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Very often, even the electricians themselves confuse two such concepts as grounding and grounding. How to distinguish them to the average consumer?
By definition, grounding is the forced connection of metal parts of equipment to earth. Its main purpose is to reduce to a minimum the voltage that may occur on the body of the apparatus if an insulation breakdown occurs.

Zeroing is the connection of metal parts of electrical equipment with a neutral wire. If an insulation breakdown occurs and the phase hits the zeroed case, a single-phase short circuit will result. It will cause the voltage to turn off through the circuit breaker.
Zeroing and grounding essentially perform the same task, but in slightly different ways.

How in practice to distinguish the ground conductor from the neutral wire?
Let's say your repair has not been completed to the end and a cable with three cores is sticking out of the socket. It is not so difficult to determine which of them is phase. To do this, use an indicator screwdriver or a tester.

Only by understanding which of the conductors is phase, you can proceed with the methods of finding ground and zero.

1st way to distinguish between grounding and zeroing

To find out where the grounding and zeroing, you must first pay attention to the color coding. If the wiring was done by a competent electrician, then, as a rule, the zero working conductor has Blue colour, and the grounding protective yellow-green.

But do not rely on this 100% and always double-check in other ways:

2nd way

3rd way to distinguish the ground conductor from zero

This method is applicable when a two-pole machine is installed on the input (that is, the machine simultaneously disconnects the phase and neutral conductors):

4th way how to determine grounding and grounding

This method is the least preferred and carries great risks for an inexperienced user of electricity. Therefore, use it last if you have the necessary skills and knowledge.

It is known that electrical energy is generated at power stations using alternating current generators. Then, through power lines from transformer substations, electricity is supplied to consumers. Let us examine in more detail how energy is supplied to the entrances of multi-storey buildings and private houses. This will make it clear even to dummies in electrics what phase, zero and ground are and why they are needed.

Simple explanation

So to start in simple words we will tell you what the phase and neutral wires are, as well as grounding. A phase is a conductor through which the current comes to the consumer. Accordingly, zero serves to ensure that the electric current moves in the opposite direction to the zero circuit. In addition, the purpose of zero in the wiring is to equalize the phase voltage. The grounding wire, also called earth, is not energized and is designed to protect a person from damage. electric shock. You can learn more about it in the corresponding section of the site.

We hope our simple explanation helped to understand what zero, phase and earth are in an electrician. We also recommend that you study in order to understand what color the phase, neutral and ground conductors are!

Delving into the topic

Consumers are fed from the low voltage windings of a step-down transformer, which is the most important component of the operation of a transformer substation. The connection of the substation and subscribers is as follows: a common conductor is supplied to the consumers, extending from the connection point of the transformer windings, called the neutral, along with three conductors, which are the conclusions of the remaining ends of the windings. In simple terms, each of these three conductors is a phase, and the common one is zero.

Between the phases in a three-phase energy system, a voltage occurs, called linear. Its nominal value is 380 V. Let's define the phase voltage - this is the voltage between zero and one of the phases. The nominal value of the phase voltage is 220 V.

An electrical power system in which zero is connected to ground is called a "hard-earthed neutral system." To make it extremely clear even for a beginner in electrical engineering: “ground” in the electric power industry means grounding.

The physical meaning of a solidly grounded neutral is as follows: the windings in the transformer are connected in a "star", while the neutral is grounded. Zero acts as a combined neutral conductor (PEN). This type of connection to the ground is typical for residential buildings belonging to the Soviet construction. Here, in the entrances, the electrical panel on each floor is simply grounded, and a separate connection to the ground is not provided. It is important to know that it is very dangerous to connect the protective and neutral conductor to the shield body at the same time, because there is a possibility that the operating current will pass through zero and its potential will deviate from zero, which means the possibility of electric shock.

The same three phases, as well as separated neutral and protective conductors, are provided from the transformer substation to houses belonging to a later construction. Electric current passes through the working conductor, and the purpose of the protective wire is to connect the conductive parts to the ground loop available at the substation. In this case, in the electrical panels on each floor there is a separate bus for separate connection of the phase, zero and ground. The ground bus has a metal connection with the shield body.

It is known that the load on subscribers should be distributed evenly over all phases. However, it is not possible to predict in advance what power will be consumed by a particular subscriber. Due to the fact that the load current is different in each individual phase, a neutral displacement appears. As a result, there is a potential difference between zero and ground. In the case when the cross section of the neutral conductor is insufficient, the potential difference becomes even greater. If the connection with the neutral conductor is completely lost, then there is a high probability of occurrence emergencies, at which in phases loaded to the limit, the voltage approaches zero, and in unloaded phases, on the contrary, it tends to a value of 380 V. This circumstance leads to a complete breakdown of electrical equipment. At the same time, the body of electrical equipment is energized, dangerous to human health and life. The use of separated neutral and protective wires in this case will help to avoid such accidents and ensure the required level of safety and reliability.

The electrical energy we use is generated by alternators in power plants. They are rotated by the energy of burned fuel (coal, gas) at thermal power plants, falling water at hydroelectric power plants or nuclear decay at nuclear power plants. Electricity reaches us through hundreds of kilometers of power lines, undergoing transformations along the way from one voltage value to another. From the transformer substation it comes to switchboards entrances and further - to the apartment. Or distributed along the line between the private houses of the town or village.

Let's figure out where the concepts of "phase", "zero" and "earth" come from. Substation output element — a step-down transformer, from its low voltage windings, power is supplied to the consumer. The windings are connected in a star inside the transformer, the common point of which ( neutral) is grounded at the transformer substation. It goes to the consumer by a separate conductor. The conductors of the three leads of the other ends of the windings also go to it. These three conductors are called " phases» (L1, L2, L3), and the common conductor is zero(PEN).

Since the neutral conductor is grounded, such a system is called " earthed neutral system". The PEN conductor is called combined neutral conductor. Prior to the publication of the 7th edition of the PUE, zero in this form reached the consumer, which created inconvenience when grounding electrical equipment cases. To do this, they were connected to zero, and this was called zeroing. But the working current also went through zero, and its potential was not always equal to zero, which created the risk of electric shock.

Now two neutral conductors come out of the newly commissioned transformer substations: zero worker(N) and zero protective(RE). Their functions are separated: the load current flows through the working one, and the protective one connects the conductive parts to be grounded with the ground loop of the substation. On power lines extending from it, the neutral protective conductor is additionally connected to the re-grounding circuit of the supports containing surge protection elements. When entering the house, it is connected to the ground loop.

Load voltages and currents in a system with solidly grounded neutral

The voltage between the phases of a three-phase system is called linear, and between phase and working zero - phase. The rated phase voltages are 220 V, and the linear voltages are 380 V. Wires or cables containing all three phases, working and protective zero, pass through the floor shields apartment building. In rural areas, they diverge throughout the village using a self-supporting insulated wire (SIP). If the line contains four aluminum wires on insulators, then three phases and PEN are used. The division into N and PE in this case is carried out for each house individually in the introductory panel.

One phase, working and protective zero, comes to each consumer in the apartment. The consumers of the house are evenly distributed over the phases so that the load is the same. But in practice this does not work out: it is impossible to predict how much power each subscriber will consume. Since the load currents in different phases of the transformer are not the same, a phenomenon occurs called " neutral displacement". Between the "ground" and the neutral conductor, the consumer has a potential difference. It increases if the cross section of the conductor is insufficient or its contact with the neutral terminal of the transformer deteriorates. When communication with the neutral is interrupted, an accident occurs: in the most loaded phases, the voltage tends to zero. In unloaded phases, the voltage becomes close to 380 V, and all equipment fails.

In the event that such a situation occurs conductor PEN, all zeroed cases of shields and electrical appliances are energized. Touching them is life-threatening. Separation of the function of the protective and working conductor avoids electric shock in such a situation.

How to recognize phase and protective conductors

Phase conductors carry a potential with respect to earth equal to 220 V (phase voltage). Touching them is life-threatening. But this is the basis for their recognition. For this, a device called single-pole voltage indicator or indicator. Inside it are a light bulb and a resistor connected in series. When you touch the "phase" with the indicator, the current flows through it and the human body into the ground. The light bulb glows. The resistance of the resistor and the ignition threshold of the light bulb are chosen so that the current is beyond the sensitivity of the human body and is not felt by them.

You can recognize phase conductors by their colors, black, gray, brown, white or red are used for them. The most difficult thing is with old electrical panels: they have conductors of the same color. But the "phase" with the help of the indicator can always be determined without errors.