certain phase. How to determine the ground terminal, zero and phase in the outlet

When repairing electrical wiring, or maintaining 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 most common misconceptions associated with the definition of the neutral and phase wires:

An example of such equipment is a controller that controls the operation of a gas boiler. When the error "not enough voltage" 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 there are three cores in the cable, and one of them is multi-colored, then it is grounding. One can never be sure of this, especially given the confusion with GOSTs in the last decade of the last century. Therefore, it is better to always check the cable.

Color coding

In order not to bother yourself 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.

It is not necessary to trust the color coding if you have the slightest doubt. It is better to once again make sure that the purpose of the wires matches the colors.

The most accessible and common ways

The simplest way, which allows you to accurately determine the phase and neutral wires, is performed with an indicator screwdriver. You can buy it or build it yourself. The scheme 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 of 1.5 to 2 MΩ, power from 0.5 W;
HG1 - any type of neon lamp.

Video instruction: determining the phase and zero with an indicator screwdriver

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

Determining the connection of a wire to a phase or phase zero (in a two-wire electrical circuit) produced according to the step-by-step algorithm described below:

the wiring is de-energized;
the protective layer of insulation is removed from the wires to be tested (one centimeter will be enough);
we turn on the electricity, since it will not work to determine zero if the phase is off;
two wires are checked in turn with the tip of the probe, while touching the contact plate of the indicator, as shown in the photo;
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 puzzle a novice electrician. The matter will be even more confused 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. That is why you can not neglect the voltage probe.

To solve this problem, it is enough to eliminate a 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-core 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:

using a probe, we determine the phase;
measure the voltage between the phase and the remaining two wires;
the potential difference between zero and phase will be around 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 measurement range of alternating current to more than 220V. The probes are connected to the V and COM jacks (shown in the photo below).

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

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

No required appliances

The household should have at least a voltage probe, but if you don’t have one, don’t be discouraged, there are ways to determine the ground, zero and phase without devices.

All that is required of you is to make a control lamp, approximately the same as 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 ensure reliable insulation at the points of attachment of wires to the lamp and probes. Naturally, if you need to test the wires in the box on the ceiling, you need to make probes of the appropriate length.

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

The wire, when touched, the lamp will glow, and will be the 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 that the repetition of such dubious experiments can cause significant damage to your health.

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

13.06.2019

If it becomes necessary to determine the zero and phase core, suitable devices may not always be nearby. Conductors can be identified using improvised means, but it is necessary to strictly follow the safety rules when handling electric current.

By wire color

You can find out the purpose of the core by the color of its insulation. There is a standard for color marking conductors. Neutral wires are usually denoted in blue or blue. Grounding can be found by the green color of the insulating material. However, here it is also permissible to use yellow markings or a combination of green and yellow colors.

With a phase wire, the situation is more difficult. The palette of shades of its designation is quite wide:

White;
the black;
Red;
Brown;
Gray;
Orange;
pink;
purple.

There are even phases of turquoise color. In this case, you should be very careful not to accidentally confuse it with green ground or blue zero.

Strictly speaking, determining by the color of the insulation is not the most reliable way. Therefore, experts often call it conditional. Firstly, color marking is far from always found - for example, in old buildings they used exclusively white insulation for all cables. Secondly, electricians themselves often neglect the established marking rules, connecting to the system those wires that are at hand.

Test light bulb

It is worth mentioning right away that this method of verification is very dangerous. All manipulations are recommended to be carried out taking into account safety rules and only with rubber gloves.

The control lamp is made independently. For this you need the following materials:

an ordinary incandescent lamp with a cartridge in working condition;
2 stranded wires, about half a meter long.

The cores are attached to different sockets of the cartridge. One wire is connected to a metal object, and the other to a core that needs to be identified.

Determining the result of such a check is very simple.

If the light bulb lights up, it means that the phase lived, if the reaction did not occur, it is zero.

By the way, if you don’t have a regular light bulb at hand, you can just as well check with a neon lamp.

Folk way

There is also a popular way to identify the zero and phase conductors. Despite the fact that some experts treat it rather sarcastically, this method works quite effectively.

You will need the following items to define:

2 stranded wires, about half a meter long;
1 MΩ resistor;
large potato.

The test circuit resembles the phase identification on a control light. One end of the wire is attached to the metal (often heating or water pipes are used), the other is tightly adjacent to the potato cut along. The second conductor is also adjacent to the vegetable, and its other end is connected to the resistor and the core of interest.

It is very important that the wires in the potato are as far apart as possible.

The result of the study will have to wait about 10 minutes. Upon contact with the phase, the pulp of the vegetable will darken, and in the case of zero, it will remain unchanged.

You can check the purpose of the conductor using improvised means. But such methods are far from safe. Therefore, they should be used only in extreme cases. Better yet, get a special indicator screwdriver.

Chapter:

Simple ways to determine phase and zero without instruments: 14 comments

Yuri
Text from the article The veins are attached to different sockets of the cartridge. One wire is connected to a metal object, and the other to a core that needs to be identified. My actions, I connect one wire to a metal object (for example, a nail or a ladle, or a dinner fork, it is also made of iron)
The author study the PUE iPTEE the use of controls is prohibited
Alexander
Determine phase and zero? Elementary Watson; no utensils or potatoes needed! The test is carried out - under voltage (!!!). I share my own experience: you just take an ordinary screwdriver more authentic, contact it with the wire of interest, holding the handle of the screwdriver with one hand, with the other hand - with the back of a dry (!) Hand (fingers) - run along its metal part. If this is a phase, then the hand feels “rubbing” on the screwdriver; if “friction” is not felt, the wire is zero. The effect of "friction" - from alternating current 50Hz. (!!!)Of course, at the same time, you must be in some kind of dry shoes so as not to come into contact with the floor (ground). And - may the holy Om bless you!
Henry
Especially for the author of this publication, a personal recommendation is to check the phase for the language. For more precise control, stand barefoot in a puddle of salt water. Attention!!! this is black humor, the recommendation is deadly!!! The color marking of wires is like a zebra at a pedestrian crossing, the driver is obliged to slow down, but does everyone slow down ??? The so-called control lamp cannot always show the presence of a phase. As well as the indicator screwdriver. And for everyone else: don't experiment with dangerous things you don't understand. To control the voltage, there are conventional devices: voltmeters, testers, multimeters. Well, if you don’t have a device at home (then most likely you don’t have experience either), then it’s better to invite an electrician from the Housing Office. Well, or another professional master. People have been gaining experience for years, and then the author came and spread everything on his fingers. Moreover, all people have teeth, but even I don’t see articles on the net on how to fill a tooth at home, or how to remove a child’s appendix before an ambulance arrives
Nicholas
If you don’t have anything from a power tool that allows you to distinguish phase from zero, then you are most likely not an electrician, and therefore you shouldn’t try to figure something out at all ... Call a professional and he will solve your problems and possibly extend your life ...
And all this advice is complete and irresponsible nonsense.
Michael
Never do as advised in the article. At best, you will be electrocuted. At worst, fire and death! Get an indicator screwdriver. It costs a penny, but it will save a lot. And the best thing is to call a specialist.
Ivan
The author should be sent to 8th grade. And if he gets his bulb into 2 phases, for example, when a three-phase motor rings, he will be left without eyes. It is necessary to put 2 bulbs of 220 V in the probe, connected in series. And it is desirable to place this probe in a plastic transparent box, or plastic, but with holes. Yes, they will shine less brightly, but safely. And I didn’t even read about nonsense with potatoes. DARKNESS.
Anatoly
Great ways! We should see how you cope with the control in a wooden house without running water and with stove heating
zuruukuk
was it worth it to fence? Everyone should have a penny indicator and more than one! a specialist has one for anyone, and not a non-fua specialist to experiment!
Paul
Likes in any way. Nonsense with a diode. If you do not have an avometer at hand, then there will definitely not be a 1 MΩ resistor. Ilyich's light bulb and wire is the most proven and reliable way. In principle, any electrical appliance is suitable for testing. But not a potato with a resistor for sure. minus 100 likes per post.
Dmitry
It is very important to emphasize!
If any of the listed tests did not show voltage on the core, this does not give 100% certainty that this core is zero!
There can be many reasons for the lack of readings (for example, a break in one of the two half-meter pieces of wire, or poor contact, etc. Conclusion:
Only a test for the PRESENCE of voltage gives a 100% guarantee that this conductor is PHASE. The test for the ZERO wire does not give such a guarantee!
NNK_RTR
I am an electrician (45 years of experience and lived to retire).
It happens that there is no device at hand to check the presence of a phase (and voltage in general)
Method 1: you take the screwdriver with your right hand by the non-conductive handle, touch the tip of the screwdriver with the inside of your index finger, so that when you clench your fist, the finger slips off the tip of the screwdriver. then, alternately touch the wires. The danger of the method depends on the room, floors in the room and shoes. If dry wooden floors, then the method will not work. If the floors are concrete and damp, it will work, only you will no longer be interested in the result.
Method 2: the insulation is removed from the ends of the stranded wire (wire length 1 - 2 meters). Closer to one of the ends, the insulation is removed from the surface of the wire and all the cores are removed, except for one (a fuse is obtained). A nail is hammered into the wall, to which the end, which is closer to the fuse, is screwed. With the other end of the wire, alternately touch the wires. The presence of a phase is determined by a spark. If it is not possible to hammer in a nail, then we are looking for something nearby that is connected with the ground (water pipe, sewerage, grate on the windows, a radiator, fittings in the wall ...). We repeat the steps described in the first method. If the contact with the ground is good, then the fuse will blow (or the standard protection will be knocked out. (Do not forget that the spark can be powerful. When you first touch the wire, close your eyes, If there was no “bang”, then look at the spark (is it there or not )
Valentine
The easiest way is to lick your finger and touch all the wires one by one. Where the phase is, it should splinter a little. (This method does not work if you are standing with wet feet in a puddle)

I am an experienced electrician. I have been working with electricity for thirty years. It happens that they ask me how to distinguish a phase from zero in the absence of instruments. The question is not simple. Now I will try to tell everything that I know about it.

phase and zero. What is the difference?

Strictly speaking, the phase and neutral conductors do not have big differences. In AC circuits, current changes direction fifty times in one second. How can you distinguish what function this or that wire performs? The only difference between the phase and neutral conductors is that the "zero" (neutral conductor) is connected to the Earth. Exactly. An electrical circuit is buried in the ground and one of the transformer leads is connected to this circuit at the substation. Such an electrical circuit is called a network with a deafly grounded neutral. In such a circuit, the neutral wire is at ground potential. We also have the potential of the earth. Therefore, touching a grounded conductor, we do not receive an electric shock.

Now that you have an idea about "zero" let's move on to "phase". The voltage of the phase conductor 50 times per second changes its polarity relative to "zero". In the phase-zero circuit, the current also changes its direction 50 times per second. If the current flows through the human body, it will end very badly. Therefore, exercise extreme caution.

In fact, there is not a single device that would "feel" the "phase". All devices record whether current flows from this particular wire to the "ground" or not. Even a single-pole probe, which is often used to detect phase wires, works on this principle. Now we will not go into the details of how such probes work.

Looking for a "phase"

If we need to distinguish phase from zero, then we must create an electrical circuit with which we will unambiguously know whether the current flows from the wire we have chosen to "ground" or not. A few tools come to mind that can help us:

bulb,
another light bulb, neon,
Light-emitting diode.

There is another way, very unreliable. Recently, wires began to be marked according to the color of the insulation. The neutral wire is blue, the ground wire insulation is yellow-green. But who can guarantee that the electrician made the connection according to the rules or that he was not color blind?

"Grandfather's" way

For decades, electricians have used the light bulb as a measuring instrument. Incandescent lamp, cartridge and two wires. This device was called "control". To determine the "phase", one output of the control panel touched the wire, the other a metal object, which was obviously connected to the ground. It could be the body of the lighting panel, or another switchgear. According to the rules, they are all grounded. Unfortunately, finding a grounded object is not always possible. I met advice when it was proposed to use heating or plumbing pipes as land. I absolutely do not recommend! You can shock an unsuspecting person. Take my word for it. If you are in your own house, in the country, the role of "earth" can be played by a metal pin hammered into the ground, other metal objects that have a reliable connection to the ground.

It is forbidden to use a control box because it can be connected to two phase wires. In this case, the voltage on it will be 1.7 times higher than the mains voltage, the light bulb may simply explode. If you are sure that one of the control wires is connected to the ground, then you should not be afraid of an explosion.

There are safer devices. By chance, an indicator lamp from old communication equipment may be at hand. These light bulbs, "inkas", start to glow if one of the terminals is connected to the phase wire. Single-pole probes are equipped with similar lamps.

A more serious device would be a combination of an LED and a current-limiting resistor connected in series with it. It is clear that this case is for people who are friends with a soldering iron, for example, radio amateurs. The resistor should have a resistance of several tens of kiloohms.

To avoid electric shock, you need to follow one simple rule. During measurements, do not touch the wires and metal with any part of the body.

A digital multimeter is a very useful thing in everyday life. Using a tester, it is easy to determine which of the wires is phase, zero, and which is ground.

Any electrical network, both domestic and industrial, can be with direct current or with alternating current. With a constant supply of electrical voltage, the electrons move in one direction, with a variable supply, this direction constantly changes.

The variable network, in turn, consists of two parts - the working and empty phases. The working voltage, which is called “phase” in electricity, is supplied with a working voltage, but the empty one, which is called “zero”, is not. It is needed to create a closed network for operation and connection of electrical appliances, as well as for grounding the network.

Rules for using the multimeter

To determine the phase and zero using a multimeter, it is necessary to clean the ends of the wires from insulation, separate them in different directions to avoid contact, which will provoke a short circuit, and then apply electrical voltage.

On the multimeter, set the measuring limit of the alternating voltage above 220 V. Insert the voltage probe into the socket marked "V". Touch it to the cleaned core and follow the display. If the value is up to 20V - this is a phase wire, if there is no reading at all - this is zero.

For the correct use of the multimeter, the following rules must be observed:

It is contraindicated to use the device in high humidity.
Failed measuring probes must not be used.
It is forbidden to measure parameters with a value exceeding the upper limit of the measuring instrument.
During the measurement procedure, do not turn the switch and change the limits.

How a multimeter will help find the phase

In order for the multimeter to show which of the wires the phase is in, you need to set the mode on the device to determine the AC voltage, which is denoted as V ~, setting the measurement limit from 500 to 800 V. The probe is connected as standard, black to the “COM” connector, red at VMA.

How the multimeter shows zero

After the wire with the phase has been determined, it is easiest to find the zero one. By setting the red probe to the phase, touch other conductors, after which the tester should show a value of about 220 V. From this it will be clear that the second wire is either zero protective or zero working.

It is very difficult to determine with a multimeter where the zero protective wire is and where the zero worker is, since they duplicate each other. It is best to disconnect the input wire from the ground bus in the electrical panel, then in the checked room there will be no 220 V between the phase and the ground wires, as when checking the phase and zero.

We determine the device ground

The presence of a grounding contact does not mean that this contact is actually grounded. Quite often, this wire is not connected anywhere, but only creates visibility for the user. Competent electricians for the earth choose a wire with a strip, but if the master was inexperienced or negligent in this task, then they might not remember the color marking. In such situations, voltage is best measured by touching water or heating pipes. On a wire with grounding, the voltage level will be less than on zero.

Other verification options

In addition to the listed methods for checking the phase and zero with a multimeter, there is a check using a control lama.
The method is quite unusual and requires special care, but effective.

Such a device requires a cartridge, a lamp, a wire with insulation cut off at the ends. When using a lamp, it will be possible to determine whether there is a phase or not, and which phase conductor cannot be established. If during the connection of the wiring of the test lamp to the conductors to be 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 there is no phase, either phase or zero, which is also possible.

A screwdriver with an indicator to help us

The design of the tool is simple. A light bulb is built in. Sting on one end, shunt contact on the other.

The essence of checking with a control screwdriver is to perform the following actions:

Turn off the power supply from the shield.
Remove the insulation from the cores that need to be checked for 1 cm.
We separate them in different directions to avoid contact.
Apply voltage by turning on the introductory machine.
Bring the tip of the screwdriver to the bare wiring.
If the indicator window lights up during this action, then this is a phase, if it is absent, then it is zero.
Mark the desired core, turn off the automatic box and connect the switching device.

When working with a probe, everyone must follow the safety rules, which consist in the fact that when taking a measurement, you must not touch the screwdriver at the bottom. The tool must be kept clean. Before determining the absence of voltage (as opposed to its presence) in the outlet, you can check the device for serviceability using other electrical equipment that is energized.

By wire color

The simplest and most reliable way to determine the phase and zero is by the color of the wires.
But only if you are sure that the wiring is connected in accordance with all the rules!
Basically, she always lived with a phase of black, brown, white or gray, and zero is blue or blue. It can also be lived in green or yellow-green, this indicates the presence of a conductor with grounding.
In this case, you can do without measuring instruments, according to the color, it is clear where the phase is and where is zero.

When installing electrical wiring, the biggest threat is phase conductors. To prevent a situation that entails a fatal outcome, they are painted in flashy bright colors. This is done so that, under certain circumstances, an electrician from several wires can quickly select the most dangerous and treat them with care.

Content:

When performing repair and construction work, an important stage is the connection of premises and buildings to the power supply system. In this case, in addition to electrical wiring, a large amount of other equipment is installed, including sockets and switches. When making connections, the question often arises of how to determine the phase and zero, as well as the ground conductor in the electrical network. There is no difficulty in solving this problem.

However, simple owners of apartments and private houses without special knowledge and experience often cannot solve this problem on their own. It is possible to determine the purpose of each conductor using several simple and affordable methods.

How to determine the phase and zero with an indicator screwdriver

The simplest and most common way to accurately determine the phase and zero is to use an indicator screwdriver. This operation does not present any difficulties and requires only compliance with a certain algorithm of actions.

When solving the question of how to determine where the phase is and where it is zero, first of all it is necessary to de-energize the line and turn off the machine through which the home electrical network is powered. After disconnecting, strip the wires to be tested, removing about 1-2 cm of insulation. Next, the conductors are separated from each other at a safe distance. This must be done to exclude the possibility of a short circuit in case of accidental contact after applying voltage. After all the preparatory measures, you can begin to determine the phase and zero. First, turn on the machine and apply voltage to the network.

Direct check of the phase and zero by the tester is carried out as follows. The indicator is clamped between the thumb and middle finger. In this case, do not touch the exposed, non-insulated part of the screwdriver tip with your fingers to avoid electric shock.

The index finger should touch the round metal protrusion located at the end of the handle. After that, the tip of the screwdriver is applied to the stripped ends of the conductors. If the tester has touched a phase conductor, the LED lights up in this case. Therefore, the second wire is zero. The neutral wire is determined when the indicator light did not light up initially.

How to determine phase and zero with a multimeter

In addition to an indicator screwdriver, phase and zero determination can be performed using a multimeter. In this case, it is also necessary to strip the conductors to be tested. You must first de-energize the electrical network by turning off the machine. Thus, it is excluded in case of accidental contact of the conductors of the phase and zero. The wires themselves need to be moved apart a little. After that, the machine should be turned on again.

Next, the limit value for measuring AC voltage is set on the multimeter, which is more than 220 V. Then you need to look at what markings the sockets with the probes of the device have. The probe in the COM socket is not suitable for determining the phase, therefore, the remaining probe, marked with the symbol V, will be used. Having decided on the probes, you can begin to determine the purpose of the wires.

You need to take the probe, touch it to one of the wires in the outlet and look at the readings of the multimeter. When displaying data with a small voltage value (less than 20 V), the wire will be considered as a phase wire. If the measuring device shows a zero value, then the wire itself will accordingly be zero.

For measurements, any type of multimeter can be used - with a digital display or pointer. The accuracy of measurements with a multimeter is much higher than with an indicator screwdriver. When determining the phase and zero with a multimeter, it is forbidden to touch the phase and ground wires at the same time. Such actions can cause a short circuit and traumatic burns.

How to determine the phase and zero without instruments

Quite often, situations arise when there is no indicator screwdriver and a multimeter, and you need to find out the purpose of the wires so as not to stop electrical work. In such cases, you have to solve the problem, determining the phase and zero without a device.

The easiest way is to determine the purpose of the wires by their. This technique brings a positive result only when the wiring is done in compliance with all technical rules. In this case, the color of the insulation directly indicates the ownership of a particular wire.

The ground wire is painted yellow-green, and the neutral conductor is most often blue or blue. For the phase conductor, a black, white or brown wire is selected. The correctness of the connection can be checked visually, not only in the shield, but also in junction boxes, at the chandelier and other points.

The second way to determine the phase and zero involves the use of the so-called control light. You can use an ordinary incandescent lamp and two pieces of wire, 50 cm long each. The cores of the wires are connected to the light bulb through and the design is ready for work. One end of the wire needs to touch the heating pipe, and the other end - the wires to be checked. If the light turns on when touched, then this wire is phase.

This method at home is considered dangerous due to the high probability of electric shock. It cannot be used when the voltage limit is present in the network. It is safer to use neon bulbs, which allow you to determine the purpose of the wires with no less accuracy.