When working with household electrical networks, you need to know how to find the phase and zero. The usual 220 volts do not come out of nowhere.

The entire low-voltage network (meaning the value, for consumers) is three-phase. The voltage between the phases is variable, 380 volts.

For domestic needs, a voltage of 220 volts is used. In order not to go into the trigonometric details of building three phases, it is enough to know the formula: the voltage between the phase and zero is equal to the voltage between the phases, divided by Square root pi numbers. That is, if there are 380 volts between the phases, then the voltage between the phase and zero will be 380 / 1.73 = 220 volts.

Why is it necessary to know where is zero and where is the phase?

Many users of household appliances believe that there is no difference how to connect electrical appliances to a 220 volt variable network. There is no polarity, the voltage does not change when changing contacts. This is true from the point of view of simply plugging into an outlet.

And if you yourself do the wiring or repair of the electrical network in your house, you need to know exactly where is zero and where is the phase.

1. When designing electrical panels, single-contact machines are used. Only a phase starts on them. The zero line remains unopened. Each line is connected with one wire to the phase through the switch, and directly to the zero line;

Important! If you confuse zero and phase with such a connection, it will be life-threatening to use the network.

2. Lighting devices are powered in the standard way, using single-phase switches. Only the phase wire opens, the zero one is always connected to the light fixture. If you mix up zero and phase, simply replacing a light bulb can lead to electric shock.

Therefore, it is necessary to track the phase and neutral wires along the chain from the meter to each consumer.

Several ways to determine phase and zero

Method number 1, using a tester capable of measuring voltages up to 1000 volts. it reliable way, but for verification it is necessary to have a well-connected ground wire. In the apartments of the old design it is not.

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. One of them of blue color(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 having to touch the dipstick, 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! Online direct current the polarity of the contacts is determined 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.

Electrical networks are of two types. networks alternating current and DC networks. Electric current, as you know, is an ordered movement of electrons. In the case of direct current, they move in the same direction and. as they say, have a constant polarization. In the case of alternating current, the direction of movement of electrons changes all the time, that is, the current has a variable polarization.

The AC network is divided into two components: the working phase and the empty phase. working phase sometimes simply referred to as a phase. The empty one is called zero phase or just zero. It serves to create a continuous electrical network when connecting devices, as well as for grounding the network. And the operating voltage is applied to the phase.

When you turn on the appliance, it does not matter which phase is working and which is empty. But when installing electrical wiring and connecting it to a common house network, this must be known and taken into account. The fact is that the installation of electrical wiring is done either with the help of a two-core cable, or a three-core one. In a two-core, one core is the working phase, the second is zero. In a three-core, the operating voltage is divided into two cores. There are two working phases. The third vein is empty, zero. The common house network is made of a three-core cable. A common or apartment, basically, is also made of a three-core wire. Therefore, before connecting the apartment wiring, it is necessary to determine the working and zero phases.

Methods for determining phase and neutral wires

It is not difficult to find out which core is energized and which is not. There are several ways to determine phase and zero.

First way. Phases are defined according to the color of the shell lived. Typically, the working phases are black, brown or gray, and the zero is light blue. If additional grounding is installed, then its core is green.

In this case, no additional devices are used to determine the phases. Therefore, this method is not very reliable, because when wiring, electricians may not follow the color marking of the cores.

It is more reliable to determine the phases using electric indicator screwdriver. It is a non-conductive housing in which the indicator and are integrated. A neon light is used as an indicator. When the tip of a screwdriver touches a bare, energized wire, the indicator, if the wire is working, lights up. If zero, then it doesn't work. Using such a screwdriver, you can also determine the health of the network. If, when touched with a sting, the wires are alternately wired, the light does not light up, then the network is faulty.

It happens that the indicator lights up when you touch both cores of the wire, that is, both phase and zero. This means that there is a break somewhere in the empty phase. It must be found and eliminated.

It is possible to determine the phase multimeter. First, set the measurement mode - AC voltage. Then we clamp the end of one probe in our hand. With the second probe we touch the core. If the phase is working, then the voltage value will be shown on the screen of the device.

You can determine the working phase and using the usual electric light bulb . We take, screwed into the cartridge, with two pieces of wire. One end is grounded. You can ground it by screwing it to the heating battery. The ends of the wires, of course, should be bare. The second end touches the core. If the lamp lights up, then the phase is working.

One of the methods showing what a phase and zero are in an electrician, on video

Installation of internal wiring, self-installation of switches and sockets is often associated with the need to determine the phase and neutral wires. This process is not complicated if you have an idea about the possible ways and rules for safe work with electricity. We have devoted today's article to the solution of these questions.

First, let's remember a little theory. Everyone knows that for the operation of household electrical appliances, very little is needed - the presence of a voltage of 220 volts in the mains. To supply electricity directly to two (in modern homes - three) wires are used. The first of them is phase, the second is zero and the third is grounding, which protects the user from electric shock in the event of a malfunction in the insulation of the device. Why would an ordinary resident of a high-rise building or country house it is necessary to be able to determine zero and phase?

This knowledge may be needed, for example, when replacing a switch on your own, which is recommended to be installed on a phase wire. This makes it possible to carry out repairs to the lighting fixture without turning off the power throughout the apartment. In addition, installation of an outlet for connecting various household appliances, especially those whose work is associated with the use of running water, as well as those with metal cases. To connect them, in addition to the traditional phase and zero, it is also necessary to use a third wire - grounding.

Phase search by indicator

These days there are several ways to determine the phase without the involvement of a professional electrician. The first of them involves the use of the so-called probe, or phase indicator. It is a narrow flat screwdriver with a plastic handle, which contains a light signaling device - a semiconductor or neon light bulb.

The technology for determining the phase with this device is simple. It is enough just to touch the tip of a screwdriver to the bare wire under study or immerse it in one of the plug holes of the socket.

If there is voltage on the wire or in the socket, the phase screwdriver signaling device will respond with a slight glow. But this will happen only with the correct use of the device - one of the fingers of the hand in which you hold the device must be pressed against the metal end of the handle. In this case, you close the circuit between the wire and the ground, but you should not be afraid of this, since the voltage drops sharply with a screwdriver and will not bring any harm to the user.

Phase detection by tester

The second option for determining the phase wire involves the use of a more advanced device - a tester or multimeter. It allows you to measure various electrical quantities of direct or alternating current. Using the rotary switch, set the device to measure the potential difference of the alternating current. Hold one of the probes of the device tightly in your hand, and with the second touch the wire under test or deepen it into the hole in the socket. In case of contact with the neutral wire, the multimeter display will show a set of zeros or small voltage usually not exceeding two volts. When in contact with the phase conductor, the numbers on the instrument display will be higher.

There is a third option, which can be attributed to the most unreliable. The fact is that at present, according to the rules for the installation of intra-house and industrial electrical networks, all wires have a certain color marking, depending on their purpose. So, a black or brown conductor should be used to connect to the phase, blue or blue to zero, and the grounding conductor is painted partly yellow and partly green.

Unfortunately, the peculiarities of our country and many irresponsible electricians often lead to ignoring the established rules, which can lead to unpleasant consequences. You should not completely rely on the professionalism and skill of the workers involved in the installation of electrical networks in your home. It is better to use the above methods. In addition, until 2011, the wire marking was different from the current one. So, a wire painted black was used for grounding.

Having determined the phase wire, and gently bending it, we proceed to the definition of the neutral wire and the ground wire. The peculiarity of their connection to the in-house shield does not imply the input of a grounding conductor directly into the housing of the input device. In the event that you have access to the shield, you can specify the color of the conductor passing by the machines installed in it and determine its color.

In the event that access to the shield is not possible or, if you wish, to play it safe, you can use the simplest device that any electrician always has - a light bulb with a cartridge and wires attached to it. By connecting or simply touching one of the wires extending from the bulb to the phase wire, short the second wire in turn to the two remaining wires intended for determination. Upon contact with zero, the light should light up. Contact with a ground wire usually has no such effect.

As opposed to the simplest device, you can use the multimeter already described. Alternately measure the potential difference (voltage) between the known phase and the rest of the wires. The value of the zero-phase pair should significantly exceed the value of the phase-to-ground pair.

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When connecting various electrical devices (socket or switch), it is not necessary to take into account the polarity of the conductors. But what if the wiring used in the house is three-core and does not have a color marking, and the devices must be connected with a grounding conductor. To do this, there are several ways to check which of the wires is phase, zero or ground.

Determination of phase and zero without instruments

There are situations when, for the correct connection, it is necessary to find out which wire is the phase and which is zero. For example, to ensure normal operation lighting device, into the gap (through the switch) and the phase wire is det, and the zero one is laid directly to the lighting device. Currently, wiring in houses and apartments is laid with three-core wires, which are divided into three types.

Types of conductors:

• Phase;
• Zero;
• Grounding.

It is possible to distinguish the phase from zero in the wiring visually. But for this, one important condition must be met. Wiring in a house or apartment should be made using multi-colored conductors.

The phase conductor according to the GOST rules must be marked with the following colors: black, white, brown, purple, turquoise, red, gray, pink and orange.

Note! The most common colors found for marking phase wires are white, brown and pink.

The neutral conductor is easy to find, as it is always marked in blue. The ground wire is yellow-green.

It is worth noting that electricity, which is supplied to residential sectors, is variable, so the polarity of connecting electrical appliances does not matter. Proper connection is only important for DC equipment.

Phase and zero in the socket: how to determine with an indicator screwdriver

The easiest way to determine the phase conductor is to use a conventional indicator screwdriver. Currently, there are a huge number of these devices on the market.

Indicator types:

• With neon indicator;
• With the use of LEDs.

indicator using neon light bulb, is made in the form of a dielectric case, inside which there is a neon lamp with a resistor connected to it.

The design of LED indicators is presented in the form of a conventional screwdriver, inside which there is an LED, a microcircuit and several small batteries. These devices, having various characteristics are similar in principle of operation.

It's important to know! It is possible to determine the phase conductor only if there is voltage in the electrical network.

In order to find the phase in the wiring, you must do the following. The voltage is removed from the conductor. This is done by turning off the circuit breaker in the electrical panel.

After that, the wires are stripped of insulation to a length of about 1 - 2 cm. The ends of the wire are parted to the sides, this will help to avoid short circuit between these conductors.

Voltage is applied to the wire by turning on the circuit breaker. Then, the metal part of the indicator is applied in turn to each and wires. The illuminated indicator will indicate the working phase in the wiring.

It should be noted that some devices, due to their design features, can be equipped with a metal plate at the top. To correctly determine the phase conductor, it is not necessary to touch it.

How to find the phase, zero and ground with a multimeter

If the phase conductor is easy to detect using an indicator screwdriver, then it is not possible to determine zero and ground with its help. Since these conductors do not affect the operation of the indicator in any way. In this case, it makes sense to use a multimeter.

To determine you need:

• Multimeter (tester);
• The presence of a voltage of 220 V.

The definition of each of the conductors should begin with the preparation of the device. Probes are connected to the plugs under the name COM and V.

If you need to find a phase wire, then for this, by turning the switch, on the multimeter, you must select the value of the measurement of alternating current in the range of more than 220 volts. After that, the probe that is connected to the socket with the name V, we touch all the conductors in turn. When touching the phase conductor, the display of the device will show values ​​​​from 8 to 15 Volts. The neutral and ground conductor will not change these readings.

Note! When working on energized wiring, be sure to follow the safety rules.

After the phase conductor is found, you can start searching for the zero one. To do this, with any probe of the multimeter we touch the phase conductor, with the other we close the contact with any of the other conductors. The neutral conductor will be indicated by the value of 220 Volts that appears on the display of the device.

The third conductor will be the ground conductor. The readings on the display when touching the phase and ground wires are always lower than 220V.

Non-standard ways: how to determine the phase in the wiring

It should be borne in mind that these methods are unsafe. It is recommended to use them only if all necessary safety measures are observed.

Definition methods:

• Homemade control light;
• Potato.

To make a control light, you will need an ordinary cartridge, an incandescent lamp of any fashion and a meter wire. First of all, we clean the wire from insulation by about 1 cm. Next, we disassemble the cartridge and connect the ends of the wire to its terminals.

Then, in order not to damage the light bulb, it is necessary to strip the remaining ends of the wire to a length of 3 cm. We screw the light bulb into the prepared device. After that, turning off the voltage, we clean the ends of the conductor on which it is necessary to find the phase wire.

It is not necessary to twist the contacts of the control bulb with the wire, since free access to the conductor contacts is required.

Next, using any metal object, we clean a small area on metal surface water pipe. We apply voltage to the conductor and with one contact of the control we touch the stripped area on the pipe, and with the second one of the contacts of the wire. When touching the phase conductor, the lamp will light up.

Using a potato, check which of the phase wires is presented as follows. The device will require two meter-long wires and a 1 mΩ resistor. One of the wires must be mounted in a potato and attached to the pipe. The other wire is mounted in a potato with one of the ends, and the phase wire is searched for with the other. The appearance of browning on the potato will indicate the phase wire.

Understanding how to determine the phase and zero (video)

As practice shows, in most cases, the search for phase and neutral conductors in the AC electrical network is not necessary, since the polarity does not matter when connecting various household devices.