RCD purpose: wiring diagram in a household electrical network, installation

Why do you need

Installation of such devices is necessary according to several reasons. Mainly, it was designed for protection. From what? Firstly, the RCD protects people from electric shock, especially in cases where there are malfunctions in the electrical installation. Secondly, the device trips and turns off the current due to accidental or erroneous contact with the current-carrying parts of the electrical installation, in case when leakage occurs. And, thirdly, ignition of the electrical wiring is prevented in the event of a short circuit. As can be seen from the above, this machine actually performs the most important function.

RCD

Today you can find differential automata, the peculiarity of which is to combine a circuit breaker and an RCD. Their advantage is that they take up less space in the shield. In all cases, when connecting, all contact connections should be brought to it not from below, but only from above. One of the reasons is a more aesthetic appearance. But there is a much more significant reason. The fact is that the RCD is able to reduce the efficiency of the work of all household items. Moreover, during repair work, the electrician will not get confused, and he will not have to study complex, intricate circuits. So, now it's time to consider connectivity options.

How to independently connect the RCD?

The lethal current for humans is 0.1A. The last step is to check the RCD itself, which is carried out by pressing the test button.
A breakdown of this device occurs when the value of a single-phase electric current of operating parameters is exceeded. They will have the same rated operating voltage - V or V.
In home wiring, it is practiced to use a device with a mA cutoff current. It will provide protection against voltage overloads and short circuits, while the RCD will monitor the absence of current leakage, thus obtaining a combined protection.
This can protect against electric shock and save health or life. Decide on the diagram whether you will have a residual current device on a separate line or after the meter.
Unforgivable Movie Mistakes You Probably Never Noticed There are probably very few people who don't like watching movies. The lethal current for humans is 0.1A.It is advisable to carry out a check using the button at least once a month. The video shows how this is done in practice.

What is a security connection device

The disadvantage of the scheme is the difficulty in finding the damage site. Residual current device from the inside The principle of operation of the RCD is that if there is a current leakage in the wiring, its value along the conductors of the phase and zero will be different.

The second value will be the differential current, upon reaching which, the protection will operate. A negative point in the functionality of this device is the reaction directly to the manifestation of leakage current, regardless of the source of occurrence. This will also lead to malfunctions. So that high currents at the time of the accident do not have a negative impact on the residual current device, it must be connected to the circuit together with the machine. How to look younger: the best haircuts for those over 30, 40, 50, 60 Girls in their 20s don't worry about the shape and length of their hair.

Such a scheme is not dangerous, but the RCD will not function with it, since its principle of operation will be violated. After the counter, connect the RCD. A grounding bar must be installed.
Three-phase RCD working principle. How a three-phase RCD works

RCD connection diagram

The principle of installation of an RCD in a two-wire electrical network

In the premises of the old layout, two-wire wiring (phase / zero) is used. There is no ground conductor in this circuit. The absence of a ground conductor cannot affect the effective operation of the RCD. A two-pole RCD installed indoors with this type of wiring will work correctly.

The difference between the installation of an RCD with and without grounding is only in the principle of disconnecting the device.In a grounded circuit, the device will operate at the moment a leakage current appears in the network, and in a circuit without grounding, at the moment a person touches the device case, which is under the influence of a current leakage.

An example of installing an RCD in an apartment with a single-phase two-wire electrical network (diagram):

Option for an apartment with two-wire wiring

The specified scheme is also suitable for one group of consumers. For example, for kitchen electrical equipment and lighting. In this case, an RCD is installed after the introductory circuit breaker, which protects the circuit section and electrical appliances located after it.

For a two-wire electrical network of a multi-room apartment, it is preferable to install an introductory RCD after the introductory circuit breaker, and from the introductory RCD, branch the wiring to all necessary consumer groups, taking into account their power and installation location. At the same time, an RCD is installed for each consumer group with a lower differential current setting than that of the input RCD. Each group RCD is equipped with a circuit breaker without fail, this is necessary to protect against short circuit current and overload of the electrical network and the RCD itself.

An example of an electrical wiring diagram for a multi-room dwelling, which is protected by residual current devices, is shown in the figure:

Multi-room option

Another advantage of installing an introductory RCD is its fire-fighting purpose. Such a device controls the presence of the maximum possible leakage current in all sections of the electrical circuit.

The cost of installing such a multi-level protection system is higher than that of a system with a single RCD.The undoubted advantage of a multi-level system is the autonomy of each protected section of the circuit.

For an objective understanding of the process of correctly connecting an RCD in a two-wire electrical circuit, a video is shown.

Video: RCD installation diagram

RCD connection diagram in a three-wire (three-phase) electrical circuit

This scheme is the most common. It uses a four-pole RCD, and the principle itself is preserved, as in a two-phase circuit using a two-pole RCD.

Incoming four wires, three of which are phase (A, B, C) and zero (neutral) are connected to the input terminals of the RCD, according to the terminal marking applied to the device (L1, L2, L3, N).

Wiring diagram

The location of the neutral terminal may differ on RCDs from different manufacturers.

It is important to observe the correct connection at the input and output of the device, the correct operation of the RCD depends on this. Otherwise, the order of connecting the phases does not affect the operation of the RCD.

Connection in a three-phase network

For an objective understanding of the RCD connection diagram in a three-phase circuit, a diagram is given - an example.

Multi-level protection

It can be seen from the diagram that the branched electrical circuit after the introductory four-pole RCD is made like a two-wire RCD connection circuit. As in the previous example, each section of the circuit is protected by an RCD. against leakage currents, and by an automatic switch from short-circuit currents and from overload in the network. In this case, single-pole circuit breakers are used. Only the phase wire is connected through them.The neutral wire goes to the RCD terminal, bypassing the circuit breaker. It is not necessary to connect neutral conductors to a common node after exits from the RCD, this will lead to false alarms of the devices.

The input RCD in this case has a working current rating of 32 A, and the RCD in some sections has ratings of 10 - 12 A and differential current settings of 10 - 30 mA.

How to find the culprit if knocked out?

RCD operation is not uncommon in modern apartments. But many residents simply do not know what to do if it worked? Most simply turn the device back on. However, this approach is unacceptable if the cause of the operation is not found. And finding the cause is not so difficult even for an amateur. There would be an electric meter in the apartment, and preferably not too old.

The step by step guide for this is:

1. First you need to remove all the plugs from the sockets.
2. Then you have to turn on the RCD to find the "culprit" of the operation. If it didn’t turn on, then the RCD or wiring is to blame for the operation of the device.
3. Next, you will have to cut down the access or main apartment machine. If this cannot be done, the reason for the operation of the RCD is its electromechanics. You will have to send the device in for repair. You should not try to fix anything yourself, since such a correction is the work of qualified specialists. And after repair, the RCD must be verified.
4. If the main machine (or access machine) nevertheless turned on, but when the voltage was applied, the RCD knocked out again on empty wiring, there may be several reasons:

• internal unbalance of the differential transformer in the protective device;
• sticking of the "test" button;
• wiring fault.

1. If, when turned on under voltage (despite the meter), the “ground” indicator flashes even for a second, then there is a leak in the wiring. It is necessary to take measurements, and for this it is imperative to call specialists (from a private company, if the RCD was installed independently, or municipal electricians, if the device was connected in the order of wiring reconstruction). Professionals with the help of modern devices find a leak in a quarter of an hour.
2. Before calling specialists, it is worth looking at the sockets (you will have to open them for this), because, for example, insect excrement gives such a good leakage from the phase to the ground.
3. If the wiring does not raise suspicions, and the RCD still knocks out “on empty”, then the malfunction lies inside the device.
4. When the RCD is triggered by a consumer connection, but there are no signs of a short circuit, everything that can be turned on must be turned on, according to the indexing. And, looking at the counter, turn on the RCD again. Here, in addition to the "land", the "reverse" or in another way "return" may also be displayed. And this indicates a large circuit reactivity, inductance or capacitance.
5. The defective consumer is searched in reverse order. By the way, he himself may not reach the tripping of the RCD, so you should turn on everything, and then turn off the suspicious ones in turn and try to turn them on. Turned on? This is the "reverse" consumer. It urgently needs to be taken in for repair.
6. In apartments with TN-C-S wiring, a situation is possible when it is not possible to determine the source of the RCD trip. Then the most likely cause is bad ground. The existing grounding still retains its protective properties, but it no longer removes the higher components of the interference spectrum.In this case, the conductors begin to work like an antenna, and housing becomes almost an analogue of apartments with TN-C wiring and a common RCD. You should contact the operator with the requirement to bring the ground loop to the norm - he is obliged to do this.

RCD Installation Instructions

First you need to choose a place to mount the device. 2 options are used: a shield or a cabinet. The first resembles a metal box without a lid, fixed at a height convenient for maintenance.

The cabinet is equipped with a door that can be locked. Some types of cabinets have openings so that you can remove them. meter readings, without opening the door specially, and turn off the devices.

Protective devices fix on mounting DIN railsplaced horizontally. The modular design of automata, difavtomatov and RCD allows you to place several pieces on one rail

The neutral wire is always connected to the left terminals at the input and output, and the phase wire is connected to the right terminals. One of the options:

• input terminal N (upper left) - from the input machine;
• output N (lower left) - to a separate zero bus;
• input terminal L (upper right) - from the input machine;
• exit L (lower right) - to group machines.

By the time the protective device is installed, circuit breakers may already be installed on the switchboard. To arrange the arrangement of devices and wires, you may have to rearrange the devices in a certain order.

We present an example of installing an introductory RCD in an electrical cabinet, where there is already a meter, an introductory machine and several circuit breakers for individual circuits - lighting, socket, etc.

Never connect an RCD at the input - it always follows the general input circuit breaker. If a counter is used, then the residual current device moves to the third position from the input.

Description of the connection process:

• we install the device on a DIN rail to the right of the machine - just attach it and press with a little effort until it clicks;
• we stretch the cut and stripped wires from the machine and the zero bus, insert them into the upper terminals according to the diagram, tighten the fixing screws;
• in the same way, insert the wires into the lower terminals and tighten the screws;
• we test - first we turn on the general machine, then the RCD, press the "Test" button; when pressed, the device should turn off.

To make sure the connection is correct, leakage current is sometimes staged. They take two working wires - "phase" and "ground", at the same time they bring the electric lamps to the base. There is a leak, and the device should work immediately.

How to choose and not make a mistake

Before connecting a four-pole RCD in a house, it is necessary to take into account the grounding system of the mains through which electricity is supplied to it. A leakage current will be simulated, the device should react and turn off. It is often confused with a protective neutral conductor, which is designed to connect a ground wire.
When a current leakage occurs along any of the wires, an imbalance occurs, and, as a result, the core of the transformer is magnetized. Know the regulatory documents and the selection methodology It is clear that the average layman is most likely not familiar with these things, so he will invite the master.
The current that feeds electrical appliances flows through one of the core windings in one direction.
There are RCDs in which the allowable leakage current can be adjusted. The grounding component is designed to drain currents resulting from a short circuit, is not interconnected with the main phases and is connected to the protective neutral conductor.
This element is equipped with perforated holes, which are designed to connect with the rear latches of the machine.
Most accidents are due to incompetence. Connect the machine and after applying voltage, using the previously described methods, check the correct functioning of the system.
How to choose The first parameter by which the RCD is selected is the type of wiring in the room where the device will be installed.
Switchboard - layout for 3-phase input

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Installation of a differential machine in a network with one and three phases

Before proceeding with the installation of equipment, you need to find the "Test" button on its body and hold it down. This allows you to create an artificial current leakage, to which the device reacts by switching off. This feature checks the functionality of the protective device. If during the test the network was not disconnected, then the installation of this device should be abandoned.

Connection rules

With a standard single-phase electrical network (at a voltage of 220 V), a device with two poles is installed. Installation of a differential machine in a single-phase network requires the correct connection of the neutral conductors: from the load, zero is connected from the bottom of the case, respectively, from the top from the power supply.

Video - Connecting a differential machine to a network with one phase

The installation of a difavtomat with four poles is necessary if there is a three-phase electrical network, where the voltage will be 380 V. Otherwise, the connection method has no fundamental differences. The difference is that the three-phase apparatus has an impressive size, which means it requires more space. This is due to the need to install an auxiliary differential protection unit.

There are certain types of protective devices marked 230/400 V. Their peculiarity is that they are intended for networks with both one and three phases.

Connection diagrams

According to the rules, when drawing up an automation connection diagram, it should be borne in mind that the difavtomat must be connected to the neutral and phase wires only on the branch for which it is intended.

Wiring diagram of a differential machineWiring diagram of a differential machine

Introductory machine

The difavtomat with such a connection must be fixed at the input of the wiring. The connection scheme received a characteristic name because it involves the protection of different groups of consumers and branches.

When choosing a device for this scheme, all line criteria must be taken into account, especially the degree of power consumption. This method of connecting the protection device has many advantages:

• saving money on the purchase of equipment, because only one RCD is installed on the whole electrical network;
• no need to purchase an overall shield (the device has a minimum size).

Connection of an introductory machine for several energy consumers

However, such an electrical circuit has some disadvantages:

• in the presence of interruptions in the operation of the protection system, the power supply to the apartment or private house is turned off, and not to individual lines;
• again, in the event of malfunctions, a lot of time and effort will have to be spent in order to find an inoperative branch. In addition, you will have to look for the cause of the failure.

Instructions and wiring diagrams for RCDs

In every house, in every city apartment, there is just a huge amount of household appliances and appliances, working at the expense electricity. For the normal operation of this equipment, it is necessary to install a special device in the room, the so-called RCD. Otherwise, all equipment will be at immediate risk. In the event that until that time it was not possible to collide with this device, then this article will tell you what an RCD is and how to connect it by all rules. But initially it will be necessary to figure out what exactly this device is needed for.

The figure shows RCD connection options

Connection rules

Realize installation of a control device of this type necessary for a number of reasons. First of all, the RCD was designed specifically to protect a person from electric shock. This is especially true when there are real problems in the system. Then it is necessary in order to prevent current leakage. And in the end, the device is designed specifically to prevent fire and ignition of electrical wiring in the event of a short circuit. So, there are at least three reasons why it is impossible to do without this device.

In order to connect a protection device, you must follow a number of specific rules:

• RCD must be connected after the input device.
• In accordance with the norms, “0” and the phase of that electrical circuit, which especially needs additional protection, must pass through it.
• Special technical elements for the installation of RCDs should be used.

Attention! Some are interested: is it possible to connect an RCD without grounding? Experts say that yes, this option is possible. The only thing to remember is the need to create and assemble a circuit according to a certain scheme, which differs significantly from the usual

The only thing to remember is the need to create and assemble a circuit according to a certain scheme, which is significantly different from the usual ones.

How to connect correctly?

To connect a security device in a private house or city apartment, it is necessary to take into account the method and type of connection:

how to connect an RCD and machines - according to the rules, you should not connect an RCD in front of the machine, because the device will not be able to function normally in normal mode. Power to the device should be supplied from above;

RCD connection in the shield in the photo

how to connect an RCD in a shield - in this case, the RCD will protect the entire apartment as a whole. This method is the easiest to connect an RCD;
how to connect RCD without grounding - when connecting RCD without grounding, you must use the diagram below;

RCD connection without grounding in the picture

how to connect an RCD to a two-wire network - is one of the most common methods for connecting a protection device to an electrical network;
RCD connection in a three-phase network with grounding - in this particular case, there is often no neutral. Only phase electrical cables are used (without the use of winding). There will be an empty zero terminal;
connecting an RCD to an electrical wiring circuit - a protective device is an important element of any electrical wiring system. This will avoid force majeure in the apartment and private house;

In the photo, the connection of the RCD to the wiring circuit

connection of a four-pole RCD - this option is currently the most common. Fundamentally, this option is no different from connecting to a single-phase network. In fact, the number of poles and trunk connections is changing;
RCD for two phases of connection 10 mA - this option involves the operation of a protective device when an electrical leakage of five to ten mA occurs;
connection of an RCD and an automatic circuit 380 V circuit - experts recommend connecting a four-pole type RCD to a circuit with such an indicator.

It should be understood that it is necessary to connect the device only when the shield is turned off. In case of real need, you should purchase one powerful device and install it on the entire apartment building. But it should be understood that this option involves the use of a device with a high level of voltage. To avoid errors and possible problems, you need to attach all the elements in series.

To avoid real problems when connecting, it is necessary to follow a certain schematic arrangement.To do this, use the following embedding schemes for RCDs and abb automata:

Why is RCD needed?

To understand the principle operation of the RCD and its features installation should consider a number of key points.

First of all, you need to understand that the use of a large number of electrical appliances in everyday life increases the risk of a person falling under the influence of electricity. Therefore, the formation of protective nodes that protect against this dangerous factor is a necessity in modern residential premises. The Residual Current Device itself is an element of the protection system, and functionally has several purposes:

• In the event of a short circuit in the wiring, the RCD protects the room from fire.
• At the moment the human body gets under the influence of electric current, the RCD turns off the power to the entire network or a specific electrical appliance to perform protection (local or general shutdown depends on the position of the RCD in the power system).
• And also the RCD turns off the supply circuit when the current in this circuit rises by a certain amount, which is also a protection function.

Structurally, an RCD is a device that has a protective shutdown function, outwardly similar to a circuit breaker, but has a different purpose and test switching function. The RCD is mounted using a standard din-rail connector.

The design of the RCD is two-pole - a standard two-phase electrical network of alternating current 220V.

Such a device is suitable for installation in standard buildings (with electrical wiring made with a two-wire wire).If an apartment or house is equipped with three-phase wiring (modern new buildings, industrial and semi-industrial premises), then in this case an RCD with four poles is used.

Two-pole and four-pole version

The device itself has a diagram of its connection and the basic characteristics of the device.

• Serial serial number of the device, manufacturer.
• The maximum value of the current at which the RCD operates for a long time and performs its functions. This value is called the rated current of the device, it is measured in amperes. It usually corresponds to the standardized current values ​​of electrical appliances. Designated on the instrument panel as In. This value is set by taking into account the cross section of the wire and the design of the RCD contact terminals.
• RCD cutoff current. The correct name is rated residual current. It is measured in milliamps. On the body of the device is marked - I∆n. The specified value of the leakage current indicator causes the protective mechanism of the RCD to operate. Operation occurs if all other parameters do not reach emergency values ​​and the installation is performed correctly. The leakage current parameter is determined by standard values.
• The value of the rated differential current that does not lead to an emergency shutdown of the RCD operating under normal conditions. Correctly called the rated non-switching differential current. Marked on the case - In0 and corresponds to half the value of the RCD cutoff current. This indicator covers the range of leakage current values, during the appearance of which an emergency operation of the device occurs.For example, for an RCD with a cutoff current of 30 mA, the value of the non-tripping differential current will be 15 mA, and the emergency shutdown of the RCD will occur during the formation of a leakage current in the network with a value corresponding to the range from 15 to 30 mA.
• The voltage value of the operating RCD is 220 or 380 V.
• The case also indicates the highest value of the short-circuit current, at the time of the formation of which the RCD will continue to operate in good condition. This parameter is called the rated conditional short-circuit current, denoted as Inc. This current value has standardized values.
• The indicator of the nominal trip time of the device. This indicator is referred to as Tn. The time it describes is the interval from the moment the differential breaking current is formed in the circuit to the time at which the electric arc was completely extinguished at the power contacts of the RCD.

Example notation:

Designation example main characteristics of the device