How to connect the neutral wire in the panel

Installing an electrical panel with your own hands with minimal knowledge about wiring and electricity is a very real task. You just need to carefully and thoroughly study the instructions for connecting the machines in the switchgear and do everything strictly in accordance with it.

The worst thing that can happen if the wires are wired incorrectly is a short circuit, which can lead to the most undesirable consequences. In theory, a common circuit breaker, which should be in the circuit earlier than the mounted panel, should eliminate these consequences.

If we are talking about a floor panel in a city residential building or an individual one located in an apartment, then a circuit breaker will be a faithful protector. It can be a three-phase switch or a single-phase one - it all depends on the wiring diagram in the house.

Everything becomes more complicated when working with the wiring of a private house. In this situation, you must be protected by a machine located in the transformer booth from which the line is extended to you. Sometimes there are intermediate transformers that can be seen on power transmission towers in rural areas. They are often supplemented with protective fuses that prevent the transformer from failing when accidents occur on the line.

But if you know exactly the rules for connecting the machine in the control panel, you can avoid emergency situations. In this case, you have the only unpleasant and somewhat dangerous job - connecting the assembled device “hot”, that is, to live wires. Or you will need to call an electrician who will remove the voltage from the line during installation.

But first, let's look at the installation and connection stages.

Grounding device

In many ways, the electrical circuit of the floor panel depends on the house itself. As a rule, in a private house, if there are no plans to connect such powerful devices as three-phase boilers, then a single-phase line is installed. These are two wires: zero and phase. In internal wiring, it is customary to wire the phase wire with a conductor in brown insulation, and the neutral wire with blue insulation.

If the wire is three-core, then the third wire is usually painted yellow with a green stripe. This bright conductor is used for grounding. It is never put into the machine inside the shield. The grounding conductor must be continuous, therefore, in switchgears, special conductive blocks are used, which are installed next to the machines in order to pass the grounding conductor through them and safely bring it to the floor where it is connected to the grounding bus. As a rule, this is either the first floor, or the basement, or the basement.

Grounding

With the help of a grounding loop, the potential of the protective PE conductor, and therefore the housing of all equipment connected to the electrical circuit, will be equal to the ground potential. This is why it is important to monitor the resistance of the ground circuit. According to the rules, it should not exceed 4 ohms. The grounding device diagram is shown in Fig. 2. Grounding consists of a grounding conductor and a grounding conductor.

Figure 3. Grounding device diagram

A ground electrode is a metal conductor in direct contact with the ground. A grounding conductor is a metal conductor that connects the PE bus of the input panel to the ground electrode.

How to connect the phase and neutral wires

Connecting the phase conductor to the machine is mandatory. The neutral conductor does not always have to pass through the machine, but there are cases when it is recommended to use a two-pole automatic switch, and then both phase and neutral pass through it - each wire through its own section.

Simultaneous disconnection of phase and neutral is justified especially in situations where three-phase voltage is introduced into a house or non-residential building. In such situations, there is a greater risk that one of the phases may short circuit to zero. This is a short circuit mode to which the machine protecting this phase must respond. But in those fractions of a second while it is triggered, an overvoltage will occur in the other two phases. That is, instead of the required 220 V, there may be all 380 V - the voltage difference between the two phases with a conventional three-phase connection.

Not a single household appliance is designed for such voltage, and the more powerful it is, the more current it passes, and the greater the likelihood of it burning out due to overvoltage. Where the fuse of a low-power device immediately blows, powerful equipment will still “tolerate” a heavy load for some time, and during this time the switching power supply or transformer may fail. Therefore, it is preferable to protect equipment such as boilers, dishwashers and washing machines with two-pole circuit breakers that cut two circuits at once.

Keep in mind that phase imbalance is also harmful to the source that powers the building. A generator, a transformer booth, a substation - all this will deteriorate very soon. For such purposes, there are special three-phase circuit breakers, which, in the event of a large imbalance or failure in one of the phases, can immediately turn off all three phases simultaneously. For more critical circuits, it is recommended to connect a four-phase circuit breaker, which also de-energizes the neutral wire.

Zeroing

According to the Rules el. safety, zeroing is called: “…. connection of the equipment housing with the neutral protective conductor.” Now let's reason. We have an electrical appliance (say, a washing machine) that needs to be grounded. The machine's plug and socket are three-pin, but the wiring is two-wire, which means we have no grounding. But we know that the “zero” at the substation is grounded, so why not connect the “zero” and “ground” contacts in the socket? In no case!

Let’s read the wording again: “...zero protective conductor.” That's the point! After all, the “zero” in the socket is a working conductor, not a protective one, and you cannot install a jumper between ground and zero in the socket:

this may result in a short circuit;
b)
if the zero has a poor contact, the phase through the device will go to the neutral of the socket, and through the jumper and ground wire to the body of the device.

We read the rules further: “Grounding is intended to eliminate the danger of electric shock in the event of a short circuit to the housing... in three-phase four-wire networks...”. But in the apartment the network is single-phase! In a multi-storey building, the network is three-phase, four-wire, so grounding can be done no closer than in the distribution cabinet of the house.

Installation of a panel with automatic machines

So, let's look at several options.

First option. It is necessary to make a device in a house where all three phases are connected. Most of these are houses with elevators. Professional electricians recommend using all three phases for different apartments. Therefore, the input machine will be three-phase. As a rule, introductory machines are usually installed in the panel at the top left. From it the wires will already be distributed to apartment automatic machines. In the case when three apartments are connected to the switchboard, it is best to power each apartment with its own phase: this way there will be no risk of overloading any of the shoulders. Next, you need to find out what kind of electrical connection is in each of the apartments.
The second option is division by premises. In older homes, wiring was usually divided into two parts: lighting and outlets. Consequently, only two machines were used for each apartment.

In modern houses, they try to install a two-phase machine or at least a separate single-phase one for “power equipment”. The equipment, in turn, can be divided into the following categories:

washing machines;
dishwashers;
electric stoves;
other powerful household appliances.

To do this, a separate wire is connected to the device, which usually contains zero, phase and ground. That is, for each apartment there are three machines and one grounding conductor. Single-pole circuit breakers are used for sockets and lighting, so the zero will have to be connected to special blocks.

For example, we can consider a single-pole connection option. What does it mean? That is, only a phase will pass through the circuit breaker. Such a machine has one contact for phase input, the other for output. As you know, the input contact is located at the top, while the output contact is at the bottom.

Before connecting, you need to make sure by the marking near the top contact that it is really intended for the power conductor. To connect this wire, it must have brown or black insulation; it must be stripped of this insulation by 7–10 mm. The wire is inserted into the hole in the upper end of the machine and clamped with a screw located on the front of the case.

The outgoing wire is attached in the same way from the bottom end. This is exactly the wire that goes into the apartment. Here, too, it is important to monitor the markings of the conductors so that it does not turn out that the switch at the chandelier will interrupt zero and not phase. That is, the conductor coming out of the machine should not be zero for the apartment. While the apartment is de-energized, you can open the nearest switch and ring the wire from it with a tester before entering the apartment. If the tester shows conductivity, then this wire inside your apartment is wired as a phase wire.

However, connecting the machine in the panel may be fraught with another pitfall: if there is not one phase, but at least two, separated on the floor, then you must not confuse them, so that in the apartment there is no difference of 380 V between the sockets and chandeliers! No matter how many machines there are in an apartment, everything must be connected to the same phase.

Grounding in an apartment

The most reliable way to protect against electric shock in everyday life is through electrical appliances. After all, many of our home assistants have metal (read: conductive) cases, and as a result of a break or damage to the insulation, the phase wire may touch the body of the device. And then touching him becomes deadly...

To avoid trouble, the body of the device is connected to the ground. Now, when a phase hits the housing, a short circuit occurs and the protection is triggered, cutting off the current supply.

In modern apartments it is performed according to a three-wire circuit:

Phase; zero; Earth.

Grounding of electrical appliances occurs through the third contact of the plug and. The situation is more complicated in houses where it is installed using a two-wire circuit, and there is no ground wire in the sockets. In this case, the grounding wire will have to be drawn directly from the device body.

Where can I get “land” in an apartment in a multi-story building? The answer is simple: in the electrical panel installed on each floor.

Before performing this (it is better, of course, to do this with the participation or supervision of a professional electrician), carefully examine the electrical panel. After all, if there is no reliable grounding at the switchboard, connecting the apartment’s grounding wire to it is not only in vain, but also dangerous!

Let's explain with an example. The neighbor has a short circuit. The current will travel the following path: the neighbor’s phase – the neighbor’s “zero” – the floor electrical panel – your ground wire – the body of your device!

Wiring

Experienced electricians use a little trick when they need to connect several machines and not make a mistake with the introductory phase. To do this, you need to take one conductor and strip not only its end, but also make intermediate stripped places in such a way that each of them can reach the contact of the machine.

Ideally, if the machines are located next to each other on a DIN rail, then these distances can be measured simply by attaching a conductor so that the transition part from one machine to another forms a loop. This will allow the wire to exit the housing vertically.

The stripped area should be twice as long as the end of the wire, because we will have to make a small loop out of it, which will be used to connect the machine. You will need to put heat-shrink tubing on this loop or tightly wrap it with electrical tape at the place where the insulation ends. This will give our wire rigidity.

Then the loop must be inserted into the contact hole of the machine and tightened tightly. The cleaned areas should correspond to the number of circuit breakers. But we will be sure that the phase is separated correctly - the same for the apartment.

How to get electricity from the ground

Since the soil contains both electricity and electrolytes, it can be considered not only as an environment for living organisms and a source of crops, but also as a mini power plant. In addition, our electrified homes concentrate in the environment around them the electricity that “drains” through grounding. You can't help but take advantage of this.

Most often, homeowners use the following methods to extract electricity from the soil located around the house.

Traditional sources

The most pressing question for owners of country houses and summer cottages will be the source of electricity (

A little about mechanics

Having dealt with the question of how to properly connect the machine, the question of how to install it remained unexamined. If you are planning a new shield, then most likely the first thing you will have to do is install a DIN rail there.

Each modern circuit breaker has a special clamp for mounting on this very rail. The feed-through contact, which is used for the grounding conductor, has the same fastening. By the way, the latch of such a grounding conductor is not made as a separate plastic element, but as a springy part of the housing. This is very convenient, as there is no risk of losing a small but very important detail.

If it is not possible to find a pass-through element, the grounding connection can also be made by twisting. However, to be sure, you can tin the wires with a soldering iron and put heat-shrink tubing on them as insulation. This is completely justified. Do not forget that phase and neutral conductors still “walk” along the shields. If you don't have heat shrink tubing, you can use insulating tape. This will be no less protection against any surprises.

By the way, it is strictly worth remembering that the connection and even grounding cannot be done in such a way as to twist copper and aluminum wires together. These two metals form a galvanic couple, which leads to their oxidation and disruption of conductivity between them. If it turns out that it is not possible to connect them through a pass-through element or a block with steel contacts, then you can tin each of the wires and carefully solder the connection.

Importance of the issue

If you are wondering whether it is necessary to do grounding in your country house or cottage, then we immediately say that you cannot do without a protective circuit. Even according to the standards of PUE, SNiP and GOST, it is necessary to make a special outlet that will protect you from electric shock. The organization of the TN-S system (its correct name) in a 220 and 380 Volt network must be done during construction, because then it will be more expensive to do this (it will be necessary to change the two-core cable to a three- or five-core cable throughout the house).

If you purchased a house that does not have grounding, then you need to install and connect it. Installation of the grounding system is quite simple. In addition to grounding, it is necessary to create lightning protection. We talked about how to make a lightning rod with your own hands in a separate article.

Hot work

There are often cases and situations where work on connecting machines is performed in force majeure situations. An excellent example of such a current situation is the burnout or failure of the machine. Often it is necessary to connect a new circuit breaker when the panel is energized. What do you need to know for such work?

The first rule is not to panic and take your time.
The second rule is to use a special indicator screwdriver.

Let's look at everything in detail. If it is not possible to turn off the access panel, then from the “affected” machine, then you need to perform the following steps:

Remove the power, that is, unhook the input wire from it.
Wear sunglasses to protect your eyes from sparks and electrical protective rubber gloves.
Arm yourself with an indicator screwdriver and a regular screwdriver with an insulating handle.
On short-sleeved clothing, wear something with long sleeves over it.
Now, carefully, without touching any metal objects in the shield, since in the event of an accident the phase may “sit” on them, unscrew the input contact screw with one hand, and with the other hand remove and bend the wire so that it does not touch any metal surface.

It is prohibited to take this wire by its exposed part!

Sparking during such a shutdown is normal. The wire just needs to be pulled away from the contact confidently and quickly to a distance that cannot be penetrated by a spark.

Before connecting anything, you need to take an indicator screwdriver and examine the parts of the switchboard related to the apartment for the presence of voltage. If it is not there, then you can install and connect a new machine.

If several phases enter the switchgear, of course they can also be disconnected. However, this will result in you leaving your neighbors without electricity. Therefore, connecting a new circuit breaker will have to be done with an eye to the fact that there is one or two more phases in the panel.

Shorting the supply conductor, which you so skillfully disconnected from the damaged machine, with any other phase or with zero will lead to overvoltage and a real fireworks of sparks, from which clothing and glasses should be protected, just in case.

Grounding and grounding schemes

These protection schemes must be used very carefully. First of all, this is due to the uneven distribution of loads on the phases

With the same load on each, a small current will flow through the common neutral wire. However, if only one phase out of three is loaded, then the current value in the neutral wire will be the same as in this phase.

It is not recommended to do grounding in residential buildings. As a rule, neutral conductors have a smaller cross-section than phase lines. The neutral wire is very often left uncontrolled, its connection gradually weakens, and oxidation occurs. When heated too much, it simply burns off. In this situation, the phase directly hits the shield. Through grounding, current enters the apartment and disables all grounded equipment. Household appliances are energized, which increases the risk of electric shock.

Thus, it is undesirable to use grounding in residential buildings. Typically, it is used in industrial enterprises, where the phase load distribution is more uniform, and the neutral wire performs a protection function.

Why do you need a partner?

As you know, when working with electricity you need to take as many safety precautions as possible. Another practical advice from experts is to repair electrical wires with a partner.

The person chosen for this role may well not understand anything about electrical circuits. However, he must clearly know what to do if someone comes under voltage: pull the person by the clothes, without touching his body, away from the live wire.

It is advisable to first unbutton the jacket that you are wearing to protect your hands before making connections in the electrical panel. This is vital. The fact is that a free part is formed on the back, by which a person can be pulled away in the event of an electric shock. It will be convenient for your partner to grab onto it. Your partner should also remember how to call an ambulance or emergency services.

The help of a partner can be invaluable when the shield is located high. He will be able to give or receive tools. This way, you won’t have to constantly go down and get up again from a stool or stepladder.

Safety first

Summarizing all of the above, it must be said that you should never forget about safety when working with electricity. Neglecting at least one of them can lead to serious health problems and sometimes death.

A person who is poorly insulated from the ground can get an electric shock when touching a phase. Electricity will pass through the entire body and go into the ground. There are quite frequent cases when a person dies from exposure to current passing through the heart.

The grounding conductor is safe and can be safely handled. But even here you need to do this with caution and check it in advance for breaks in the wiring and electrical panel.

That is why it is vital to purchase protective clothing, rubberized tools and use insulating materials for working with electrical wires.

But first, let's look at the installation and connection stages.

What happens if you confuse zero with ground?

In this case, frequent operation of the RCD is observed. If the device is not present, there is a potential for danger to humans.

The operation of the devices will not be affected, and the consumer will not feel the difference. Residents of other apartments connected to the same power line will be at risk.

If the ground and zero are connected incorrectly, the following problems may occur:

fine for illegal penetration into the network;
breakdown of electrical appliances, including those located in neighboring apartments;
the appearance of voltage on the grounding contacts.

Therefore, it is necessary to promptly solve the problem of the lack of zero in the electrical wiring. If the “working 0” supplied to the outlet is damaged, you need to look for the break point in the apartment. Instead of a failed zero, you can use grounding, but not vice versa.

The cables need to be re-labeled:

in sockets;
on the zero line;
in the shield.

Powerful household appliances are connected to different branches. Each line is equipped with its own emergency switch.

The RCD can be common to the entire electrical network. It is allowed to connect the grounding wire of another branch.

Grounding device

We prepare tools and materials

As for the tools for installing grounding in a country house (for example, in a country house), you will need:

a welding machine (its presence is required, since connecting plates and reinforcement without welding will not create high-quality contact, especially under the soil);
grinder (cut metal into suitable pieces);
bayonet shovel;
perforator;
sledgehammer (the heavier the better, because you will have to drive the pins 2 meters deep);
set of wrenches (tighten the bolt).

If you have at least some electrician skills, we recommend making a welding machine yourself! There is nothing complicated about it!

Materials to be used:

Metal corner made of stainless steel with dimensions 50*50 mm, length of at least 2 meters. An alternative option is a steel water pipe with a diameter of 32 mm, a wall thickness of at least 3.5 mm, or fittings. You can also use a rectangular profile, the main thing is that its cross-sectional area does not exceed 150 mm2.
Three strips of metal 120 cm long, 4 cm wide and at least 4 mm thick.
A stainless steel metal strip 40*4 mm, having a length from the location of the system to the porch of the house.
Bolt M8 or M10.
Copper wire, for example, PV-3, with a thickness of at least 6 mm2 (depending on the cross-section adopted for the phase conductor).

Important! Do not skimp on the thickness of the grounding conductors, because... the durability and reliability of your grounding will depend on this! Having prepared everything you need, you can proceed to making grounding in a private house.

Having prepared everything you need, you can proceed to making grounding in a private house.

How to connect the phase and neutral wires

Re-grounding resistance at the input to the electrical installation of a country house

What should be the resistance of the grounding device when re-grounding? The power network of a country house refers to electrical installations with voltages up to 1 kV (1000 Volts) with a solidly grounded neutral (TN system). The maximum permissible resistance to current flow DOES NOT DEPEND on the number of phases or the allocated power. The grounding resistance depends on the LINE VOLTAGE OF THE SUPPLY LINE. The standard line voltage for residential supply lines is 380 volts. Line voltage is the voltage between phase wires - its value is 380V. Phase voltage is the voltage between the phase and neutral wires - its value is 220V.

The resistance of the grounding device, not connected to the neutral wire of the electrical network, for single-phase or three-phase input should not exceed 30 Ohms.

Acceptance test standards. The highest permissible values of resistance of grounding devices of the PUE.

Installation of a panel with automatic machines

So, let's look at several options.

First option. It is necessary to make a device in a house where all three phases are connected. Most of these are houses with elevators. Professional electricians recommend using all three phases for different apartments. Therefore, the input machine will be three-phase. As a rule, introductory machines are usually installed in the panel at the top left. From it the wires will already be distributed to apartment automatic machines. In the case when three apartments are connected to the switchboard, it is best to power each apartment with its own phase: this way there will be no risk of overloading any of the shoulders. Next, you need to find out what kind of electrical connection is in each of the apartments.
The second option is division by premises. In older homes, wiring was usually divided into two parts: lighting and outlets. Consequently, only two machines were used for each apartment.

In modern houses, they try to install a two-phase machine or at least a separate single-phase one for “power equipment”. The equipment, in turn, can be divided into the following categories:

washing machines;
dishwashers;
electric stoves;
other powerful household appliances.

Wiring

A little about mechanics

Common mistakes when performing installation work

Experts note that the following mistakes are most often made during self-installation:

An attempt to protect the electrodes from corrosion by painting. This method is unacceptable, because prevents flow into the ground.
Connection of steel metal connection with pins with bolts. Corrosion quickly breaks contact between elements.
Excessive distance of the circuit from the house, which significantly increases the resistance of the system.
Using too thin a profile for the electrodes. After a short period of time, corrosion causes a sharp increase in the resistance of the metal.
Contact of copper and aluminum conductors. In this case, the connection deteriorates due to contact corrosion.

If design flaws are discovered, they should be corrected immediately. Excessive increase in electrical resistance or disruption of circuit integrity disrupts the operation of grounding. The circuit will not be able to guarantee safety.

A grounding loop is necessary for a private home. This design will ensure electrical safety for residents and eliminate tragic accidents. However, it should be remembered that the effectiveness of grounding depends on the correctness of calculations, choice of circuit and installation. If you doubt your own abilities, then it is better to use a ready-made kit.

Hot work

The first rule is not to panic and take your time.
The second rule is to use a special indicator screwdriver.

Let's look at everything in detail. If it is not possible to turn off the access panel, then from the “affected” machine, then you need to perform the following steps:

Remove the power, that is, unhook the input wire from it.
Wear sunglasses to protect your eyes from sparks and electrical protective rubber gloves.
Arm yourself with an indicator screwdriver and a regular screwdriver with an insulating handle.
On short-sleeved clothing, wear something with long sleeves over it.
Now, carefully, without touching any metal objects in the shield, since in the event of an accident the phase may “sit” on them, unscrew the input contact screw with one hand, and with the other hand remove and bend the wire so that it does not touch any metal surface.

It is prohibited to take this wire by its exposed part!

Sparking during such a shutdown is normal. The wire just needs to be pulled away from the contact confidently and quickly to a distance that cannot be penetrated by a spark.

Let's analyze the situation with diagrams

From the point of view of the flow of electric current, there is no difference between grounding and grounding. The neutral wire in any case has electrical contact with physical ground.

Accordingly, when a phase is shorted to the housing, the same short circuit will occur and the circuit breaker will turn off. Of course, (subject to proper connection: the socket must have a third ground contact, just like an electrical appliance. For this reason, electricians, violating the requirements of the Electrical Installation Rules, often separate the ground bus from the zero contact of the input panel.

Let's imagine a situation where the neutral wire is broken for some reason:

loss of contact due to corrosion (in old high-rise buildings this is a working situation);
mechanical rupture of the cable due to repair work with violations of technology (unfortunately, also not uncommon);
unauthorized intervention by a home-grown “electrician”;
accident at the substation (only the zero bus may be disconnected).

In the diagram it looks like this:

When organizing protective grounding, the electrical circuit between the physical “ground” and the grounding contact of the electrical appliance is broken. The installation becomes defenseless. In addition, a free phase without a load can create a potential equal to the input voltage at the nearest substation. Typically this is 600 volts. You can imagine the damage that will be caused to the electrical equipment that is turned on at this moment. In this case, there is no current leakage to the physical ground, and the circuit breaker will not trip.

Imagine that at this moment you simultaneously touch a phase (a breakdown on the body of an electrical installation) and a metal object that has a physical connection with the ground (a water tap or a heating radiator). You can get electrocuted at 600 volts.

Now let's see what the difference is between grounding and neutralizing (in our diagram). If the zero bus breaks, the power to all electrical installations in this circuit will simply disappear. There will be no electric shock under any circumstances: the electrical circuit between the physical ground and the grounding contact of electrical appliances is not broken. We have already preserved our health. Now let's see what happens to electrical installations. The maximum damage is a burnt-out incandescent lamp closest to the input panel. Moreover, trouble will only occur if the voltage on the phase wire increases. The current strength will increase (according to Ohm's law), the circuit breaker will work, and perhaps other electrical appliances will not be affected.

It is for this reason that the PUE strictly prescribes: protective grounding and grounding of electrical installations must be organized independently of each other, using different lines.

For reference: Wire color coding is usually used:

The phase is brown or white.
The working zero is blue.
Protective grounding is a yellow-green shell.

If you have a modern home, then grounding and grounding are carried out in accordance with the Electrical Installation Rules. This can be easily checked by looking at the input cable in the panel. In addition, you can check the correct connection yourself.

Why do you need a partner?

As you know, when working with electricity you need to take as many safety precautions as possible. Another practical advice from experts is to repair electrical wires with a partner.

Residual current device

To increase safety during operation of electric devices also use the so-called residual current device, abbreviated as RCD. Together with the RCD they provide a 100% guarantee of protecting people from electric shock.

Let's look at the principle of operation of an RCD, for which we will imagine it as a water supply system. Water flows through pipes, just as current flows through wires. And if suddenly a hole appears in the pipe, the water begins to leave, and its amount at the exit of the section will be less than at the entrance. The RCD controls such a leak, but not of water, but of electricity.

If the device body is energized, but there is no leakage, the RCD does not respond. But as soon as a person touches the body, a path for current leakage appears, a “hole” - the RCD opens the circuit in a fraction of a second.