Phase testers. How to find phase and zero? Several ways to determine the phase and neutral wires. With the help of water

Any person doing electrical work at home or simply deciding to install a chandelier, sconce or connect an outlet will definitely come across the question - how to determine the phase, zero and ground at the wires at the installation site?

In our articles and instructions, we often post wiring diagrams, rules for installing and connecting electrical equipment to the network, and much more, where for correct execution of all operations, you need to know where the front phase wire, where is zero (working zero), and where is grounding (protective zero). For an experienced electrician, determining where the phase and zero or finding the ground is usually not difficult, but what about the rest?
Let's try to figure out how at home, without having complex specialized measuring instruments and electronic devices, to determine for yourself where the phase is, where is zero, and where is the ground in the wiring.
Of all known methods, the most simple definition phases and zero, we have selected the most, in our opinion, available in implementation and at the same time safe. For this reason, in the article you will not see tips - how to find the phase with the help of potatoes or calls for a short touch of the wires various parts body.
In fact, there are not so many options for determining the phase, zero or ground, for example, in a socket, without the use of specialized equipment, and sometimes, depending on your goals and objectives, it is enough just to know the color marking standard electrical wires adopted by us in order to distinguish them.
Wire marking by color
Really, the easiest way to determine the phase, zero and ground at electric wire, is to see the color coding and compare with the accepted standard. Each lived in modern wires used in electrical wiring, as well as electrical equipment has an individual color. Knowing which color of the cores corresponds to which function (phase, zero or ground), you can easily perform further installation.
Quite often, this is quite enough, especially in cases where the installation is carried out in new buildings or places with fairly new electrical wiring done by professional, competent electricians in all areas. modern rules and standards.
In our country, as in Europe as a whole, the IEC 60446 standard of 2004 is in force, which strictly regulates the color marking of electrical wires.
According to this standard for an apartment electrical network:
Working zero (neutral or zero) - Blue wire or blue-white
Protective Zero (earth or ground) - yellow-green wire
Phase – All other colors including black, white, brown, red, etc.

Now, knowing the wire color code standard, you can easily determine which wire performs which function. This applies to most cases, with the exception of wires suitable for switches, switches, etc., due to a fundamentally different scheme of operation of this electrical equipment.
If you are not sure about the exact correspondence of the colors of the wire cores to the IEC 60446 2004 standard, you have old wiring, you do not exclude the possibility of errors or even negligent attitude of electricians to their work, or maybe electricians laid wires of a different standard and, accordingly, a different color marking, then we proceed to practical method determination of phase and zero (working and protective).

HOW TO DEFINE THE PHASE, ZERO and GROUND AT THE WIRES YOURSELF

So let's start in order:

PHASE DETECTION

For greater convenience, it is always better to determine which of the available wires is the phase first.

PHASE DETERMINATION WITH INDICATOR SCREWDRIVER

The easiest way to find a phase wire is to search using indicator screwdriver. This the simplest tool anyone should have home master dealing with electrics in the apartment - whether it is a complete electrical installation, simple replacement lamps or installation of fixtures, sockets and switches.
The principle of operation of an indicator screwdriver is simple - when the tip of the screwdriver touches a live conductor and at the same time touches the contact, on the back of the screwdriver, with a finger, the indicator lamp in the tool body lights up, which signals the presence of voltage. Thus, you can easily find out which wire is phase.

The principle of operation of the indicator screwdriver is simple - inside the indicator screwdriver there is a lamp and resistance (resistor), when the circuit is closed (we touch the rear contact), the lamp lights up. Resistance protects us from electric shock, it reduces the current to a minimum, safe level.
This option for determining the phase on your own is the most preferable and we recommend using it, especially since the cost of an indicator screwdriver is more than affordable. The main disadvantage of this method is the likelihood of erroneous operation, when the indicator screwdriver, reacting to interference, determines the presence of voltage where it is not.

DETERMINATION OF PHASE, ZERO AND GROUND BY PILOT LAMP

Another way that you can determine the phase, neutral and ground wires in a modern three-wire electrical network is to use a test lamp. The method is ambiguous, but effective, requiring special care.
To begin the determination, it is first necessary to assemble the test lamp device itself. The easiest way is to use a cartridge with a lamp screwed into it, and fix the wires with the insulation removed at the ends in the terminals of the cartridge. If there is no electric cartridge at hand or there is no time to make something, you can use the usual table lamp with electric plug.

The technology for determining the phase, zeros and grounds using a test lamp is as simple as possible - connecting the lamp wires to the wires that need to be determined in turn, each with each.

Determine phase and zero from two wires

In case of definition control lamp phase wire among the two wires, you can only find out whether there is a phase or not, and which of the phase conductors cannot be determined. If, when connecting the wires of the control lamp to the conductors being determined, it lights up, then one of the wires is phase, and the second is most likely zero. If it does not light up, then most likely there is no phase among them, or there is no zero, which also cannot be ruled out.
In this way, rather, it is more convenient to check the operability of the wiring and the correctness of its installation. Determine the phase better indicator screwdriver, but the presence of zero can be recognized in this way.

In this case, you can determine the phase wire by connecting one of the ends coming from the control lamp to a known zero (for example, to the corresponding terminal in the electrical panel), then when the second end touches the phase conductor, the lamp will light up. The remaining wire, respectively, is zero.

Find phase, zero and ground from three wires:

In such a three-wire system, it is often possible to accurately determine the phase, neutral and ground wires with a test lamp.
We connect the contacts coming from the control lamp in turn to the cores of the cable that needs to be determined.
We act by elimination method:

We find the position in which the lamp is on, this will mean that one of the wires is phase and the other is zero.

Then we change the position of one of the contacts of the control lamp, then several options are possible:
- If the lamp does not light up (if there is an RCD or a differential circuit breaker of the line being tested, they can also work), then the remaining free wire is PHASE, and the tested ZERO and EARTH.

If, after changing the position, the lamp flashes for a short time, the RCD or differential will immediately work. the machine (if any), then the remaining free wire is ZERO, and the tested ones are PHASE and GROUND.
- If the line is not secured by the device protective shutdown(RCD) or differential automaton, and the light will be on in two positions. In this case, you can find out which wire is working zero (zero), and which is protective (grounding), you can simply turn it off in the metering and distribution panel input cable from the ground terminal. After that, also check all the wires with a test lamp and, again by the elimination method, in the position when the lamp is off, identify the ground conductor.

As you can see, in different situations, at different schemes wiring implemented in the apartment, the methods and methods for determining zero, phase and ground are changing. If you encounter a situation that is not described in this article, be sure to write in the comments to the article, we will try to help you.
And if you know more simple ways how to determine the phase, zero and ground at home, without a specialized tool, write in the comments. The article will be updated for sure. The main requirement for the methods of determination is simplicity, the ability to get by in the search with only improvised, household means that many have.

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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 should be marked in different colors. 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.
• Phase got the richest palette, it is gray and red, pink and turquoise, orange and purple, but most often - brown, black or white.

But sometimes a home master will have an unpleasant surprise in the form of wires of the same color. Or even worse - wires of one color stretch from the shield to the apartment, and another one 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 sure of your caution and accuracy, go for it!

Looking for a phase

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

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

After that, you can release the wires from the insulation and, having applied voltage to the apartment, proceed to search for the phase using an indicator screwdriver. Hold the tool only by the protective housing, positioning forefinger on the metal end of the handle. Alternately touch the tip of the screwdriver to the wires. Phase - the one on which the indicator lights up. If the wire is two-core, this is enough: the second conductor is zero. In the case of a three-core, you will have to continue researching with 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 AC voltage in the range above 220 volts. With one of the probes of the device we touch the phase found earlier, with the others - first to one of the unidentified wires, then to the other. We look at what voltage value the multimeter shows in each of the cases. 220 volts corresponds to zero, when touching the ground, the value will be less.

By the way, with the help of a multimeter, you can also determine the phase. The measurement range will be the same - above 220 volts. With the probe that stretches from the socket marked V, we alternately touch the wires. The phase will signal itself with an indicator of 8-15 volts, and zero - zero on the scale of the device.

The need to figure out where the phase wire is located, and where is the zero one, can arise for any owner of a house or apartment. This may be necessary when carrying out the simplest electrical installation work, for example, installation of switches and sockets, replacement of lamps. Sometimes this is important when diagnosing malfunctions of the home electrical network, performing preventive or repair measures. Yes, 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 operation.

So, you need to learn how to independently determine the phase and neutral wires. This is not so difficult - there are proven methods using simple and inexpensive devices. But here are some users, it is not clear for what reasons, they ask the question in search engines: how to determine the phase and zero without devices? Well, let's discuss this problem.

In the overwhelming majority of cases, the laying of a single-phase power supply network 220 V / 50 Hz is practiced in apartments. To high-rise building a three-phase power line is supplied, but then in switchboards switching is carried out to consumers (apartment) in one phase and a neutral wire. They try to distribute the distribution as evenly as possible so that the load on each of the phases is approximately the same, without strong distortions.

In houses modern building practiced laying and contouring protective earth– modern powerful Appliances for the most part requires such a connection to ensure safe operation. Thus, to sockets or, for example, to many lighting fixtures fit three wires - 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 appliances is not up to par. Therefore, when carrying out overhauls housing stock often included are measures to improve internal power networks - a 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 three-phase voltage 380 volts. For example, it can be a heating boiler or powerful technological machine tools in a home workshop. But the internal "household" network is still made single-phase - just three phases are evenly distributed along different lines in order to prevent skew. And in any ordinary outlet, we will still see the same three wires - phase, zero and ground.

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

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

To have a protective ground loop in your residential property means to significantly increase the level of safety in the operation of electrical appliances. And by by and large- and in general the degree of safety of living in the house for the whole family. If it is not there yet, 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, can be considered conditional. This is about color coding wires laid power cables and wires.

Indeed, there is an international standard IEC 60446-2004. It must be followed 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 must be blue or light blue. Protective grounding is most often distinguished 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, this is not a dogma at all. Very often there are other colors - 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 won't be mistaken. So why is this the only way to recognize wires without devices is still considered conditional?

The only thing is that such a color "pinout" is adhered to, alas, far from everywhere and not always. About the houses of the old building - and there is no need to talk. There, the wiring is mostly made with wires in exactly the same white insulation, of course, saying nothing to anyone.

Yes, even in the case when cables with insulated wires are laid different colors, you need to be absolutely sure that the conductive electric installation work specialists strictly followed the rules. Often called "masters", invited from outside, take liberties in these matters. So, you can be sure if the work was controlled, carried out really professional electrician with an impeccable reputation. Or if during the operation the owners already had the opportunity to make sure that “ color scheme» complied with. And, finally, if the landlord did all the laying on his own, strictly guided by 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 some 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 ways to determine zero and phase, using some "exotic" devices like raw potatoes, it's completely wrong. The author of the article and never did not indulge in such methods, and others will never, under any circumstances, recommend.

We will not even touch on the reliability of such checks. The main thing is not this. Such "experiments" are extremely dangerous. Especially for an inexperienced person in the electrical economy. (And an experienced one, believe me, is always better to use a really reliable and safe technique). In addition, young children can see such manipulations as a sin. Will it not be disturbing later, knowing about the inherent desire of the baby to imitate parents in many ways?

And, by and large, it is hardly possible to imagine a situation in which 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 wait until the morning with the diagnosis? Yes, after all, you can’t ask a neighbor for an indicator for a few minutes?

By the way, potatoes are something else ... There are "specialists" who, in all seriousness, recommend checking for the presence of a phase by lightly touching the conductor with a finger. Like, if in a dry room, but in shoes with dielectric soles, then nothing bad will happen. I would like to ask such "advisers" - are they sure that all those who heeded their recommendations are alive and well? That an “emergency” did not happen when a person trying the phase “by touch” accidentally touched a grounded object or another 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" poses to life and health. electricity on a 220 volt network. Perhaps after that, many questions will be removed by themselves.

"Household" alternating voltage of 220 volts can be a mortal danger!

A life modern man unimaginable without electricity. But it does not always act only in the role of "friend and helper." If the rules for the operation of devices are neglected, with negligence, inaccuracy, and even more so with a clearly disregard for compliance with safety requirements, it can punish instantly and extremely cruelly. A separate publication of our portal tells in detail about for the human body.

And so, let's summarize. No way, except for the one mentioned, to independently get ahead of the location of zero and phase without instruments - does not exist.

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

Determination of phase and zero in various ways

Using an indicator screwdriver

This is perhaps the simplest and most affordable method. As already mentioned, the cost of the simplest device is very low. And learning how to work with it is a matter of a few minutes.

So, how does a regular indicator screwdriver work:

All the “stuffing” of this probe is assembled in a hollow body (pos. 1) made of a dielectric material.

The working body of such a screwdriver is a metal sting (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 bare end of the tip is usually small. The sting goes short by itself, go "dresses" in an insulating sheath.

Important - the tip of the indicator screwdriver should be considered exactly as a contact tip when testing. Yes, if necessary, they can perform the simplest assembly 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 is simply not designed for high loads.

The metal rod of the sting, which enters the housing, becomes a conductor, providing contact with the internal circuit of the indicator. And the circuit itself consists, firstly, of a powerful resistor (pos. 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 ​​\u200b\u200bsafe for humans.

The next element is a neon light bulb (pos. 5), which can light up with very small currents flowing through it. The mutual electrical contact of all elements of the circuit is provided by a pressure spring (pos. 6). And it, in turn, is compressed by a plug screwed into the end end of the housing (pos. 7), which can be either completely metal or having a metal “heel”. That is, this stub plays the role of a contact pad during checks.

When touching the contact area with a finger, the user is "turned on" to the circuit. The human body, firstly, in 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 sting of the indicator screwdriver touches the stripped conductor (the terminal of a socket or switch, another thin-bearing part, for example, a contact lobe of a light bulb socket). Then the contact pad of the probe is touched with a 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 light bulb.

In the same case, if the check fell on the zero contact, there will be no glow. Yes, there is also little potential, especially if others are working in the apartment (house) at that time electrical devices. But the current due to the resistor will be so small that the indicator should not glow.

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

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

A slightly different check is performed with an indicator screwdriver of a more advanced type. Such probes allow not only to determine the phase and zero, but also to carry out continuity of circuits and a number of other operations.

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

If you are not sure which specific screwdriver the user has at his disposal, a simple test can be carried out. Just touch both the sting and the contact pad at the same time. The circuit will then close, and the LED will signal this with its glow.

Why is all this being said? Yes, simply because the algorithm for determining the phase and zero when using such a screwdriver changes somewhat. Specifically, touching the contact pad is not required. Simply touching the phase conductor will cause the indicator to glow. There will be no such glow at working zero and on ground.

Nowadays, more expensive indicator screwdrivers, with electronic filling, light and sound indication, are also widely represented 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 similarity

It's not that hard to use either. 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 test that the capabilities of the device used correspond to the mains voltage. This is usually indicated directly on the indicator housing.

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

The convenience of such a device is also that it is not at all necessary to strip the wire under test from insulation. The device does not respond to contact, but to the electromagnetic alternating field created by the conductor. At a certain voltage, the circuit is triggered, and the device signals that we have a phase wire in front of us by turning on the light and sound signal.

Determination of phase and zero with a multimeter

Another control and measuring device that any skilled home owner would need to acquire is the cost of inexpensive, but sufficient 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 using 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 elimination method can be applied.

This is done as follows:

• The multimeter is ready to go. The black test lead is connected to the COM connector, the red test lead is connected to the voltage measurement connector.
• The operating mode switch is moved to the sector allocated for measuring alternating voltage (~ V or ACV), and the arrow is set to a value exceeding the mains voltage. AT different models it can be, for example, 500, 600 or 750 volts.

• Next, voltage measurements are taken between the previously stripped conductors. There are three possible combinations in this case:

1. Between phase and zero, the voltage should be close to the nominal value of 220 volts.
2. There can 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. If there is no RCD, or the leakage current is quite insignificant, then the voltage, again, is around the nominal value.
3. There should be no voltage between zero and ground.

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

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 appropriate inscriptions on them.

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

• Preparing the multimeter for work - according to the same scheme as shown above.
• Next, a control voltage measurement is carried out. Two goals are being pursued here. First, you need to make sure that there is no break in the line, and we will not look for the phase and zero, as they say, from scratch. And secondly, the device itself is tested. If the readings are correct, then 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.
• The red test lead touches the conductor under test. If this is a socket, then a probe is inserted into the socket, if the stripped end of the conductor is better to use the “crocodile” clip.
• The second probe is touched with a finger right hand. And - observe the readings on the display of the multimeter.

— If the control probe has been set to zero, no voltage will 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 value is not so important - it depends on the very a large number factors. This is the established measurement limit of the multitester model used, and the features of the resistance of the body of a particular person, and humidity, and air temperature, and the shoes that the master is wearing, etc. The main thing is that there is tension, and it is strikingly different from the second contact. That is, the phase is found.

Probably, not everyone will be able to overcome the psychological barrier - touch the probe with your hand when the multitester is connected to the outlet. There is nothing to be afraid of here - we previously 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 prichologically impossible.

It's okay, you can do it a little differently. For example, just touch the wall with the second probe - 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 is used as the second contact, for example, a heating radiator or water pipe. Suitable and metal carcass, even without grounding. And sometimes even one probe connected to the outlet with the second, just lying on the floor or on the table, allows you to see the difference. When testing a phase, the tester can show units or a couple of tens of volts. With a zero conductor, of course, there will be zero.

AT. With the definition of the phase, as you can see, there are no particular problems. 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 two remaining ones is zero, and which is protective ground.

But this is not so simple. There are, of course, several ways available. But none of them can claim to be "the ultimate truth." That is, it requires special devices that are available to professional electricians.

But sometimes self-testing helps.

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

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 ohms and, in without fail- having switched off the voltage on the shield, measure the resistance between these conductors and a guaranteed grounded object one by one. On the PE conductor, this resistance should, in theory, be much lower.

But, again, this method is not reliable, since the connections are practiced differently, and the values ​​\u200b\u200bmay turn out to be approximately the same, that is, they do not say anything.

Another option is to disconnect the ground bus from the circuit leading to it. Or remove from it the alleged wire to be checked. Then - either perform a ringing, or alternately measure 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 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 completely reliable.

Find out and also get acquainted 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 grounding, but it is not possible to find out yourself, it is better to contact a qualified electrician. Despite the similarity of these conductors in home wiring, they should never be confused.

So, the main available ways phase and zero definitions. 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 sorts of potatoes, plastic bottles, jars of water and other "toys" - completely unacceptable!

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

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

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

Check functionality electrical networks in an apartment or a private house can be different ways. From a financial point of view the best option there will be an indicator probe that can replace a multimeter at home.

When performing installation work with sockets and light switches, it often becomes necessary to find the phase and zero. Of course, for experienced electricians, such a task is a trifle, but for those who are not familiar with the rules of the device electrical networks, this question can drive into a dead end.

indicator screwdriver. Nuances in use

Considering the number of electrical appliances in each apartment, everyone should have this device. With it, it will be possible to determine the presence of current in any conductor, socket or electrical panel.

The design of the indicator screwdriver

The design of an ordinary probe in the form of a screwdriver is simple:

• probe, acts as a conductor;
• a resistor is connected to the sting, it is needed to lower the current strength to a value that is safe for the human body;
• then there is an LED that is connected to the contact patch brought to the end of the screwdriver;
• body is made from transparent plastic, this allows you to see the LED lighting up.

Phase and zero in a screwdriver

Finding the phase and zero with an indicator screwdriver is not difficult. When the probe touches a live wire, the current will pass through the rod, then through the resistor, cause the LED to glow, and then fall on the hand that touches the metal plate. The current will also pass through the body of the person who performs this operation, and then leave the ground.

The person himself will not feel the current passing through him, since its value is too small.

Application area

Any work that relates to electrical wiring must be safe. For this purpose, everyone should have this necessary tool in the house.

This device can be used for the following purposes:

• check to which contact of the socket or switch the phase conductor is connected;
• when the extension cord outlet is not working, you can check all the sockets with a probe;
• with its help, you can find out where the phase is connected in the cartridge: to the central contact or to the thread;
• find out if the electrical appliance is energized;
• by touching the tip of the tool to the central contact of the socket, you can check the serviceability of the grounding conductor.

Important! If the power grid alternating current, then there is no need to press your finger against the plate!

Screwdriver types

New models of screwdrivers can detect the presence of stress in the strand even through a layer of whitewash, plaster and clay. Their algorithm of action is almost always the same. But there are also differences that arise depending on the types, models and a number of functions that the tool has.

Sometimes, in terms of its functionality, one screwdriver can replace several expensive devices. There are devices with a battery, this makes it possible to check the health of the wire, even in a de-energized state.

Important! Any indicator screwdriver has lower and upper voltage measurement limits. Exceeding them may break the device or display incorrect information.

Such a model can give maximum amount interesting information about the circuit under study:

• a beep will indicate that there is voltage in the circuit;
• the digital display will display the voltage value in volts;
• makes it possible to check the circuits of the alternating and direct current in household electrical appliances;
• determine the polarity of the networks;
• with its help, you can carry out the continuity of the electrical circuit with a light or sound indication.

Checking the device before use

Before use, the indicator device must be checked for serviceability. The battery that is inside the device will help make sure of this. You will need to touch the sting and the other finger to the metal contact on the handle at the same time. The indicator light should light up at this point.

If the device does not provide for a battery, then a live conductor is needed. You need to touch it with the tip of a screwdriver, and the metal on the handle with your finger. As a result, the LED will also glow.

Basic Security Measures

Be sure to follow the precautions:

• it is forbidden to use a probe without a screw;
• only batteries can be removed from the device;
• after the battery is replaced, the screw should be tightened clockwise until it stops;
• if the probe has mechanical damage, then its use is prohibited;
• do not use the device above the limits specified in the technical specifications;
• before using the probe, you will need to check it in the network with the exact presence of a phase;

Important! When measuring electrical lines, the probe is held only by insulated elements. Exceptions are circuits without voltage.

Instructions for use

According to their characteristics, such indicator devices are intended for:

• the ability to determine the alternating voltage by contact method up to 250 V;
• non-contact method up to 600 V;
• examination of the circuit for integrity from 0 to 2 MΩ;
• establishing polarity: from 1.5 V to 36 V;
• the tool must be stored in a dry and moisture-protected place;
• all operations are best done with gloves to ensure contactless examination;
• after work, the tool should be cleaned of dust and debris.

Non-contact screwdrivers are very sensitive, it can respond to both phase and neutral, although the real voltage will be in only one wire. Therefore, for an ordinary electrician, such a screwdriver is not needed. However, it can help in checking the quality of cable shielding and the absence of radiation.

In such devices, there are three switch positions. Two are provided for remote action. In the event that a screwdriver accidentally touches the current-carrying part of the wire in this mode, the entire electronic part, consisting of transistors and an LED, will burn out.

Electrical appliances surround a person in Everyday life. Sooner or later in any electrical system problems and problems occur. These problems are not always worth inviting an experienced electrician; some breakdowns can be fixed on your own. However, to be able to find a fault in the network, you will definitely need special tool, which costs, purchase in advance.

In this article, we will consider the question of how to find the phase and zero using a probe and a multimeter.

If it is necessary to service apartment electricians, in particular, to replace sockets, light switches, or carry out minor repair work, it becomes necessary to determine the phase and zero. If a person has some knowledge of the basics of electrical engineering, then it will not be difficult for him to find the phase and zero. But what if you don't have these skills? The search for phase and zero is not the same difficult process as it may seem. Consider several ways to determine the phase and zero.

First, let's define what phase and zero are. Our entire energy system is three-phase, including low-voltage lines that feed houses and apartments. As a rule, the voltage between any two phases is 380 volts - this is line voltage. Everyone knows that the voltage of the household network is 220 volts. How to get this voltage?

For this, a neutral wire is provided in electrical installations with an operating voltage of 380 volts. If we take one of the phases and the neutral wire, then there will be a potential difference of 220 volts between them, that is, this is the phase voltage.

For a person who does not have knowledge in the field of electrical engineering, the above is not very clear. It is important for us to know that one phase and one zero comes to each apartment or house. In detail, what is phase and zero is considered.

So, you have two wires and you need to determine which one is phase and which is zero. First, it is necessary to de-energize them by turning off the circuit breaker that feeds this line of electrical wiring.

Then it is necessary to strip both wires, that is, remove 1-2 cm of insulation from it. The stripped conductors must be slightly separated so that when voltage is applied, a short circuit does not occur as a result of their contact.

The next step is to determine the phase wire. We turn on the machine, through which voltage is applied to the conductors. We take the indicator screwdriver by the handle and touch the metal part at the base of the handle with one finger.

Remember that it is strictly forbidden to take the probe below the handle, that is, by the working part. We bring the probe to one of the wires and touch it with the working part. In this case, the finger remains on the metal part of the handle.

If the lamp of the indicator screwdriver lights up, then this wire is phase, that is, phase. The other wire, respectively, is zero.

If the probe lamp does not light up when you touch the wire, then this is the neutral wire. Accordingly, the other wire is the phase, you can check this by touching the indicator screwdriver.

But what if the wiring in the apartment is made with three wires? In this case, you have not only phase and zero, but also. Using a probe, you can easily determine which of the three wires is the phase.

But how to determine where is zero, and where is the protective conductor, that is, the grounding conductor? In this case, one indicator screwdriver is not enough. Consider a method for determining zero in a three-wire household network.

You can determine where is zero, and where is the protective (grounding conductor), using a multimeter. So, we have already determined the phase wire using a probe. We take a multimeter and turn it on for a measurement range of alternating voltage of 220 volts and above.

We take two probes measuring device and touch one of them to the phase, and the other to one of the two remaining conductors. We fix the voltage value that the multimeter shows.

Then we leave one of the probes in phase, and with the other we touch the other wire and again fix the voltage value. When touched simultaneously to the phase and to zero, the value of the voltage of the household power supply, that is, approximately 220 volts, will be displayed. If you touch the phase and the protective conductor, then the voltage value will be slightly less than the previous one.

If you do not have a probe, then the phase can also be found with a multimeter. To do this, we select the measurement range of alternating voltage with a value above 220 volts. Two probes are connected to the multimeter in the "COM" and "V" sockets, respectively.

We pick up the probe that is included in the socket marked "V" and touch it to the conductors. If you touched the phase, the device will show a small value - 8-15 volts. When you touch the neutral wire, the readings of the device will remain at zero.