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How to find phase and zero? Several methods for detecting phase and neutral wires

 

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 the apartment electricians, in particular the replacement of sockets, lighting switches or minor repairs, it becomes necessary to determine the phase and zero. If a person has some knowledge in the field of the basics of electrical engineering, then it will not be difficult for him to find phase and zero. But what if you do not have these skills? Finding phase and zero is not as complex a process as it might seem. Consider several methods for determining phase and zero.

How to find phase and zero? Several methods for detecting phase and neutral wires

First, we will determine what phase and zero are. Our entire energy system is three-phase, including low-voltage lines that feed residential buildings and apartments. As a rule, the voltage between any two phases is 380 volts - this is a linear voltage. Everyone knows that the voltage of a household network is 220 volts. How to get this voltage?

For this, in electrical installations with a working voltage of 380 volts, a neutral wire is provided. If you take one of the phases and the neutral wire, then between them there will be a potential difference of 220 volts, 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 in each apartment or house comes one phase and one zero. In detail what phase and zero are considered here

Consider the first way to determine the phase using a probe (indicator screwdriver). You can read more about the device and the principle of operation of such screwdrivers here - Voltage indicators and indicators in electrical installations up to 1000 V.

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

Then it is necessary to strip both wires, that is, remove 1-2 cm of insulation from it. Stripped conductors need to be slightly diluted so that when a voltage is applied, there is no short circuit as a result of their contact.

Voltage indicators

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 with one finger we touch the metal part at the base of the handle.

Remember that it is strictly forbidden to take the probe below the handle, that is, for 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 indicator screwdriver light comes on, 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, another wire is a phase, you can check this by touching the indicator screwdriver.

How to find phase and zero

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

But how to determine where is zero, and where is the protective conductor, that is, grounding? In this case, one indicator screwdriver is indispensable. Consider the method of determining zero in a three-wire household network.

Determine where zero is, and where is the protective (grounding conductor), using a multimeter. So, we have already identified the phase wire using a probe. We take a multimeter and turn it on to the range of measuring AC voltage of 220 volts and above.

We take two probes of the 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 touch the other wire and again fix the voltage value. When you touch the phase and zero at the same time, the value of the voltage of the household power supply, i.e. 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.

Multimeter

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

We pick up the probe that is plugged into the socket labeled “V” and touch it with the conductors. If you touch the phase, the device will show a small value - 8-15 volts. When you touch the zero wire, the readings of the device will remain at zero.

We recommend reading: What should I do if the phase of the 220 V sockets on both connectors?

See also at bgv.electricianexp.com:

  • How to determine the ground wire
  • Why does the switch open the phase, not the zero?
  • What to do if the chandelier does not work
  • Two phases in your 220 volt outlet? This is more real than you think.
  • Wire color coding

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    Comments:

    # 1 wrote: Maksim | [quote]

     
     

    There is another way to determine phase and zero using a pilot lamp. The control lamp in its simplest version is a conventional lamp screwed into a cartridge, to which two probes are connected. To determine the phase and neutral wires, you need to connect one probe to the metal pipe of the apartment pipeline, and with the other probe touch the wires one by one. When you touch the phase conductor, the lamp lights up, and when you touch the neutral conductor, the lamp will not light.

     
    Comments:

    # 2 wrote: | [quote]

     
     

    The administrator has accurately described everything, but the lamp will explode by the way and this is prohibited by the rules.

     
    Comments:

    # 3 wrote: Andrew | [quote]

     
     

    Thanks to the author. Article 5 points. And I think that it is necessary to use normal devices, because they are not so expensive, but all inventions and grandfather methods and devices must be forgotten.

     
    Comments:

    # 4 wrote: ofris | [quote]

     
     

    "... the metal pipe of the apartment pipeline" - quote No. 1
     
    For a person who does not have knowledge in the field of electrical engineering, the above is not very clear - quote number two.
    -----------------------------------------------------------
    So explain to the “teapot" what quote number 1 is!

    It would also be necessary to say that all switches work with "zero" therefore with the wires of the switch - after checking the indicator - you can work with your bare hands.

    # If you touch the phase and the protective conductor, the voltage will be slightly less than the previous one. "
    A few volts or several tens of volts?
    You need to chew thoroughly!

    But in general, the article is informative. Thanks to the author.
    I ask, nevertheless, to illuminate in more detail the search and determination of a working grounding conductor.

     
    Comments:

    # 5 wrote: Ruslan | [quote]

     
     

    So, we figured it out. What's next?

     
    Comments:

    # 6 wrote: | [quote]

     
     

    Maksim,
    There is another way to determine phase and zero using a pilot lamp. The control lamp in its simplest version is a conventional lamp screwed into a cartridge, to which two probes are connected. To determine the phase and neutral wires, you need to connect one probe to the metal pipe of the apartment pipeline, and with the other probe touch the wires one by one. When you touch the phase conductor, the lamp lights up, and when you touch the neutral conductor, the lamp will not light.

    Yes, and wherever the plumber will change the pipe, and will get into the circuit, under voltage. And will die.

    No need to do that.

    If you do not have a probe, then the phase can also be found with a multimeter. To do this, select the measuring range of the AC voltage value above 220 volts.Two probes are connected to the multimeter in the sockets “COM” and “V”, respectively. We pick up the probe that is plugged into the socket labeled “V” and touch it with the conductors. If you touch the phase, the device will show a small value - 8-15 volts. When you touch the zero wire, the readings of the device will remain at zero.

    With this method, it is very important to warn about the importance of choosing the position of the "voltmeter" on the multimeter, otherwise suddenly a person will want to tinker with the probe, and then switch the multimeter, and then the position, for example, "ammeter", and death as a maximum.

     
    Comments:

    # 7 wrote: | [quote]

     
     

    Maksim, or will burn, but less brightly. In a certain scenario, it can burn the same. In this case, we go around the apartment and pull out everything from the sockets, turn off all the switches. The control can be replaced with a multimeter, preferably with a small input impedance (with a large one you can make a mistake). For the invention of the control bulb, you need to give the Nobel Prize, how many times it helped out, although it is a sin to deny its danger.

     
    Comments:

    # 8 wrote: electrician | [quote]

     
     

    that the voltage between the ground and the phase is less than between the phase and zero - Nonsense.

    It all depends on how many devices are on, morning or evening, etc. The network is 3-phase

     
    Comments:

    # 9 wrote: Maksim | [quote]

     
     

    electrician, if you are sure that this is nonsense, then why don't you share your experience and tell how to determine it correctly? More than sure that you yourself do not know how to correctly determine where the ground is and where the ground conductor is.

     
    Comments:

    # 10 wrote: | [quote]

     
     

    Multimeter DT-832. About 7 years ago it cost about 4 bucks.

    When the tester is turned on for 750 ACV, 001 is constantly lit on the display

    When you touch one of the wires of the socket with a V probe, it shows 002 V. On the second wire, 001. On the other socket, it shows 003 on one wire and 001 on the second.

     
    Comments:

    # 11 wrote: | [quote]

     
     

    The method described in the article how to distinguish the neutral wire from the protective wire is in doubt. It all depends on the quality of the zero wire contact in the switchgear. Ideally, the potentials of the neutral and protective wires are the same. If the control becomes on the phase and protective wire, then the RCD will trite work (if it is)

     
    Comments:

    # 12 wrote: | [quote]

     
     

    Everything that is written about the use of the voltage indicator agrees, but the method for determining the phase using a multimeter is debatable. There are many nuances and it may actually turn out that not everything is as simple as it is written in the article and finding a phase with a multimeter does not work. But for a general understanding, the article is good. Just if the simple methods described in the article to determine the phase and neutral wire does not work out, then look for professionals who can do this taking into account their experience and all the subtleties and nuances.

     
    Comments:

    # 13 wrote: Vladimir | [quote]

     
     

    The search for neutral and ground conductor is not convincing.

     
    Comments:

    # 14 wrote: Andrew | [quote]

     
     

    The land determination method does not work! In both wires the same reading 215 and all ...

     
    Comments:

    # 15 wrote: Oleg | [quote]

     
     

    In the end, how do I find the phase? I have both testers and phase and zero by zeros !!

     
    Comments:

    # 16 wrote: Oleg | [quote]

     
     

    Of course, a screwdriver probe is much more convenient. If the probe is with batteries, then you can not strip the wires - it shows at a short distance.

    I was also looking for a phase tester. One probe hangs in the air (in the sense, nothing concerns), the second I poke into the wires. Where more will show, there is a phase. Approx shows several volts. In my tester, the limit is automatically set. If you have a minimum limit of 750 V., then you won’t define it. You need to poke somewhere else with a second probe, except for air;) - it will show almost 220. If a tester with a large voltage resistance (I have about 11 megaohms) - you can poke into the battery and grab your hands - the current is about 20 microamps maximum will do harm. I tried it myself, but you better not risk it :)

    About the definition of zero and earth relative to the phase - once measured, no difference (+ - a pair of volts). This is the same wire. There should be no difference in voltage. Perhaps I am mistaken, justify, if not so. :)

     
    Comments:

    # 17 wrote: Evgeny | [quote]

     
     

    Is this a solution?
    If the control lamp is on the phase and protective wire, then the plugs will fly out, and if the phase is zero, it will light up quietly.

     
    Comments:

    # 18 wrote: | [quote]

     
     

    "Remember that it is strictly forbidden to take the probe below the handle, that is, for the working part." - in the very first picture, this condition is almost met. There was only a centimeter left until you received complete pleasure. And so you have to be able to stretch your fingers).

     
    Comments:

    # 19 wrote: | [quote]

     
     

    The purpose of the cores - phase, neutral and earth is necessary for the correct connection of sockets, switches, fixtures and devices - a water heater, dishwasher and sometimes a washing machine.

    It makes sense to use an earthen conductor only in a 3-wire wiring system for grounding the metal case of the device and when using an RCD (diffuser).

    Modern wiring made by VVG ng or NYM cable are color-coded.

    A red, brown or white or white with these colors vein should be connected to the phase, blue (blue) to the neutral, yellow-green to the ground.

    Therefore, with proper installation, after opening the outer insulation sheath, one should expect: red - phase, blue - neutral, yellow-green - earth.

    But for reliability I use a sound probe IEK OP-2e. I work under tension.

    Without experience, this does not work!

    On a flat cable VVG ng, you can use the indicator to find the phase core without opening the insulation. The screwdriver sting of the indicator turned on L or H, I bring it to the edge of the outer sheath of the cable.

    On the one hand, the indicator lights up and the green color lights up, on the other, no. Where buzzing, there is a phase.

    It is difficult to distinguish neutral from earth. But on the long loaded line in the house there are voltage losses. I turn on the indicator in O mode and touch the core opened with insulation with the sting of a screwdriver.

    The phase core on the indicator shines bright red.

    Neutral, due to voltage loss, barely shines in red.

    Earth does not shine at all - earth potential is not supposed to have any potential.

     
    Comments:

    # 20 wrote: | [quote]

     
     

    ofris,
    According to the rules for the installation of electrical installations (PUE), in accordance with paragraph 6.6.28 of the section "wiring products", "3-pole or 2-wire single-phase networks can use single-pole switches that must be installed in the phase wire circuit", i.e. ON THE SWITCH SHOULD BE CONNECTED "phase". After turning on the switch, the "phase" enters the chandelier. When turned off, the "phase" does not move to the chandelier and you can safely change the bulb.
    If “zero” is applied to the switch, then a “phase” will always be connected to the chandelier, which is not permissible, since when changing a bulb, it can lead to electrical injuries.

     
    Comments:

    # 21 wrote: | [quote]

     
     

    As Mephistopheles used to say: "Dry theory, my friend ..."
    If there is neither an indicator screwdriver nor a multimeter at hand, you can determine the phase and zero in the socket at once: if you insert a long screwdriver into the socket and rub the bare part of the screwdriver with the back of your fingers, then you will feel a slight “friction” against the screwdriver if it "phase" (effect of alternating voltage of 50 Hz). At "zero" - "friction" is not felt. At the same time, it is necessary to observe the SAFETY PRECAUTIONS (!!!): you should be shod in dry shoes so as not to get "pleasure" from the voltage of 220 V. !!!

     
    Comments:

    # 22 wrote: MaksimovM | [quote]

     
     

    Alexander, touching bare metal elements that are energized by the household network, that is, a screwdriver inserted into the outlet, is already a gross violation of safety precautions. You can’t advise people like that! When you touch the phase wire, a person will be shocked.

    Even if we assume that the shoes will provide isolation of the person from the ground, the possibility of touching the person at the same time to the phase wire and grounded metal elements of electrical appliances or the grounding contact of the outlet is not excluded. That is, in this case, a person falls under the influence of an electric current that will flow between his hands or other points of the body that touch metal elements with different potentials.

     
    Comments:

    # 23 wrote: Evgeny | [quote]

     
     

    We take a movie - we put a red probe in the socket. Black do not touch. If there is a phase, it will show "-" and / or 1-3 Volts. On zero it will not show anything. At least I had it