The digital multimeter is very useful thing at home. 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 cores from insulation, separate them into different sides to avoid contact, which will provoke a short circuit, and apply an electrical voltage.

Set the measuring limit on the multimeter AC voltage above 220 V. Insert a 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 voltage alternating current, which is designated as V~, setting the measurement limit from 500 to 800 V. The probe is connected as standard, black to the “COM” connector, red to “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 from the ground bus in electrical panel input wire, then in the tested room between the phase and the ground wires there will be no 220 V, 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 neglected 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 in a reliable way determining 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. May also be lived Green colour 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.

To successfully start work related to electricity and determine the phase and zero in the conductors, we will prepare the necessary devices and devices for this:

• digital or its analog analogue;
• tester (can be replaced with an indicator screwdriver);
• felt-tip pen;
• pliers, side cutters;
• insulating stripper (tool for removing insulation from wires);

In addition, the location of protective equipment should be determined: automatic network de-energization devices or plugs,. Their standard location is on the site, near the apartment and inside. In order to maintain safety, we carry out manipulations with electrical appliances and bare wires by first turning off the machine.

Phase and zero measurements with a multimeter

In everyday life, electrical networks are used for 3 phases, supplying a current of 380 V to the consumer panel. In houses, wires with a voltage of 220 V are mainly wired, because they are connected to zero and one of the phases. Properly installed wiring is grounded.

Measurement of voltage between conductors is carried out with a multimeter. Before starting measurements, we set the device to the maximum possible alternating current value with the “~V” or “ACV” sign and a value exceeding 250 V (as a rule, digital devices are set to 650-900 V).

Measuring contacts simultaneously touch 2 conductors and measure the voltage. Voltage fluctuation in household networks is +/-10% of 220 V.

You should be extremely careful about the settings of the device, since upon contact with the phase and zero, with the settings set to measure the resistance indicator, the wiring will close and, most likely, injuries and burns will be received.

Definition by external examination

Wiring installed in compliance with all requirements can be distinguished by the color of the wires per phase and zero. It is simply recognized that the ground wire, which has a yellow-green color, the sheath of blue or of blue color is the null conductor. Black, white or brown - in such insulations, the sheath of the phase wire is made. Thus, it is checked for correctness of the connected connections.

After checking in the instrument panel that the wires are connected to their color marking, you can proceed to inspect all junction boxes. Pay attention to twists. The neutral and ground wires are not twisted together, we look at the color to see if this is the case.

If to phase in junction box switches are connected, then basically their installation is carried out with a two-wire wire having insulation colors, for example, white-blue and white. This is not something out of the ordinary and is not uncommon.

In the case of installation in the appropriate color combinations of conductors, then we check the phase wire, using an indicator screwdriver for this.

Using a screwdriver with indication

Often, in old houses, wiring is done without a ground wire. In this case, it remains to determine only the phase. This can be easily done with a screwdriver. This measurement is based on the fact that inside the device contains a light bulb and a resistor (resistance).

In the event of a short circuit electrical circuit, the signal flashes. The resistance provided in the screwdriver with indication is designed to carry out measurements safely for humans, lowering the current to non-critical values.

Preparation before using the indicator: the automatic plug on the electric meter is turned off, then we clean the conductors with a knife for a length of 10-15 mm. The ends of the wires are separated by a certain distance to prevent their accidental contact.

Switch the machine to the working position and apply a screwdriver with indication to the stripped conductors in sequence. Once on the phase wire, unlike the zero one, the signal diode will light up. The detected phase must be marked with electrical tape or a felt-tip pen, in order to make further connections, which should be started with the machine turned off.

When lighting fixtures are being installed and the switch has contact with the phase conductor, it is not necessary to turn off the machine to replace the burned-out lamp.

When testing the wiring, the indicator screwdriver is held in the hand in a certain way: the screwdriver is clamped between the middle and thumb fingers, without touching the bare metal. At the end of the handle is a metal washer, put your index finger on it. Next, we test.

Incandescent lamp application

This is a method of using an incandescent light bulb to identify the conductors of the corresponding color in a 3-conductor network. This method provides for increased security measures.

To apply this method, an ordinary incandescent lamp is screwed into the cartridge. Wires that do not have insulation at the ends are screwed onto the cartridge.

If a kit is not available for this method, a standard table lamp can be used. In this case, in order to get the result, you should alternately, by color, connect the conductors to the plug.

The disadvantage of this method is that by applying it, it will be impossible to know for sure which of the two phase conductors. That is, by this method, we rather check the system for operability.

And the advantage is that with a high degree of probability we will know the following: 1 wire is zero, the other wire is phase. If the light is off during testing, this indicates the absence of a phase in the tested conductors.

Measurement of the resistance of the "phase-zero ring"

For planned control and timely detection and elimination of security violations in the power supply network to ensure its normal operation, systematic measurements of the resistance of the phase-zero ring are carried out, since the causes of breakdowns in lighting devices are network overloads and short circuits.

The fastest and effective method detecting and preventing such cases is the measurement of resistance.

Not everyone knows what the concept of "phase-zero ring" means. It means a circuit created by connecting a neutral conductor located in a grounded neutral. The closure of this electrical network forms a phase-zero ring.

The resistance in the circuit is measured:

1. voltage drop off circuit.
2. voltage drop due to increasing load resistance.

1. Inspection for mechanical damage, the wire should be carried out starting from the point of exit from the walls, it is there that it usually breaks.
2. All current-carrying parts of conductors must have reliable insulation, and socket contacts are mounted in the housing so that they cannot be accidentally touched by open areas of the body.
3. For home use it is quite enough to get a control lamp and a screwdriver with indication, their cost is not significant. For a person experienced in electricity, a more expensive device, a multimeter, is suitable, as it has a wide range of measured values.

You can check the functionality of the electrical network in an apartment or a private house different ways. From a financial point of view, the best option would 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 tip, it is needed to lower the current strength to a safe one for human body quantities;
• then there is an LED that is connected to the contact patch brought to the end of the screwdriver;
• The case is made of transparent plastic, this allows you to see the LED light up.

Phase and zero in a screwdriver

Find phase and zero indicator screwdriver won't be 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 mains is AC, 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 will be able to give the maximum amount of 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 taking measurements 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, problems and malfunctions arise in any electrical system. These problems are not always worth inviting an experienced electrician; some breakdowns can be fixed on your own. However, in order to be able to find a malfunction in the network, you will definitely need a special tool, which costs, purchase in advance.

As you know, the electricity that is supplied to our house is three-phase. The voltage between any two outputs is 380 V. At the same time, we know that the voltage used in household appliances is 220 V. How is one converted to the other?

The neutral wire plays an important role here. If you measure the voltage between one of the phases and this wire, then it will just be equal to 220 V. In more modern sockets, an additional zero output is provided - this is the so-called protective zero.

A natural question arises as to what is the difference between the two mentioned zeros? The first of them, “working zero” (we are trying to determine it) is a neutral contact on a three-phase installation of a generating substation, connected to a neutral contact of a three-phase installation in a house or a separate entrance.

He may not be grounded at all. The main purpose is to create a closed electrical circuit when powering household appliances. In the second case, we are talking about. It is commonly referred to as "protective earth".

Due to the rather complex nature of alternating current, there are some typical views on the neutral wire and on the ground, which may not correspond to the real state of affairs:

1. “There is no voltage at zero at all.” This is not true. It is connected to the zero connector at the substation and is designed to create a potential difference at the output. Sometimes he is under pressure.
2. "If there is grounding, then short circuit definitely won't." In most cases, it is. But if the current rises too quickly, it may not have time to leave through the ground in time.
3. “If two cores in the cable are the same, and the third is different, then this is probably the ground.” It should be, but sometimes it isn't.

Methods for determining

Digital multimeter

Determination of zero and phase by using a multimeter. This device is very useful for working with electricity. It includes various features. It can be both an ammeter and a voltmeter or an ohmmeter.

Also, depending on the specific type, there may be other possibilities (for example, frequency measurement). These devices can be either analog or digital.

Using an indicator screwdriver. This screwdriver has a transparent handle. If you insert it into the outlet in a certain way, then when it hits the phase, the light will turn on.

There are several designs of such screwdrivers. In the simplest case, when testing, you need to touch the end of the pen. Without this, the flame will not light up.

With visual testing, the purpose of the wires can be determined by their colors.

Using a special phase. This is a small digital device that fits in the palm of your hand. One of the wires must be held in hand, the other is checked for phase.

Step by step instructions

Let's talk in more detail about how to produce such work.

When using a multimeter, you need to correctly set its operating range. It should be 220 V for AC voltage.

It can be used to solve two problems:

1. Determine where the phase is, and where is the "working zero" or grounding.
2. Determine where, in fact, grounding, and where is the zero output.

Let's talk about how to complete the first task first. Before starting, you need to correctly set the operating range of the device. Let's make it more than 220 V. Two probes are connected to the "COM" and "V" sockets.

We take the second of them and touch the outlet hole to be tested. If there is a phase, then the multimeter will display small voltage. If the phase is not there, then zero voltage will be shown.

In the second case, the operating voltage should be 220V. We insert one wire where there is a phase. We test others with others. When it hits the ground, exactly 220 V will be shown, otherwise, the voltage will be slightly less.

Using a phase tester

We hold one wire neatly with our fingers, we use the other for testing. If we hit the phase in the outlet, then the numbers on the indicator will be much greater than zero. When hitting zero, the screen will also show zero or a small amount of voltage.

This device is convenient both because it is generally available on the radio measuring equipment market, and because the measurements are made with a sufficiently high accuracy.

Using an indicator screwdriver

It looks like an ordinary screwdriver, but with a slight difference. It has a transparent handle with a small light bulb inside. This, at first glance, a rather primitive device, is actually very convenient.

It is enough to simply insert it into the outlet hole, while touching the opposite end of the screwdriver with your finger. If there is a phase, then the light will light up. If there is a neutral wire or ground, then it will not burn. It is important to remember that it is strictly forbidden to touch the metal part of the screwdriver during the measurement process. This may result in electric shock.

In some cases, the phase and neutral wire can be determined without any instruments or fixtures. This can be done if you read the label correctly. This is not a reliable method, but in some cases it can be useful.

When working in modern homes, the rules for such labeling are usually followed.

So what are they:

1. The wire where the phase is, usually brown or black in color.
2. Null, It is customary to designate a wire that has a blue color.
3. Green or yellow the wire that is used for grounding is indicated.

These rules may have been different in previous time periods. Also, they may change in the future. Therefore, the described method is suitable only for preliminary testing of the purpose of the wires.

How to distinguish between grounding and neutral wire when the phase is off?

Assume that there is no current in the network. Is there any difference in this case between ground and neutral wire? At first glance, it may seem that they are very similar to each other.

In fact, their functions are still different. Grounding is intended for emergencies. Through it, the electric charge goes to the ground. The neutral wire is part of the electrical circuit for power household electrical appliances in the house.

Here, current, unlike grounding, is present. How can you tell them apart? With the phase off, you just need to measure the current between this wire and a known ground. If this is a neutral wire, then the current, although small, will be in this case. If there is grounding, then there can be no current here.

In what cases may be needed?

With a huge variety of existing electrical appliances, there is a difference in what kind of electrical power they need. In different cases, such issues are resolved in different ways.

Sometimes, special devices are used for this - adapters. In some cases, it is only necessary to make the right connection to the outlet. In particular, when connecting an electric stove, there is a need to correctly determine when connecting where the phase is in the outlet, and where is the “working zero”.

In this, and in similar cases, it is impossible to do without such information.

Another situation where it is necessary is various kinds of repair work. When conducting them, you need to know exactly which wire is energized (it must either be disconnected or securely insulated), and which one is not.

When connecting many household appliances, it really doesn’t matter which side the phase is on, but for the switch it may matter. Let's explain this. "Phase" should be fed to the switch, and "zero" let it be connected directly to the lamps in the chandelier.

At the same time, in the process of replacing the lamp in the chandelier, with the switch turned off, a person will not be shocked even if he accidentally touches it.

To understand what phase and zero are in a socket, ordinary person(not a specialist) there is no need to delve into the electrical jungle. As an example, let's take an ordinary power outlet that receives alternating current.

Two electrical wires go to the outlet - zero and phase. The current flows only through one of them - the phase one (it is also called the working phase). The second wire is zero (or zero phase).

Zero and phase in old sockets

To connect the old outlet, use two conductors. Some of them are blue (working neutral conductor). This wire carries current from the power source to the appliance. If you take hold of a current-carrying wire, but do not touch the second wire, electric shock will not occur.

The second wire in the socket is phase. He happens to be the most different colors, including blue, green-yellow or light blue.

Note! Any voltage exceeding 50 volts is life-threatening.

Phase and zero in a modern outlet

There are three wires in modern type devices. Phase can be any color. In addition to phase and zero, there is one more wire (protective zero). The color of this conductor is green or yellow.

Voltage is applied through the phase. Zero is used for protective zeroing. The third wire is needed as additional protection- to take excess current during a short circuit. The current is redirected to the ground or in the opposite direction - to the source of electricity.

Note! It does not matter in practice whether the phase and zero are located on the right or on the left. However, most often the phase is located on the left, and zero is on the right.

Determination of phase and zero with a multimeter or screwdriver

multimeter

The device is a combined electrical measuring device capable of performing several functions. The minimum equipment includes a voltmeter, an ohmmeter and an ammeter. Separate modifications are made in the form of current clamps. Both analog and electronic meters are available.

To start the measurement process, switch to AC voltage measurement mode. Measurement is carried out by one of several methods:

1. We clamp one of the available probes with two fingers. We direct the second probe to the contact, which is located in the switch or socket. If the data on the monitor is insignificant (does not exceed 10 volts), we are talking about zero. If you touch another contact, the indicator will be higher - this is a phase.
2. If there are concerns about the need to touch the probe, there is another way. We send one of the rods to the outlet. With the second rod we touch directly to the wall next to the outlet. The result will be approximately the same as in the case described above.
3. There is a third way to measure with a multimeter. We touch the probe to a grounded surface (for example, the equipment case). Touch the surface to be measured with the second probe. If the wire is a phase, the multitester will detect 220 volts.

An indicator is a simple way to determine the phase, accessible even to a person who has taken up this business for the first time. The control screwdriver looks like a standard one. The difference lies in the presence of an internal device in indicator screwdriver. The screwdriver handle is made of special transparent plastic. Inside is a diode. The top part is made of metal.

Note! Do not use the indicator screwdriver for other purposes. It is not intended for unscrewing and tightening screws. Misuse of the control screwdriver will cause it to fail.

To find the phase and zero with a screwdriver, you need to perform the following sequence of operations:

1. Touch the contact with the end of the screwdriver.
2. Press your finger on the metal button at the top of the screwdriver.
3. If the LED lights up, it is a phase. If he doesn't respond, it's zero.

Note! An indicator lamp rated for 220-380 volts will glow at voltages greater than 50 volts.

1. Do not touch the lower end of the screwdriver while measuring.
2. Keep the screwdriver clean, otherwise there is a risk of breaking the insulation.
3. If you need to determine the absence of voltage, first check the performance of the device, which is definitely under voltage.

Advice! In a DC network, the polarity of the contacts is determined by a very in a simple way. To do this, simply lower the wires into a container of water. Bubbles will form near one of the wires - this is a minus. The second wire is positive.

Do not confuse an indicator screwdriver with a ringing device. The chime screwdriver is supplied with batteries. When working with such a device to determine zero and phase, you do not need to press the button, since the screwdriver will glow in any of the possible situations.