The indicator lights up phase or zero. Determination of phase and zero: an overview of methods

Anyone who is at least to some extent versed in electrical engineering is familiar with many terms and definitions. And professional electricians even more so. 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 there? Within the framework of this article, we will try to clarify.

General information

In our daily life, we encounter electricity almost anywhere we are. Whether it is work or various institutions: cinema, theater, shops, sports complexes - you can list for a very long time. Needless to say, we use many electrical appliances every day, and 20 or 30 years ago there were not so many of them as now. Moreover, their number is growing at an enviable frequency.

But all electrical equipment cannot work forever and sooner or later it starts to break down, which is simply inevitable. Nobody has invented a perpetual motion machine yet, so there is no need to hope for a miracle. Some people want to learn something new, unknown and electricity is no exception. If only because you can independently repair household appliances. Of course, it is better to invite a specialist, but easy work you can do it yourself. Only for this it is necessary to study the fundamental concepts in order to understand what zero and phase are.

What is electricity?

The description of current should start with the concept of electric charge, which is, in fact, a scalar quantity. If you take an ebony stick and rub it against wool, then it will have a negative charge. This is due to the excess of electrons resulting from contact with the fur. This is called static electricity and it happens on the hair. Only in this case, the charge is positive, since electrons are lost.

As for the electric current, this is the ordered movement of charged particles along some conductor. This movement arises from the electromagnetic field. The current can be of two types:

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

Phase

As such, the terms "phase", "zero" and "ground" are familiar to professional electricians. But, for example, the phase is also found in physics - under this definition, several states of water can be called:

• liquid;
• solid;
• gaseous.

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

A little above, it was considered how electricity is born at stations. So it is to the working phase, which electricians simply call - the phase, that voltage is applied. In order to more accurately imagine what this means, the following concept should be disclosed - zero.

Zero

As you know, sockets have two holes, respectively, the plugs have two pins. Usually this is found in old houses, where only two zero wires, a phase, are suitable for each consumer.

In European countries and more recently on the territory of Russia, the European standard has been applied. 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 unequivocal: it is necessary! In order for an electric current to arise and begin to power some household appliance (hairdryer, kettle, iron, and so on), a closed circuit is needed. This is provided by zero and phase. That is, through the phase wire, electricity enters our houses, passes through the consumer (work is done) and returns back through the zero conductor.

In this case, it is important that the connected device works - the machine washes it, the TV is shown, the iron and the kettle are warming up, etc. Otherwise, the current will not flow, but the voltage on the phase will not go anywhere. Therefore, it is important to ensure that babies do not plug anything into the outlet.

Earth

It is important not only to know how to determine the phase and zero, it is also necessary to distinguish the grounding, which has become used in new buildings. As is now known, without phase and zero there is no electricity, that is, it flows between these two wires. It is only worth clarifying what an alternating voltage is. 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 lead-in electrical panel the zero wire is connected to the "ground" and additionally to the 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.

Phase and Zero Determination Methods

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

If it is necessary to replace the switch socket or chandelier, the first step is to determine exactly where the zero with the phase is located. For a trained person, this will not cause any problems, but for most people it is a serious task.

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

Color orientation

This is the most safe way by definition of phase and neutral wires. You need to know what colors they are indicated, and so that there is no confusion, the following colors of the zero and earth phases have been introduced:

• Blue or blue-white color is a working zero.
• It is customary to denote a protective zero in yellow-green color.
• Red, white, black brown phase conductors are painted.

Each country has its own phase color. It should only be noted that this method is only suitable for new buildings, whose wiring is designed in accordance with the IEC 60446 standard, adopted in 2004. It is impossible to determine the phase and zero according to the color marking in old houses, such as Khrushchev, Stalinka, Brezhnevka. In this case, another method may work.

Indicator screwdriver to help

The indicator screwdriver is an essential tool in every kit home master for all trades. With this universal tool, you can not only unscrew the fasteners, but also find the phase.

The procedure is very easy, since special knowledge and skills are not required here. All you need is:

• With the metal end, touch a bare wire or one of the channels in the outlet.
• During the check, do not touch the working part itself!
• You need to touch your thumb (or any other) to the contact pad of the tool.

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 zero. In addition to the light bulb, the screwdriver has a resistor, which creates resistance to the flow of current and the voltage decreases slightly. Therefore, the check will be completely safe.

Phase detection with a multimeter

Another device, no less well-known among radio amateurs, is a multimeter, which can also be used to find the phase in a home electrical network. The device selects the alternating current measurement mode (as a rule, it is indicated by V ~) and the redistribution is set to more than 220 V. Usually this is 500, 700 or 800 Volts. Probes must be connected to COM (black) and VΩmA (red) connectors.

With one probe (usually red), you need to touch the bare section of the wire or immerse it in some channel of the socket. With another (already black) probe, we touch some grounded surface (heating battery, steel wall elements, etc.). In this case, if the red probe is on a phase, then the display of the device 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

Periodically, it is worthwhile to measure the phase-zero resistance, which will allow electrical appliances to operate in an uninterrupted mode. The main reason for such measurements is the frequent triggering of machines. This is usually due to overloads in the power grid or short circuits. All this negatively affects the operation of household appliances.

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

Finally

There are many ways to find phase and zero without special equipment. For example, "craftsmen" use raw potatoes or tap water. However, it is highly discouraged to conduct such experiments, since there is a great risk to your own health.

There are proven methods that do not pose a threat when observing safety precautions. Therefore, you should not reinvent the wheel and invent something.

The need to figure out where the phase wire is located, and where the zero one can arise for any owner of a house or apartment. This is sometimes necessary when carrying out the simplest electrical work, for example, installing switches and sockets, replacing lamps. It happens this is important when diagnosing faults in the home electrical network, performing preventive or repair measures. And some devices, for example, thermostats, when connected to the power supply require strict adherence to the location of the "L" and "N" wires in the terminal block. Otherwise, nothing guarantees either their durability or correctness in work.

This means that it is necessary to learn how to independently determine the phase and neutral wire. This is not so difficult - there are proven techniques using simple and inexpensive devices. But some users, for some unknown reason, ask the question in search engines: how to determine the phase and zero without devices? Well, let's discuss this problem.

A few words about the device of the home electrical network

In the overwhelming majority of cases, apartments use a single-phase 220 V / 50 Hz power supply. A three-phase powerful line is supplied to a multi-storey building, but then switching to consumers (apartment) is carried out in distribution boards on one phase and a zero wire. They try to perform the distribution as evenly as possible so that the load on each of the phases is approximately the same, without strong distortions.

In houses of modern construction, the laying of protective grounding loops is also practiced - modern powerful household appliances for the most part require such a connection to ensure operational safety. Thus, three wires are suitable for sockets or, for example, many lighting fixtures - phase L(from English Lead), zero N(Null) and protective earth PE(Protective Earth).

In old buildings, there is often no grounding protective circuit. This means that the internal wiring is limited to only two wires - zero and phase. It is simpler, but the level of safety in the operation of electrical devices is not up to par. Therefore, when carrying out major overhauls of the housing stock, measures to improve the internal power grids are often included - the PE circuit is added.

In private houses, the input of a three-phase line can also be practiced. And even some points of consumption are often organized with the supply of a three-phase voltage of 380 volts. For example, it can be a heating boiler or a powerful technological machine tool in a home workshop. But the internal "household" network is still made single-phase - just three phases are evenly distributed along different lines to avoid skewing. And in any ordinary outlet, we will still see the same three wires - phase, zero and ground.

By the way, in this case it is said unambiguously about grounding. And this is for the reason that the owner of a private house is not connected by anything and is simply obliged to organize it, if there was no such circuit, say, when purchasing a previously built building.

Grounding in a private house - how can you do it yourself?

Having a protective ground loop in your residential domain means significantly increasing the level of safety in the operation of electrical appliances. And by and large - and in general the degree of safety of living in the house for the whole family. If it is not yet there, then, without delaying for a long time, it is necessary to organize. To help - the article of our portal, to which the recommended link leads.

Are there in principle ways to determine the phase and zero without instruments?

First of all, let's immediately "take the bull by the horns" and answer this important question.

This method is presented in singular , and even then, to a certain extent, it can be considered conditional. We are talking about the color marking of the wires of the laid power cables and wires.

Indeed, there is an international standard IEC 60446-2004, which must be adhered to by both cable manufacturers and electrical installation specialists.

Since we are talking about a single-phase network, then everything should be simple here. The insulation of the working zero conductor should be blue or light blue. Protective grounding is most often characterized by a green-yellow striped color. And the insulation of the phase wire - in some other color, for example, brown, as shown in the illustration.

It should be correctly understood that Brown color for a phase it is not at all a dogma. Other colors are very common - in a wide range from white to black. But in any case, it will differ from both the neutral wire and the protective ground.

It would seem that everything is very simple and clear. You can't go wrong. So why is this the only way to recognize wires without devices is still considered conditional?

The point is that, alas, not everywhere and not always adhere to such a color "pinout". There is no need to talk about old houses. There, the wiring is mainly made with wires in exactly the same white insulation, of course, that does not tell anyone anything.

And even in the case when cables with wires in insulation of different colors are laid, you need to be absolutely sure that the specialists conducting the electrical work strictly followed the rules. Often called "masters", invited from outside, take liberties in these matters. This means that you can be sure if the work was supervised, carried out by a truly professional electrician with an impeccable reputation. Or if, during the operation, the owners already had the opportunity to make sure that the "color scheme" was observed. And, finally, if the landlord carried out the entire installation on his own, strictly following the recommended standard.

In addition, it happens that it is used for wiring, the color of the insulation of the conductors of which is very far from the standard "set" - blue, green-yellow and phase of any other shade. If there is no diagram with a description, then the color of the wires will not say anything definite in this situation.

This means that you will have to look for the phase and zero in other ways, using instruments.

If the reader is now waiting for explanations about other methods of determining zero and phase, with the help of some "exotic" devices like raw potatoes, then it is completely in vain. The author of the article and himself never I did not indulge in such methods, and other will never, under any circumstances recommend.

We will not even touch upon the reliability of such checks. This is not the main point. Such "experiments" are extremely dangerous. Especially for a person inexperienced in electrical engineering. (And an experienced one, believe me, it is always better to use a truly reliable and safe technique). In addition, such manipulations can be seen by young children. Wouldn't it be alarming later, knowing about the baby's inherent desire to imitate their parents in many ways?

And, by and large, it will hardly be possible to imagine a situation in which the circumstances are so hot that you have to resort to such "pagan" methods? Is it difficult to go to the nearest store and buy a simple indicator screwdriver for 30 ÷ 35 rubles and forget about the problem? If it is evening, then there is no way to endure until the morning with the diagnosis? Yes, after all, you can't ask your neighbor for an indicator for a few minutes?

By the way, potatoes are something else ... There are "experts" who in all seriousness recommend checking the presence of a phase with a light touch of a finger to the conductor. Like, if in a dry room, but in shoes with dielectric soles, then nothing terrible will happen. I would like to ask such "advisers" - are they sure that all those who have heeded their recommendations are safe and sound? What did the "emergency" not happen when a person trying the phase "by touch" accidentally touched a grounded object or other bare conductor with his body?

To understand the degree of danger of such "checks", we recommend that you familiarize yourself with the information about what threats this "harmless" electric current in the 220 volt network poses to life and health. Perhaps after that, many questions will be removed by themselves.

"Household" alternating voltage of 220 volts can be fatal!

The life of a modern person cannot be imagined without electricity. But it does not always act only as a “friend and helper”. With neglect of the rules of operation of devices, with negligence, carelessness, and even more so - an obviously disregard for compliance with safety requirements, it can punish instantly and extremely cruelly. For the human body, a separate publication of our portal tells in detail.

And therefore - we will summarize. There are no ways, except for one mentioned, to independently get ahead of the location of zero and phase without instruments - does not exist.

Now let's go through the possible methods of such a check.

Determination of phase and zero in different ways

Using an indicator screwdriver

This is perhaps the simplest and most accessible technique. As already mentioned, the cost of the simplest device is very low. And learning to work with him is a matter of a few minutes.

So, how does a conventional indicator screwdriver work:

All the "stuffing" of this probe is assembled in a hollow case (item 1) made of dielectric material.

The working body of such a screwdriver is a metal tip (item 2), most often of a flat shape. To reduce the likelihood of accidental contact with other conductive parts near the wire under test, the exposed tip is usually small. The sting go short by itself, go "put on" in an insulating sheath.

Important - the tip of the indicator screwdriver should be considered exactly as a contact tip during testing. Yes, if necessary, they can perform the simplest installation operations, for example, unscrew the screw holding the cover of the socket or switch. But regularly using it as a screwdriver is a big mistake. And for a long time with such operation, the device will not live 0, it simply is not designed for high loads.

The metal rod of the tip entering the housing becomes a conductor that makes contact with the internal indicator circuit. And the circuit itself consists, firstly, of a powerful resistor (item 4) with a nominal value of at least 500 kOhm. Its task is to reduce the current strength indicators when the circuit is closed to values ​​that are safe for humans.

The next element is a neon lamp (pos. 5), which can light up at very low rates of current flowing through it. Mutual electrical contact of all circuit elements is provided by the holding spring (pos. 6). And it, in turn, is compressed by a plug screwed into the end end of the body (item 7), which can be either completely metal or having a metal "heel". That is, this plug plays the role of a contact pad during checks.

By touching the contact pad with a finger, the user is "included" in the circuit. The human body, firstly, itself has a certain conductivity, and secondly, it is a very large "capacitor".

This is the basis of the principle of searching for phase and zero. The tip of the indicator screwdriver touches the stripped conductor (terminals of the socket or switch, other thin-bearing part, for example, the contact tab of the bulb holder). Then touch the probe pad with your finger.

If the tip of the screwdriver touches the phase, then when the circuit is closed, the voltage is sufficient to cause a current that is harmless to humans, leading to the glow of a neon lamp.

In the same case, if the check fell on the zero contact, the glow will not occur. Yes, there is also a small potential there, especially if other electrical appliances are working in the apartment (house) at this time. But the current due to the resistor will be so small that it should not cause the indicator to glow.

Likewise, on the grounding conductor - there, in fact, there should not be any potential at all.

In the same case, if, say, two contacts in the outlet show a phase, this is a reason to look for the cause of such a serious malfunction. But this is already a topic for separate consideration.

The test is carried out in a slightly different way with an indicator screwdriver of a more advanced type. Such probes allow not only determining the phase and zero, but also conducting continuity tests and a number of other operations.

Outwardly, such indicator screwdrivers are very similar to the simplest ones discussed above. The only difference is that an LED is used instead of a neon light bulb. And in the case there are 3 volt batteries, which ensure the functioning of the circuit.

If you are not sure which specific screwdriver is available to the user, a simple test can be performed. They just touch both the tip and the contact pad at the same time. In this case, the circuit will close, and the LED will signal this with its glow.

What is it all said for? Yes, simply because the algorithm for determining the phase and zero when using such a screwdriver changes somewhat. Specifically, you do not need to touch the contact pad. A simple touch of the phase conductor will cause the indicator to light. There will be no such glow at the working zero and on the ground.

Nowadays, more expensive indicator screwdrivers with electronic filling, light and sound indication are widely presented on sale. And often - even with a digital liquid crystal display showing the voltage on the tested conductor. That is, in fact, the indicator screwdriver becomes a simplified semblance

Using these is also not particularly difficult. You will have to be guided by the instructions attached to the device - in any case, the device must unambiguously indicate the presence of voltage on the phase wire and the absence - on zero or ground. The main thing is to make sure, before starting the check, that the capabilities of the device used correspond to the voltage in the network. This is usually indicated directly on the indicator housing.

Another "relative" of indicator screwdrivers is the non-contact voltage probe. There are no conductive parts at all on its body. And the working part is an elongated plastic "nose", which is just brought to the tested conductor (terminal).

The convenience of such a device also lies in the fact that it is not at all necessary to strip the tested wire from insulation. The device reacts not to contact, but to the electromagnetic alternating field created by the conductor. At a certain tension, a circuit is triggered, and the device signals that there is a phase wire in front of us by turning on a light and sound signal.

Determining phase and zero using a multimeter

Another control and measuring device that any skilled home owner would need to acquire is the cost of inexpensive, but sufficiently functional models - within 300 ÷ 500 rubles. And it is quite possible to make such an acquisition once - it will certainly be in demand.

So, how to determine the phase with a multimeter. There may be various options here.

BUT. If the wiring includes three wires, that is, phase, zero and protective earth, but with color coding or there is no clarity, or there is no confidence in its reliability, then the exclusion method can be applied.

This is done as follows:

• The multimeter is getting ready for work. The black test lead is connected to the COM connector, the red one - to the voltage measurement connector.
• The operating mode switch is transferred to the sector dedicated to measuring alternating voltage (~ V or ACV), and the arrow is set to a value that exceeds the voltage in the network. IN different models this could be, for example, 500, 600 or 750 volts.

• Further, the voltage is measured between the previously stripped conductors. There may be three combinations in this case:

1. Between phase and zero, the voltage should be close to the nominal 220 volts.
2. There may be the same picture between phase and ground. But, however, if the line is equipped with a current leakage protection system (residual current device - RCD), then the protection may well work in this case. If there is no RCD, or the leakage current is quite insignificant, then the voltage, again, is in the nominal area.
3. There should be no voltage between zero and ground.

That's just last option will show that the wire that does not take part in this measurement is phase.

After checking, it is necessary to turn off the voltage, insulate the stripped ends of the wires and mark. For example, by sticking strips of white adhesive plaster and making the appropriate inscriptions on them.

B. You can check the wire (contact in the socket) and a direct example of the voltage on it. This is done like this:

• Preparing the multimeter for work - in the same way as shown above.
• Further, a control voltage measurement is carried out. Two goals are pursued here at once. First, you need to make sure that there is no break in the line, and we will not look for phase and zero, as they say, from scratch. And secondly, the device itself is tested. If the readings are correct, it means that the switching is done correctly, and a powerful resistor is included in the circuit, which will ensure the proper level of safety for subsequent operations.
• Touch the tested conductor with the red test lead. If this is a socket, then a probe is inserted into the socket, if the stripped end of the conductor is better, it is better to use a "crocodile" clip.
• The second probe is touched with the finger of the right hand. And - observe the readings on the display of the multimeter.

- If the test probe was set to zero, the voltage will not be displayed. Or its value will be extremely small - measured in units of volts.

- In the same case, when the control wire is in phase, the indicator will show a voltage of several tens, or even more volts. The specific meaning is not so important - it depends on the very a large number factors. This is the established measurement limit of the used multitester model, and the features of the resistance of the body of a particular person, and humidity, and air temperature, and the shoes in which the master is shod, etc. The main thing is that there is tension, and it is strikingly different from the second contact. That is, the phase has been found.

Probably, not everyone will be able to overcome the psychological boundary - touch the probe with your hand when the multitester is connected to the outlet. There is nothing special to be afraid of - we pre-tested the device by measuring the voltage. And the current flowing through it now when the circuit is closed is not much different from what passes through the indicator screwdriver. But nevertheless - for some, such a touch becomes ecologically impossible.

It's okay, you can do it a little differently. For example, just touch the second probe to the wall - plaster or even wallpaper. There is still some moisture, and this will close the circuit. True, the readings on the indicator will most likely be much less. But even these will be enough to unambiguously figure out which of the contacts is phase.

Such a check will be no worse if any grounded device or object, for example, a heating radiator or water pipe... Will fit and metal carcass that does not even have grounding. And sometimes even one probe connected to the outlet with the second one just lying on the floor or on the table, allows you to see the difference. When testing the phase, the tester can show units or a couple of tens of volts. With a zero conductor, of course, there will be zero.

IN. As you can see, there are no special problems with determining the phase. But what if there are three wires. That is, we have decided on the phase, and now we need to find out which of the remaining two is zero, and which is protective ground.

But this is not so simple. There are, of course, several methods available. But none of them can claim to be "the ultimate truth." That is, special devices are required here, which are at the disposal of professional electricians.

But sometimes self-testing helps too.

One of them has already been mentioned above. When the voltage is measured between phase and zero, this should not cause any peculiarities. But when measuring between phase and ground, due to the inevitable leakage of current, the protection system - RCD may be triggered.

Another way to detect zero and protective ground is ringing. That is, you can try by switching the multimeter to measure resistance in the range, say, up to 200 Ohm and, without fail - by turning off the voltage on the shield, alternately measure the resistance between these conductors and a guaranteed grounded object. On the PE conductor, this resistance, in theory, should be much lower.

But, again, this method does not differ in reliability, since the connections are practiced differently, and the meanings can turn out to be approximately the same, that is, they do not say anything.

Another option is to disconnect the grounding bus from the loop leading to it. Or remove from it the alleged wire to be checked. Then - either make a ringing out, or take an alternate measurement of the voltage between the phase and the remaining two conductors. The results often make it possible to judge where is zero and where is PE.

But to tell you the truth, this method does not seem to be either effective or safe. Again, due to the various nuances of wiring and switching on switchboards, the result may not be entirely reliable.

Find out, as well as familiarize yourself with its purpose and methods of working with a video device, from our new article on our portal.

So if you need guaranteed clarity, where is zero and where is the grounding, and it is not possible to find out yourself, it is better to contact a qualified electrician. With all the similarity of these conductors in home wiring, they should not be confused in any case.

So, the main available methods for determining the phase and zero were considered. We emphasize once again - if the visual method of determination (by color marking of the insulation) does not guarantee the reliability of the information, then all the rest should be carried out exclusively using special devices. No "100% technique" with all kinds of potatoes, plastic bottles, cans of water and other "toys" are completely unacceptable!

By the way, the publication does not say anything about the use of the so-called "control" - a light bulb in a socket with two conductors. Again, this is because such testing is directly prohibited by the current rules for the safe operation of electrical installations. Do not risk yourself and do not pose a potential threat to your loved ones!

At the end of the publication - a short video clip dedicated to the problem of finding a phase and zero.

Video: How you can determine the location of the phase and zero

When repairing electrical wiring, as well as installing an outlet and a switch, it is often necessary to determine the phase and zero. For professional electricians, this is an easy task. But how to cope with this task for those who are new to the device of power grids? The article will help you deal with this task.

First you need to understand what the household electrical network consists of. It usually consists of a three-piece wire:

1. Phase;
2. Zero;
3. Grounding.

The simplest case of an electrical circuit is a single phase circuit. There are only two wires in this circuit - phase and zero. Through the first wire, electric current flows to the consumer (all household appliances are the current consumer). The second wire is designed to return the electric current back. In the single-phase network under consideration, there is another wiring: it is called ground or ground. This wire does not conduct electric current, but acts as a fuse, that is, in the event of a break, it prevents electric shock. With the help of this wire, excess electricity goes into the ground, that is, it is grounded. A phase is a conductor through which an electric current flows to a consumer.

Unlike other conductors, only phase has a voltage of 220 V... But for the use of electricity, one phase alone is not enough. Zero wire is a conductor stretched from the generator of the power plant to the consumer. Despite the fact that it practically does not conduct electric current, it is a full participant in the transmission of current through metal wires. Grounding is a conductor connected to ground and designed to isolate a phase during a breakdown, in order to protect a person from electric shock. To determine phase and zero there are three options:

1. Determination of phase and zero visually, that is, without devices;
2. Determination of phase and zero using an indicator screwdriver;
3. Determination of phase and zero by means of a multimeter.

Do not forget that when carrying out electrical work, the machines must be turned off. In addition, make sure that the handles are properly grounded. Otherwise, their use poses a threat to human health.

How to determine the phase and zero without instruments?

The visual method for phase and zero detection is the simplest, because its implementation does not require any instruments and equipment. If the electrical wiring is made according to the standard, then the determination of the phase, neutral and grounding conductors is carried out by color-coded wires:

Knowing which color corresponds to which wire, you can easily determine what the wire is intended for. This method turns out to be advantageous in many cases, with the exception of wires that are used in switches and switches, since in these electrical equipment a different scheme is applied... Sometimes the color coding of the wires does not correspond to the standard. This is possible in cases where the electrical equipment uses old wiring or electricians installed non-standard wires with a different marking. Then you can use more practical methods for detecting phase and zero.

How to determine the phase and zero with an indicator screwdriver?

One of the most common methods for detecting zero and phase is considered to be the method consisting in the use of an indicator screwdriver. The body of this device is equipped with a resistor and an LED. A metal tip of the tool is connected to the resistor, which acts as a conductor. A resistor is needed to reduce the current to the maximum possible value. This ensures safe use of the tool. The current flows through the probe and resistor of the instrument and is reduced to values ​​that do not pose a threat to human life. This is the whole principle of operation of this device.

The checking employee needs to touch the wires to be checked with the sharp end of the device in turn, touching the plate on the end of the device handle with his finger. After that, the circuit is closed and LED will be activated... The light of the LED indicates that the tested wiring is phase, and the other wiring is neutral. To detect phase and zero using an indicator screwdriver, the following algorithm is used:

How to determine the phase and zero with a multimeter?

Another popular method for detecting phase and zero is considered to be the method of using a multimeter. Measurement carried out in the following sequence:

When using a multimeter, you must compliance with the following rules:

• Do not use the multimeter in a damp environment.
• It is forbidden to change the position of the switch during measurement.
• Do not use a multimeter with defective test leads.

Phase wire color and zero

Many young electricians laugh at the colored wires. But time passes, and they respectfully recognize that this kind of marking helps to distinguish the phase from zero and ground at the right time. If the master incorrectly connected the wires by color, this can provoke an electric shock and short circuit. It is with the aim of the safety of people and premises that the wires have been selected in a peculiar color scheme.

According to the rules for the operation of installations, the grounding is colored yellow-green. It should be borne in mind that each manufacturer can apply yellow-green stripes in a different direction. And it also happens that the grounding comes across one color, either yellow or green.

Experienced workers know that zero has Blue colour in some cases it can be blue. Zero is a neutral working contact.

The individual color of the phase helps the electrician find the phase. Of course, there are quite a few color options, but still, manufacturers are more often used: brown, black or white.

Knowing the colors of all wires, finding zero and phase will not be difficult. But all the same, in matters related to electricity, it is better to consult a specialist.

During the repair, there are often cases when it becomes necessary 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, zero, as well as the grounding conductor.

For professional electricians, it's as easy as shelling pears. But a beginner needs to know the theory before starting practice. First you need to deal with the questions:

• what is the difference between the phase and zero?
• what is grounding for?

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

It is logical that we are asking the question: why the voltage at the sockets is 140 units less. The whole catch lies in the potential difference between the neutral wire and one of the phases. In other words, this is the main difference between the linear voltage and the usual to us, which is known among the masters as phase voltage.

Feature of the electrical network in everyday life

Before the electricity is distributed throughout the building, the voltage will be linear. Already in apartments, the wiring is connected to one of the phases and to the neutral conductor. Thus, the voltage that goes to the consumer is reduced.

Please note that when correct installation household wiring, grounding is mandatory. There are buildings in which the absence of grounding conductors is possible. These are often very old buildings. Before starting work, you need to find out what each cable is for.

Necessary accessories

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

Assemble for yourself a set with which you will handle the wiring. It can contain all kinds of knives, pliers, pliers, and so on. In the process, you may need a good marker to take notes.

Using the tester

A tester is a tool that is essentially a screwdriver with an LED. It is called an indicator and is used if you do not have an ordinary screwdriver at hand. Below is an algorithm for determining the phase and zero using an indicator screwdriver.

• Use your thumb and middle finger to pinch the device.
• From the side of the handle, place your index finger on a special metal circle.
• With the metal side, touch the stripped ends of the cable.
• 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 are using an indicator.

• First, when doing the check, do not touch the metal part of the device under any circumstances.
• Secondly, in order to avoid insulation breakdown, prepare the device, clean it from everything that can stick to it.
• Thirdly, there are situations when you need to be sure that there is no tension. Therefore, you should check if the device is working.

Using a multimeter

The device that measures the voltage is called a multimeter. It can be of two types: pointer and digital. How to determine the phase and zero with a multimeter, we will describe below.

Set up the device before starting measurements. Set the limits for measuring alternating current (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. Thus, you will determine the voltage that is currently available.

It is interesting to know that there are techniques, the knowledge of which will help to find out where the phase is and where it is not without using the technique.

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

Visual method

It will not be difficult for an experienced electrician to understand the wiring just by looking at it. But the beginner is not clear: how to determine the phase by the color of the wires? To do this, it is enough to learn the standard and remember:

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

If you are not sure that the connection is made according to the standards and norms, or the wiring in your house has insulation of a certain color, it is important to have an indicator in service and use it every time you finish one stage and start another.

Using the lamp

To use the test lamp, you need to touch one of its probes to the wire, the phase of which you determine, and the other to ground. The wire that will become the light source in the lamp and will contain the phase. It is important in this case to know what to do if the wiring has 2 phases, but there is no grounding.

In the role of it, pipes made of metal sometimes serve, through which cold water or heating is supplied. It is important to clean up in advance those places to which the probe will touch.

Visual inspection algorithm

First, open the flap. Consider carefully the circuit breakers, the number of which depends on the rated load. There are 2 connection options for the machines:

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

The ground wire connects directly to the bus.

Now that you know the meaning of the colors and the location of the cables, it remains only to check that everything in the shield corresponds to the standard.

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

Very often there are moments that you shouldn't focus on. For example:.

• The junction box contains a switch connected to a phase.
• The installers used wires with two conductors, the insulation of which was different from the standard.

It is important to remember: even if the electrician adhered to all the rules and regulations when doing 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 rules and be careful and extremely attentive when solving problems with electricity yourself.

When repairing electrical wiring, or servicing it, it may often be necessary to determine which wire is connected to zero and which to phase. This is required for installing switches or switching other electrical equipment. Before telling how to determine zero and phase, let's talk about the prejudices associated with this.

The most common misconceptions

Here are the common misconceptions associated with the definition of neutral and phase wires:

An example of such equipment is a controller that controls the operation of a gas boiler. When an “insufficient voltage” error is indicated, the polarity must be reversed.

A similar problem can occur on the pulse generator, as well as when connecting laboratory measuring equipment;

• if the cable has three cores, and one of them is multi-colored, then it is the ground. You can never be sure of this, especially considering what was the confusion with GOSTs in the last decade of the last century. Therefore, it is best to always check the cable.

Color coding

In order not to bother with the search for zero and phase in the future, it is necessary to adhere to a single standard prescribed in GOST R 50462-92.

The table shows what color this or that wire is indicated.

In older houses, wiring can be done with a single color wire. If you have a similar situation, we recommend marking the wiring leads with heat shrink tubing.

Don't trust the color coding if you have the slightest doubt. It is better to make sure once again that the assignment of the wires matches the colors.

The most affordable and common ways

The simplest method, which allows you to accurately determine the phase and neutral wire, is performed with an indicator screwdriver. You can buy it or assemble it yourself. The diagram of such a device is simple, it is shown in the figure below.

Designations on the diagram:

• A - contact plate;
• B - detector tip;
• R1 - resistance with a nominal value from 1.5 to 2 MΩ, power from 0.5 W;
• HG1 - any type of neon lamp.

Video instruction: determining phase and zero with an indicator screwdriver

The compact dimensions of the parts used make it possible to assemble the device in a ballpoint pen housing. Industrial designs resemble appearance a small screwdriver.

Determination of the connection of a wire to a phase or zero phase (in a two-wire circuit) is performed according to the step-by-step algorithm described below:

1. the wiring is de-energized;
2. a protective layer of insulation is removed from the wires to be tested (one centimeter will be enough);
3. we turn on the electricity, since it will not work to determine zero if the phase is disconnected;
4. with the tip of the probe, two wires are checked in turn, touching the contact plate of the indicator, as shown in the photo;
5. if the neon lamp lights up, the tested core is a phase of the electrical circuit.

In the socket, the voltage indicator works on two contacts

The situation when the probe detects two phases in the outlet and does not see zero can be confusing for a novice electrician. The matter becomes even more confusing if you measure the potential difference with a multimeter or tester. They will show that there is no voltage. These are characteristic signs of a zero break.

Note that with external signs of a lack of voltage in the wiring (according to the readings of the multimeter), you can get a rather noticeable electric shock. This is why the voltage probe should not be neglected.

To solve this problem, it is enough to eliminate the break in the neutral wire, if you do not know how to do this, it is better to entrust this work to professional electricians.

Methods for three-wire wiring

In this case, the third wire will be ground. The phase is easily found with a probe (how to do this was described above). To find zero and ground, you should use a multimeter or tester to determine them.

The procedure should be as follows:

1. using a probe, we determine the phase;
2. we measure the voltage between the phase and the remaining two wires;
3. the potential difference between zero and phase will be in the region of 220V, the voltage between ground and phase will be less than this value.

Actually, having a multimeter, you can determine the ground, zero and phase without a voltage indicator. We will tell you how to do this using the M820D model.

For this purpose, it is necessary to set the measuring range of the alternating current to more than 220V. The probes are connected to the V and COM sockets (shown in the photo below).

We measure the voltage between the three wires one by one, where there will be about 220V, one core is a phase, the second is zero. Accordingly, the third wire is ground.

Video: phase and zero determination with an indicator screwdriver and a multimeter (2 ways)

No instrumentation required

The household should have at least a voltage probe, but if there is none, do not worry, there are ways to determine the ground, zero and phase without instruments.

All you have to do is make a test lamp, something like the one shown in the photo. The lamp should work from 220V and not be too powerful (so as not to blind your eyes).

There are many options for implementing this device, the main thing is to provide reliable insulation in the places where the wires are attached to the lamp and probes. Naturally, if you need to test the wires in the box on the ceiling, you need to make the probes of the appropriate length.

To determine the phase, it is enough to connect one contact of such a probe to the tested wire, and the other to ground. The latter can be metal pipes heating or cold water. The place on the pipe to which you will touch the test lamp probe must first be cleaned.

The wire, when touched, the lamp will glow, and will be a phase.

A lot of videos have been published on the Internet on how to determine the phase without using any special equipment... For example, using raw potatoes or tap water. We want to warn you that the repetition of such dubious experiments can cause significant damage to your health.

We have described how to determine zero and phase, and to do it with maximum safety, so there is no need to invent new methods.