Generators that produce electricity at power plants have three windings, one end of which is connected together, and this common wire is called Zero. The remaining three free ends of the windings are called In phases.

Wire colors and designations

In order to find the phase, neutral and ground wires of electrical wiring without instruments, they are covered with insulation of different colors in accordance with the rules of the PUE.

The photo shows the color coding electric cable for single-phase electrical wiring voltage AC 220 V.

This photo shows the color coding of an electrical cable for 380V AC three-phase wiring.

According to the presented diagrams, wires began to be marked in Russia in 2011. In the USSR, the color marking was different, which must be taken into account when searching for phase and zero when connecting installation electrical products to old electrical wiring.

Wire color coding table before and after 2011

The table shows the color coding of wires electrical wiring, adopted in the USSR and Russia.
In some other countries the color coding is different except yellow - green wires. There is no international standard yet.

The designations L1, L2 and L3 do not indicate the same phase wire. The voltage between these wires is 380 V. Between any of the phase and neutral wires, the voltage is 220 V, and it is supplied to the electrical wiring of the house or apartment.

What is the difference between N and PE wires in electrical wiring?

According to modern PUE requirements In addition to the phase and neutral wires, a grounding wire must also be supplied to the apartment yellow - green.

The neutral N and grounding PE wires are connected to one grounded bus of the panel in the entrance of the house. But they perform different functions. The neutral wire is intended for electrical wiring, and the grounding wire is intended to protect people from electric shock and is connected to the housings of electrical appliances through the third contact of the electrical plug. If an insulation breakdown occurs and a phase gets into the body of an electrical device, then all the current will flow through the grounding wire, the fuse links will burn out or the circuit breaker will trip, and the person will not be harmed.

If the electrical wiring is laid indoors with a cable without color marking, it is impossible to determine where the neutral conductor is and where the grounding conductor is, since the resistance between the wires is hundredths of an ohm. The only clue can be the fact that the neutral wire is inserted into the electric meter, and the grounding wire passes by the meter.

Attention! Touching bare parts of the circuit connected to electrical network may cause electric shock.

Probe indicators for searching for phase and zero

A device designed to find zero and phase is called an indicator. Wide Application received light indicators for determining the phase of neon light bulbs. Low price, high reliability, long term services. IN lately LED indicators also appeared. They are more expensive and require additional batteries.

On a neon light bulb

It is a dielectric case, inside of which there is a resistor and a neon light bulb. Touching the electrical wiring wires one by one with the screwdriver end of the indicator, you find the phase by the glow of the neon light bulb. If the light bulb lights up when touched, it means it is a phase wire. If it doesn't light up, it means it's a neutral wire.

Indicator housings come in different forms, flowers, but the filling is the same for all. To prevent an accidental short circuit, I advise you to put a tube made of insulating material on the screwdriver shaft. The indicator should not be used to unscrew or tighten the screws with great force. The indicator body is made of soft plastic, the screwdriver shaft is pressed in shallowly and the body breaks under heavy load.

LED probe indicator

Indicator-probes for determining the phase on LEDs appeared relatively recently and are gaining increasing popularity, as they allow not only to find the phase, but also to test circuits, check the serviceability of incandescent light bulbs, heating elements household appliances, switches, network cables and much more. There are models with which you can determine the location of electrical wires in the walls (so as not to damage them when drilling) and, if necessary, find the place of their damage.

Design LED indicator-probe, the same as on a neon light bulb. Only instead of it, active elements are used (field-effect transistor or microcircuit), an LED and several small batteries DC. The batteries last for several years.

To find the phase, the LED indicator-probe and its screwdriver end are touched sequentially to the conductors, while You cannot touch the metal pad at the end with your hand. This area is used only when checking the integrity of electrical circuits. If, when searching for a phase, you touch this pad, the LED will also light when you touch the neutral wire with the indicator!

A brightly lit LED will indicate the presence of a phase. According to the rules, the phase wire should be on the right side of the socket. How to check contacts and circuits with such a probe indicator is described in detail in the instructions supplied with it.

How to make a probe indicator yourself
to find phase and zero on a neon light bulb

If necessary, you can make a probe indicator with your own hands to search and determine the phase.

To do this, you need to connect to one of the terminals of any neon light bulb, even a starter from a lamp daylight, solder a resistor with a nominal value of 1.5-2 MΩ and put an insulating tube on it.

A light bulb with a resistor can be placed in the handle of a screwdriver or the housing from ballpoint pen. Then appearance a homemade probe indicator will differ little from the industrial design.

Searching or determining the phase is performed in exactly the same way as with an industrial probe indicator. Holding the light bulb by the base, touch the end of the resistor to the conductor.

When selecting a resistor, sometimes difficulties arise in determining its value if colored rings are applied to the resistor body instead of a number. An online calculator will help you cope with this task.

Why does the indicator light up?
when touching the neutral wire

I have been asked this question many times. One of the reasons is the incorrect use of the LED indicator. How to properly hold the LED probe indicator when searching for a phase is written in the article above.

The second possible reason for this behavior of the indicator is a break in the neutral wire. For example, a circuit breaker installed after the meter on the neutral wire tripped. In old apartments this is not uncommon and is a gross violation of the electrical wiring. Required in mandatory remove the machine from the neutral wire or short-circuit its terminals with a jumper.

If the neutral wire breaks through devices connected to the electrical network, for example, through a switch backlight indicator, a TV in standby mode, any charger, the computer and other electrical appliances are turned off only with the start button, the phase arrives. The indicator shows this. In this case, the neutral wire can be dangerous and touching it is unacceptable. It is necessary to find and repair a break in the neutral wire, which may also be located in junction boxes.

How to find phase and zero using an electrician's test

To check the presence of supply voltage in the electrical network, electricians previously used a homemade tester, which was a low-power incandescent light bulb screwed into an electric socket. Two conductors from stranded wire about 50 cm long.

In order to check the presence of voltage, you need to touch the electrical wiring wires with the test conductors. If the light comes on, there is voltage.

An electrician's inspection of a light bulb requires careful handling and takes up a lot of space. It is much more convenient to do an electrician’s check on the LED according to the diagram below.

The circuit is simple; a current-limiting resistor is connected in series with any LED. LED of any type and color. Use it in the same way as an electrician's control on a light bulb.

The LED and resistor can be placed in a ballpoint pen housing of a suitable size. In the photo there is a control for the motorist. The control scheme is the same. Only depending on the type of LED used, resistor R1 is set to a value of about 1 kOhm.

It’s easy to check the presence of voltage on the wires in the car’s on-board network using such a tester; the right end is connected to ground according to the diagram, and the left end touches any contact. If there is voltage at the contact, the LED will light up. If you touch the positive terminal of the battery with one end of the fuse, and touch the other with the control, then if the LED does not light, it means the fuse is broken. This way you can check both incandescent light bulbs and the presence of contact in the switches.

Phase search in the presence of neutral and ground conductors

If you need to find a phase in an electrical wiring that has phase, neutral and ground wires, then using a tester this is easy to do. It is enough to make three touches with the control wires. You need to assign a conditional number to each wire, for example 1, 2 and 3 and in turn touch the pairs of wires 1 - 2, 2 - 3, 3 - 1.

The following behavior of the light bulb is possible. If when you touch 1 - 2 the light does not light up, it means the wire is 3-phase. If it lights up when you touch 2 - 3 and 3 - 1, it means 3 phase. The meaning is simple: when you touch the neutral and grounding conductors, the light will not shine, since practically these are conductors connected together on the shield.

Instead of testing, you can turn on any AC voltmeter designed to measure a voltage of at least 300 V. If you touch the phase wire, and others to zero or ground, then the voltmeter will show the voltage of the supply network.

Search for phase and zero using a control

Attention, touching any exposed conductors while searching for a phase with a tester may result in electric shock.

Everything is done very simply, one end of the control wire is connected to a pipe stripped to metal central heating or water supply, and take turns touching the wires or electrical contacts with others. When you touch the phase wire, the light bulb will light up.

If you cannot reach the metal of the pipe, you can use water flowing from the mixer. To do this, turn on the water and place one control wire under running water as close to the mixer as possible. Touch the other end of the wire to the electrical wiring. The weak light of the light bulb will tell you where the phase is.

It is best to screw in the lowest-power light bulb into the control; I used a 7.5 W refrigerator light bulb. In order to reach the water, you can use a piece of any wire or a standard extension cord.

Finding phase and zero with a voltmeter or multimeter

Finding the phase with a voltmeter or multimeter is carried out in the same way as with an electrician’s test, only instead of the ends of the test, the probes of the device are connected.

To determine zero in three-phase network Using a tester or multimeter, it is enough to measure the voltage between the wires, which between phases will be equal to 380 V, and between zero and any of the phases - 220 V. That is, the wire relative to which the voltmeter will show 220 V on the other three is zero.

Finding phase and zero using potatoes

If you don't have it on hand technical means to find the phase, then you can successfully use an exotic or folk, or there is no other way to call it, method of determining the phase, using potatoes. Don't think this is a joke. For some this may be the only thing available method, which can be successfully applied in practice.

The end of one conductor must be connected to water pipe(if it is not plastic) or a heating battery. If the pipe is painted, then the connection point must be stripped down to metal to ensure electrical contact. Insert its opposite end into the cut of the potato. The other conductor is also stuck at one end at the maximum distance from the previous one into the potato, and the other end is touched in turn to the electrical wiring wires through a resistor with a nominal value of at least 1 MΩ. You need to wait for some time. If there is no reaction on the potato cut, it is zero; if there is, it is a phase. I do not recommend using this method if you do not know the safety rules for working with electrical installations.

As you can see in the photo around the wires when connecting the electrical wiring to the phase wire, changes occurred on the cut surface of the potato. When touching the neutral wire there will be no reaction.

Installation of new equipment with partial replacement electrical wiring or without it necessarily includes a clear definition of wires with phase, “zero” and ground. There are no questions about finding the phase: use a screwdriver with a built-in indicator. If the facility uses wiring with two cores, then it is automatically clear that the first is a “phase”, the second is a “zero”. Difficulties arise when working with systems consisting of three current-carrying cables, so below we talk about how to distinguish “zero” from grounding.

The problems are related to virtually the same electrical parameters two conductors. That is why do not try to distinguish “zero” from “ground” using a regular light bulb: it will glow in both cases. The voltage values ​​will be approximately identical when measured with a multimeter on phase-zero and phase-ground pairs (about 220 V). However, this method is still relevant for certain situations.

220V control lamp

Determining the phase

To find the “phase”, just use an indicator screwdriver - simple tool, which any owner should have. Touch each conductor with the tip while keeping your finger on the top, metal part of the screwdriver handle. When the indicator light inside the screwdriver lights up, it means you have touched a phase wire. However, remember that when performing the corresponding operations, the electrical network is not de-energized.

Searching for a phase wire with an indicator screwdriver

Determination methods

There are several ways to distinguish “zero” from “ground”.

Wire color coding

Professional and conscientious electricians will never install wiring without observing color coding. Provided that the installation was carried out in compliance with the basic rules of the Electrical Installation Code, each conductor has a specific color depending on the function performed:

1. Blue/cyan sheath is used for marking neutral conductor.
2. The yellow-green sheath (stripes) is used to indicate the grounding conductor.
3. It is more difficult with a phase wire, since it can have a sheath of white, black, red, orange and other colors. Regardless of the chosen “phase” color, this installation will be correct.

Blue is marked zero, green-yellow is ground, red is phase

Remember: even if cores of the corresponding colors have been discovered, by which “phase”, “zero” and “ground” can be determined, you should not rush to conclusions. You can be completely confident in the correct installation only if you have done it yourself. In other situations, such a method of searching for “zero” and “ground” will be incorrect. So move on to the other methods.

Differential current

It is much easier to distinguish “zero” from “ground” if there is a residual current device (RCD) or differential circuit breaker in the serviced area. Use a lamp with wires, connect the device to a phase and one of two conductors. If the protection does not work, then the light bulb is connected correctly - to the phase-zero pair. If the RCD was triggered and the branch was de-energized, then the phase-ground pair was involved.

If the RCD does not work in both cases, then there may be problems with the functionality of the equipment. The performance of the differential protection device can be judged by the test performed. Any such equipment has a “Test” button. Click on it.

Note. Safety device may not work for another reason: if the current flowing through the lamp is below the rated differential value (at which the equipment must de-energize the circuit). For example, an incandescent lamp passes a current of about 20-40 mA. If a 100 mA RCD is used, then it is logical that the device will not work.

Grounding contacts on sockets

This method is suitable for any facility that uses a two-pole input circuit breaker and grounding sockets. Turn off the machine, which ensures that there is no connection between zero and ground. Do the same with all household appliances. Take a multimeter, activate the “Test” mode and perform the procedure between the ground pin on the outlet and two unknown wires.

When the ground contact of the socket is connected to “zero”, the multimeter will show a huge resistance, with “ground” - close to zero value. This method will help ensure that the grounding sockets are connected correctly.

Using a Multimeter

Before checking live wires with a multimeter, you should clean the wiring. Do not forget about safety precautions and be sure to de-energize the electrical network at the facility being serviced.

If the electrical wiring does not have color/symbol markings or the installation was performed by an unknown technician, then use a multimeter. However, first use an indicator screwdriver to determine the “phase”. Set up the multimeter by selecting the AC voltage measurement range of more than 220 V. You can take meter any type. The specific size of the range does not matter: the main thing is to set it above 220 V.

On the phase-ground pair the voltage will be less

Connect the “phase” through the multimeter to one and then to the other conductor. On a phase-zero pair, the voltage value will not be much higher than on a phase-ground pair. This will allow you to distinguish “zero” from “ground”.

Note. Determining “ground” using a multimeter is relevant for older electrical networks built according to the CT configuration. For modern TN-C-S topologies, the method is irrelevant. In the second case, the neutral and grounding conductors are separated inside the building, therefore they are electrically identical and interconnected. They have the same resistance, which means that when using a multimeter on both pairs there will be an equal potential difference.

A multimeter is not suitable for searching for a grounding conductor in a TN-S electrical network. “Zero” and “ground” are separated from the energy source to the consumer. Because of different lengths wires will have a completely different resistance, which causes the resulting difference in voltage. It may turn out that the potential difference on the phase-ground pair will be higher than on the phase-zero pair.

Disconnecting the neutral wire (electrical panel)

Make sure electrical appliances were disconnected from the network, so that current is guaranteed not to flow to the neutral conductor. Look into the distribution panel, the location of which is regulated by the PUE rules, disconnect the neutral wire (unscrew the clamps, pull the cable out input machine and insulate). Or remove the conductor from the neutral bus, which is used for further branching of the neutral. There will be two working conductors left in the apartment or private house - grounding and phase.

Pick up the multimeter again, measure the voltage between the phase (determined with an indicator screwdriver) and the other two conductors. The voltage will appear exclusively between the “phase” and “ground”, since the neutral wire is disconnected from the panel.

Note. There is such a thing as “induced voltage”. Without going into details, we note that as a result, when measuring a phase-zero pair, the multimeter will show a voltage different from “0” (usually no more than 10 V).

Dialing method

Dialing is one of the most popular methods used by craftsmen to find places where electrical wiring is broken. It is suitable for determining "zero" and "ground". This method is relevant provided that you know the location of the neutral and ground conductors at one end. For example, when a call is made from distribution panel, but for some reason at the other end the wires have a different color marking (or the same color).

Perform a complete blackout. Dialing can be done with professional instruments (any multimeter model has a corresponding function) or with a conventional circuit consisting of a light bulb, battery and wires.

If the length of the measured conductors is short, then use a piece of cable, connecting the section to the ends of the section. If you need to ring the conductor running from the distribution panel to the socket in the back room, then it is better to use a known conductor: before turning off the power, use an indicator screwdriver to determine and mark the “phase” (at both ends).

Connect one probe of a multimeter (or a homemade device) to the marked phase wire, the other to one, and then to another unknown conductor. Move to the opposite end of the line. Connect the two ends of the unidentified cores alternately to the marked phase cable. Label them.

Difference between zero and ground

The consequences of incorrect switching of the neutral and grounding conductors can be different:

1. Incorrect operation of electricity meters down or up. Accordingly, in the first case, when the supplier company finds an error, a huge fine may be assessed.
2. Incorrect operation of residual current devices and differential circuit breakers: with significant voltage drops, household appliances will constantly burn out.
3. Lack of human protection from electric shock. Moreover, the wrong design can be the main cause of the impact.

The article discussed ways to distinguish between neutral and grounding conductors in three-wire systems. They are arranged in order of increasing complexity of actions. Only correct installation of electrical wiring guarantees the correct operation of RCDs, differential circuit breakers and sockets with a grounding circuit. If there is the slightest doubt, it is better to seek help from a qualified specialist who can provide a certificate of repair work.

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According to the rules for the installation of electrical installations (PUE, the main document of all electricians) - electrical wires for various purposes must have different color markings. And if the wiring in your apartment was done by a competent specialist, then when you open the separation box, you will see wires of different colors.

• The earth will be yellow, green or yellow-green.
• Zero will be blue or cyan.
• The phase received the richest palette; it can be gray and red, pink and turquoise, orange and purple, but most often brown, black or white.

But sometimes home handyman An unpleasant surprise awaits you in the form of wires of the same color. Or even worse - wires of one color stretch from the panel to the apartment, and another color inside the room. How to understand the intricacies of wires?

It is best to invite a qualified electrician; electricity is an insidious and dangerous thing. But if you are absolutely confident in your caution and accuracy, go for it!

We are looking for a phase

First of all, turn off the power supply to the apartment at the electrical panel. All switches must be turned off! Then you need to get to the wires by removing the sealing frame and unscrewing the socket.

Important point! After disconnecting the wires from the outlet, be sure to separate them in different directions.

After this, you can free the wires from insulation and, having supplied voltage to the apartment, begin searching for the phase using indicator screwdriver. Hold the tool only by the protective housing, positioned index finger on the metal end of the handle. Touch the tip of the screwdriver to the wires one by one. The phase is the one at which the indicator lights up. If the wire is two-wire, this is enough: the second conductor is zero. In the case of a three-wire one, you will have to continue your research using a multimeter.

Looking for land

A multimeter is a combined electrical measuring instrument that combines the functions of a voltmeter, ammeter and ohmmeter. You need to turn on the multimeter to measure alternating voltage in the range above 220 volts. With one of the probes of the device we touch the previously found phase, with the other - first to one of the unidentified wires, then to the other. Let's see what voltage value the multimeter shows in each case. 220 volts corresponds to zero, when touching the ground the value will be less.

By the way, you can also determine the phase using a multimeter. The measurement range will be the same - above 220 volts. Using the probe, which extends from the socket marked V, we touch the wires one by one. The phase will signal itself with an indicator of 8–15 volts, and zero - zero on the scale of the device.

During repairs, there are often cases when there is a need to change, install or connect sockets, switches, as well as all kinds of equipment directly to the network. In such situations, it is important to be able to determine the location of the wires with phase, neutral, as well as the grounding conductor.

For master electricians, it couldn't be easier. But a beginner needs to know the theory before starting practice. First you need to understand the questions:

• What is the difference between phase and zero?
• Why is grounding needed?

So, an energy network is a system where all the wires are distributed between phases, of which there are only three. A priori, the voltage between phases flows in a straight line. Here it is equal to 380 volts.

It is logical that we ask the question: why is the voltage on the sockets 140 units less? The whole problem lies in the potential difference between the neutral wire and one of the phases. In other words, this is the main difference between linear voltage and the one we are used to, which is known among craftsmen as phase voltage.

Features of the electrical network in everyday life

Before electricity is distributed throughout the building, line voltage is supplied to it. Already in apartments the wiring is connected to one of the phases and to the neutral conductor. Thus, the voltage supplied to the consumer is reduced.

Please note that when correct installation For household wiring, grounding is mandatory. There are buildings in which there may be no grounding conductors. These are often very old buildings. Before you begin, you need to figure out what each cable is for.

Necessary equipment

You are ready to get down to business, but don’t rush and be sure to read the instructions on how to determine phase and zero. Care should be taken in advance to ensure that the instruments used to take measurements (indicator screwdriver or tester, multimeter) are ready for use.

Collect for yourself a set that you will use to process the wiring. It can accommodate all kinds of knives, pliers, pliers, and so on. You may need a good marker to help you make marks along the way.

Using the Tester

The tester is a tool that is essentially a screwdriver with an LED. It is called an indicator and is used if you don’t have a regular screwdriver at hand. Below is an algorithm for determining phase and zero using an indicator screwdriver.

• Use your thumb and middle finger to pinch the device.
• From the end of the handle, place your index finger on a special metal circle.
• Use the metal side to touch the ends of the cable that have been stripped of insulation.
• The LED will light up if the wire you touched contains a phase.

Remember to follow safety precautions when working with electricity. Especially if you use an indicator.

• Firstly, when doing the test, do not touch the metal part of the device under any circumstances.
• Secondly, in order to avoid breakdown of the insulation, prepare the device, clean it of anything that can stick to it.
• Thirdly, there are situations when you need to be sure there is no voltage. Therefore, you should check whether the device works.

Using a Multimeter

The device that measures voltage is called a multimeter. It comes in two types: pointer and digital. We will describe below how to determine phase and zero with a multimeter.

Before starting measurements, set up the device. Set the AC current measurement limits (sign “~V” or “ACV”). Determine the value that will exceed 250 V (when using digital devices, 600, 750 or 1000 V are most often set). At the same moment, the probes of the device should touch the conductors. This way you will determine the voltage that is on at the moment in stock.

It is interesting to know that there are techniques, knowledge of which will help you figure out where the phase is and where it is not without the use of technology.

The most common is the visual method. In some cases, a test lamp is used, which should operate on 220 V and not be too powerful. We will describe the use of these methods in more detail below.

Visual method

For an experienced electrician, it will not be difficult to understand the wiring just by looking at it. But it remains unclear to a beginner: how to determine the phase by the color of the wires? To do this, just learn the standard and remember:

• the phase corresponds to white, brown, red, pink, purple, orange, turquoise and black;
• the neutral wire was marked with blue or cyan shades;
• For grounding, only khaki or yellow-green tones were always used.

If you are not sure that the connection is made in accordance with standards and regulations, or the wiring in your home has insulation of one color, it is important to have an indicator and use it every time you finish one stage and start another.

Using the lamp

To use a test lamp, you need to touch the wire whose phase you are determining with one probe, and the ground with the other. The wire that will become the light source in the lamp will contain the phase. In this case, it is important to know what to do if the wiring has 2 phases and there is no grounding.

Sometimes it is played by metal pipes through which the water is supplied. cold water or heating. It is important to clean in advance the areas that the probe will touch.

Visual inspection algorithm

First, open the shield. Take a good look circuit breakers, the number of which depends on design load. There are 2 connection options for the machines:

• the wire contains only a phase;
• both phase and zero.

The ground wire is connected directly to the busbar.

Now that you know the meaning of the colors and the location of the cables, all that remains is to check that everything in the panel complies with the standard.

Next, provided that your wire insulation in the panel complies with the rules, you need to open each junction box and visually examine the condition of the twists. There should be no inaccuracies here either.

Very often there are moments that you should not focus on. For example:.

• The distribution box contains a switch connected to the phase.
• The installers used wires with two cores, the insulation of which differed from the standard.

It is important to remember: even if the electrician followed all the rules and regulations when making the wiring, and the insulation of each cable complies with the standards, still check the phase wire using an indicator screwdriver.

Be sure to adhere to safety regulations and be careful and extremely attentive when solving electrical problems yourself.

Anyone who has any knowledge of electrical engineering is familiar with many terms and definitions. And even more so for professional electricians. But most of the residents do not know what zero and phase are. What do these words mean? How to determine where and what is? In this article we will try to clarify.

General information

In our everyday life We encounter electricity almost everywhere we go. Be it work or various institutions: cinema, theater, shops, sports complexes - the list could take a very long time. Needless to say, we use many electrical appliances every day, and 20 or 30 years ago there were not as many of them as there are now. Moreover, their number is growing with enviable frequency.

But all electrical equipment cannot work forever and sooner or later it begins to break down, which is simply inevitable. Perpetual motion machine No one has invented it yet, so you shouldn’t hope for a miracle. Some people want to learn something new, unknown, and electricity is no exception. If only because you can carry out repairs yourself household appliances. Of course, it is better to invite a specialist, but light work you can do it yourself. Only for this it is necessary to study fundamental concepts in order to understand what zero and phase are.

What is electricity?

The description of current should begin with the concept of electric charge, which, in fact, is a scalar quantity. If you take an ebonite stick and rub it on wool, it will develop a negative charge. This is due to the excess electrons resulting from contact with the wool. This is called static electricity and occurs in the hair. Only in this case the charge is positive because electrons are lost.

As for electric current, it is the ordered movement of charged particles along some conductor. This movement occurs due to the electromagnetic field. Current can be of two types:

• Constant - its meaning and direction do not change.
• Variable - it is already changing over time.

Phase

The terms “phase”, “zero” and “ground” themselves are well known to professional electricians. But, for example, the phase is also found in physics - under this definition several states of water can be called:

• liquid;
• hard;
• gaseous.

In addition, phase can be understood as several stages of oscillation, which can refer to wave motion. In astronomy, this has a slightly different meaning, which can be understood by observing the moon.

A little higher we discussed how electricity is generated at stations. So it is the working phase, which electricians simply call the phase, that is supplied with voltage. To more accurately imagine what this means, we should expand on the following concept - zero.

Zero

As you know, sockets have two holes, so plugs have two pins. This usually occurs in old houses, where only two wires, zero and phase, are suitable for each consumer.

In European countries and recently in Russia, the European standard has begun to be used. Here, instead of two cores or wires, there are already three, due to the inclusion of an additional protective conductor.

But what is zero and is it needed at all? The answer is clear: you need it! To arise electric current and began to power some household appliance (hair dryer, kettle, iron, etc.), a closed circuit is required. This is provided by zero and phase. That is, electricity enters our homes through the phase wire, passes through the consumer (work is done) and returns back through the neutral conductor.

In this case, it is important that the connected device works - the machine washes, the TV shows, the iron and kettle warm up, etc. Otherwise, the current will not flow, but the voltage in the phase will not go anywhere. Therefore, it is important to ensure that children do not insert anything into the socket.

Earth

It is important not only to know how to determine phase and zero, you also need to distinguish between grounding, which has become used in new buildings. As we now know, there is no electricity without phase and zero, that is, it flows between these two wires. It’s just worth clarifying what it is alternating voltage. In Russia and a number of countries, the power grid is characterized by a frequency of 50 Hz (hertz). This means that the current changes its direction from phase to zero and vice versa very often - 50 times per second!

If voltage passes through the phase, then the neutral conductor does not have it. Since most of the houses on the territory Russian Federation was built back in the days of the USSR, then in the input electrical panel the neutral wire is connected to the “ground” and additionally to a ground electrode, which is dug into the ground. In this case, the “ground” is directly connected to the body of the shield, and the zero is located in an insulated block.

Methods for determining phase and zero

It is not enough to understand what zero and phase are; in no case should they be confused! If this does not matter when switching on, then when installing the wiring, especially yourself, this must be taken into account. Otherwise, you can create a short circuit in the circuit. Therefore, you need to clearly understand where the phase is and where the zero is.

If you need to replace a switch socket or chandelier, the first step is to determine where exactly the neutral and phase are located. For a trained person this will not cause any problems, but for most people this is a serious task.

But don’t despair, finding these wires is not as difficult as it might seem at first glance. There are several methods that will be discussed below.

Color orientation

This is the safest way to determine the phase and neutral wires. You need to know what colors they are designated by, and to avoid any confusion, the following colors of the zero and ground phases have been introduced:

• Blue either blue-white color- this is a working zero.
• The color yellow-green usually denotes a protective zero.
• Red, white, black, brown phase conductors are painted.

Each country has its own phase color. It’s worth noting that this method is only suitable for new buildings whose wiring is designed in accordance with the IEC 60446 standard, adopted in 2004. Determine phase and zero according to color coding in old houses, such as Khrushchev, Stalin, Brezhnev, it is impossible. In this case, another method may be suitable.

Indicator screwdriver to help

An indicator screwdriver is an essential tool in the kit of every home handyman. Using this universal tool, you can not only unscrew fasteners, but also find the phase.

The procedure is very easy, since no special knowledge or skills are required. All you need is:

• Touch the metal end bare wire or one of the channels in the outlet.
• During testing, do not touch the working part itself under any circumstances!
• You need to touch the contact pad of the tool with your thumb (or any other finger).

This method, as well as determining the phase and zero by the color of the wires, works flawlessly.

If voltage is present, the screwdriver indicator will light up, otherwise it is not a phase, but a zero. In addition to the light bulb, the screwdriver contains a resistor, which creates resistance to the flow of current and reduces the voltage slightly. Therefore, the check will be completely safe.

Determining phase with a multimeter

Another equally well-known device among radio amateurs is a multimeter, which can also be used to find the phase in a home electrical network. On the device, the alternating current measurement mode is selected (usually designated V~) and the limit is set to more than 220 V. Usually this is 500, 700 or 800 Volts. The probes must be connected to the COM (black) and VΩmA (red) connectors.

One probe (usually red) needs to touch the bare section of the wire or immerse it in some channel of the socket. With another (black) probe we touch some grounded surface (heating radiator, steel wall elements, etc.). Moreover, if the red probe is in phase, then the device display will show a voltage value in the range from 100 to 230 V, provided that there are no power outages. Otherwise it will be zero.

Phase-zero loop

It is worth periodically measuring the phase-to-zero resistance, which will allow electrical appliances to operate uninterruptedly. The main reason for such measurements is the frequent operation of the machines. This is usually due to overloads in the electrical network or the presence of a short circuit. All this negatively affects the operation of household appliances.

Not everyone understands what a phase and zero loop means. This designates the circuit that is formed by connecting the neutral wire located in the grounded neutral. This is how a loop is formed.

In conclusion

You can find many ways to find phase and zero without special equipment. For example, “craftsmen” use raw potatoes or tap water. However, it is highly not recommended to conduct such experiments, since there is a great risk to one’s own health.

There are proven methods that do not pose a threat if safety precautions are followed. Therefore, there is no need to reinvent the wheel and come up with who knows what.