductor) and Live (indication of voltage) became the prototype. A similar marking is also used to indicate the clamps and terminals to which the line wires should be switched. For example, in three-phase networks, each of the lines is also marked with the corresponding number (L1, L2 and L3).
The current domestic regulations governing the designation of phase and zero in electrics (GOST R 50462-2009) require that linear conductors be placed in brown or black insulation. Although in practice the phase wires can be white, pink, gray, etc. In this case, it all depends on the manufacturer and the insulating material.
Zero notation (N)
To mark the neutral or zero working core of the network, use the letter "N". This is an abbreviation of the term neutral(translated as neutral). So all over the world it is customary to call the zero conductor. In our country, the word “Zero” is mainly used.
Most likely, the word Null is taken as the basis here. The letter "N" in the diagram indicates the contacts or terminals intended for switching the neutral core. A similar designation is accepted for both single-phase and three-phase circuits. As a color designation for the neutral wire, blue or white-blue (white-blue) insulation is used.
Earth symbol (PE)
In addition to the designation of phase and zero, a special letter designation PE (Protective Earthing) is also used in electrics for the ground wire. As a rule, they are always included in the cable, along with zero and phase conductors. Contacts and clamps intended for switching with a grounding neutral wire are also marked in a similar way.
For ease of installation, the conductors for grounding are placed in yellow-green insulation. Home master must understand that these colors always indicate only ground wires. To indicate phase and zero in electrics, yellow and green are never used.
As practice shows, when organizing electrical networks in buildings of the residential sector, violations of the generally accepted standards for the use of insulation color and the corresponding alphanumeric marking are sometimes allowed. In this case, it is not always enough to have the ability to decipher the designations L, N or PE.
In order for the connection of electrical equipment to be truly safe, it is necessary to check the conformity of the marking with the real state of affairs. To do this, use special devices (testers) or improvised devices. In the absence of experience in such work, for your own safety, it is better to invite an experienced electrician with the appropriate permission.
The designation of l and n in electrics
Designation of phase and zero in electrics introduced in order to Electricity of the net were safe and easy to use. For this, a special letter marking (l and n) and insulation of the corresponding color. There may also be PE-marked cores in yellow-green color: this is how the ground wires are marked.
In addition, the same letter designations are used on the connecting contacts and terminals. All that needs to be done during the installation of the electrical appliance is to bring each of the wires to the terminal. For reinsurance, it is advisable to check each of the wires with a tester.
Anyone who has ever dealt with wires and electrics noticed that conductors always have different color isolation. It's not just done. The colors of the wires in electrics are designed to make it easier to recognize the phase, neutral wire and ground. All of them have a certain color and are easily distinguished during operation. What is the color of the wires phase, zero, ground and will be discussed further.
How phase wires are painted
When working with wiring, the phase wires are the most dangerous. Touching the phase, under certain circumstances, can become lethal, therefore, probably, bright colours. In general, the colors of wires in electrics allow you to quickly determine which of the bundle of wires is the most dangerous and work with them very carefully.
Most often, phase conductors are red or black, but there is also another color: brown, lilac, orange, pink, purple, white, gray. Here in all these colors phases can be painted. It will be easier to deal with them if we exclude the neutral wire and ground.
In the diagrams, phase wires are indicated by the Latin (English) letter L. If there are several phases, a numerical designation is added to the letter: L1, L2, L3 for a three-phase 380 V network. In another version, the first phase is indicated by the letter A, the second - B, the third - C .
Ground wire color
By modern standards, the ground conductor is yellow-green. It usually looks like yellow insulation with one or two longitudinal bright green stripes. But there are also coloring of transverse yellow-green stripes.
In some cases, only yellow or bright green conductors may be in the cable. In this case, the "earth" has exactly this color. It is displayed in the same colors on the diagrams - more often bright green, but it can also be yellow. Signed on the diagrams or on the equipment "earth" in Latin (English) letters PE. The contacts to which the "earth" wire must be connected are also marked.
Sometimes professionals call the ground wire "zero protective", but do not confuse. It is earth, and it is protective because it reduces the risk of electric shock.
What color is the neutral wire
Zero or neutral is blue or blue, sometimes blue with a white stripe. Other colors in electrics are not used to indicate zero. So it will be in any cable: three-core, five-core or with large quantity conductors.
In blue, they usually draw "zero" on the diagrams, and sign it with the Latin letter N. Experts call it the working zero, since, unlike grounding, it participates in the formation of the power supply circuit. When reading a circuit, it is often defined as "minus", while the phase is considered "plus".
How to check the correct labeling and wiring
The colors of wires in electrics are designed to speed up the identification of conductors, but relying only on colors is dangerous - they could be connected incorrectly. Therefore, before starting work, it is worth making sure that you have correctly identified their belonging.
We take a multimeter and / or an indicator screwdriver. It is easy to work with a screwdriver: when you touch the phase, the LED mounted in the case lights up. So it will be easy to determine the phase conductors. If the cable is two-core, there are no problems - the second conductor is zero. But if the wire is three-core, you need a multimeter or tester - with their help we will determine which of the remaining two phases, which is zero.
We set the switch on the device so that the jackal is more than 220 V. Then we take two probes, hold them by plastic handles, gently touch the metal rod of one probe to the found phase wire, the second - to the expected zero. The screen should show 220 V or current voltage. In fact, it can be much lower - these are our realities.
If 220 V or a little more is displayed, this is zero, and the other wire is presumably "ground". If the value is less, we continue the check. With one probe, we touch the phase again, with the second - to the intended ground. If the meter reading is lower than the first measurement, you have the "ground" in front of you and it should be green. If the readings turned out to be higher, then somewhere they messed up with and in front of you “zero”. In such a situation, there are two options: look for exactly where the wires were connected incorrectly (preferably) or simply move on, remembering or noting the existing situation.
So, remember that when the phase-zero pair rings, the multimeter readings are always higher than when the phase-ground pair rings.
And, in conclusion, let me give you advice: when laying wiring and connecting wires, always connect conductors of the same color, do not confuse them. This can lead to disastrous results - at best, to the failure of the equipment, but there may be injuries and fires.