What is the difference between a difavtomat and an ouzo? What is the difference between an RCD and a differential circuit breaker and which is better to use? What is the difference between a differential circuit breaker and an RCD?

19.10.2023

VD 63 1dif or RCD how to distinguish by external signs and by inspection. Choose a reliable device for protection against leakage currents in your home and apartment. What is the difference between an RCD and a differential automatic device, which one to choose, why do you need an RCD or a differential automatic device, and much more, read the article.

The main difference between the two devices is their functionality. A residual current device is an electrical device designed to protect a person from electric shock caused by leaks in the network. In addition, it monitors the parameters of household electrical networks. RCD does not open the electrical circuit in the event of overloads and short circuits.

Differential automatic– a switching device that combines the functions RCD and circuit breaker, i.e. supplemented with short circuit protection function.

Rice. 1. Main visual difference between circuit breakers

Differences between a circuit breaker and a differential switch. machine gun

Externally, the devices are almost identical. Distinguishing them can be difficult even for novice electricians. The wrong choice of device can lead not only to incorrect operation of electrical appliances, but also to emergency situations. There are several points to look for difference between RCD and RCBO.

Functionality. RCD triggers if a leakage current appears in the circuit, i.e. shutdown occurs only after a person touches the damaged equipment. The setting switches off the faulty distribution network before the electric current hits the body.
Differential switch - in addition to all the listed functions, it turns off lines during overloads and short circuits.
A residual current device is a network fault indicator that detects a leak.
Visual differences. Leading electrical manufacturers usually indicate the type of electrical appliance on the side or front of the product (VD or RCD).
Marking. If in the designation of the device there is a Latin letter B, C, D (type of release characteristic) before the rated current value, this means that this is a difautomatic device. IN RCD indicate only the rated current.

Important: technically, it is not possible to manufacture difavtomats with a nominal value higher than 63 A. If a current of 80 A or 100 A is written on the device, then this is definitely an RCD.
The electrical circuits shown on the case and passport indicate the principle of operation of the protection. The outlines of a differential transformer (an oval rectangle), a thermal and electromagnetic release indicate that the buyer is facing difavtomat.
Geometric dimensions. Both types of electrical devices are modular, i.e. sizes are unified. You should not trust the opinion that the difavtomat has a large width. Modern releases have minimal dimensions, due to which they easily fit into standard boxes (2 modules for 220V networks, 4 modules for 380V networks).

The video describes in detail which electrical device to choose to protect your home from leakage currents, and describes in detail the connection diagrams and stages of installation on an electrical panel.

RCD or difavtomat? Which is better to choose?

Nuances of operation

The pricing policy for both types of devices is ambiguous. Price RCD higher than a similar differential machine from the same manufacturer. This is due to ensuring the reliability and maintainability of the devices. If the circuit breaker and RCD, As a rule, one product must be replaced. In the case of a differential switch, otherwise: a failed electrical protection cannot be repaired - a complete replacement of the unit is required. The practice of electricians shows that they break down more often difavtomats due to low-quality electrical energy, lack of reconstruction of electrical distribution networks and electrical equipment at substations.

If the residual current device fails, it is possible to temporarily restore the power supply to the facility (apartment, while ensuring that the damaged section of the line is de-energized) by turning on the circuit breaker, which is located in the electrical circuit in front of it. In case of installation difavtomat, installation of a working electrical product will be required.

Differential switches It is preferable to install in houses and apartments where power outages rarely occur. A residual current device paired with circuit breakers provides reliable protection with minimal financial investment.

What is the difference between an RCD and a machine in electrical engineering?

Domestic manufacturers produce products with sufficient characteristics. But they are inferior to foreign ones in response time, reliability of individual elements and quality of materials used. For an economically feasible power supply to a home with multi-level protection, you can combine electrical protection devices from different manufacturers. Introductory RCD for 300 and 100 mA of domestic production, and the load wiring is carried out through devices from ABB, Siemens, Schneider-Electric and similar with leakage currents of 10 and 30 mA.

Important: when the automatic circuit breaker is triggered, it is more difficult to determine the reason for the shutdown. Whether it is an overload or a leakage current, to find a fault it is necessary to completely remove the load and turn on the electrical appliances one by one. Some manufacturers equip devices with diffraction indicators, which makes it easier to find a breakdown.

For each power supply facility, a set of electrical protections is selected individually based on the condition of the wiring, type of network reconstruction, load and type of consumers (electrical appliances), and financial capabilities.

Rice. 2. Difference in the scheme indicated on the body

What is the difference between ABB FH202 and F202 RCDs

Residual current devices are two-pole, designed for use in 230 V networks. The rated leakage currents are the same - from 16 to 300 mA. The difference is the breaking capacity of the samples.

The FH202 (home) series is designed for installation in apartments and private houses, has a more simplified design and a breaking capacity of 6000 A.

Rice. 3. Front panel FH202

Electrical devices of the F202 series are advanced models, with a breaking capacity of 10000A, and are structurally more reliable. Made with an additional clamp for fastening the busbar, which allows you to easily connect several outgoing lines to one pole.

Rice. 4. General view of F202

For wet rooms (bathrooms, bathrooms, baths, etc.) and children's rooms it is necessary to use RCD F202 at 10mA, because Only this line will provide the necessary speed of protection when leakage currents occur.

Technical differences between electronic and electromechanical RCDs

According to the operating principle RCD are divided into two types: electromechanical and electronic. The effectiveness of the protection and performance characteristics do not depend on the type.

Electronic devices perform their function when there is voltage in the network, i.e. For the protection to operate, the faulty electrical appliance must be included in the electronic circuit. The main element of the work is an electronic board with an amplifier, the operation of which requires voltage from an external network of 220 V. I.e. The device does not detect faults when electrical appliances are turned off.

Electromechanical products are capable of detecting leakage current, regardless of the presence of voltage in the electrical network. The “heart” of the device is a differential transformer. When a leakage current flows, voltage is induced in the secondary winding, and the polarized relay activates the protection mechanism.

How to avoid buying the “wrong” RCD?

In order to know how to distinguish VD1 63 differential or RCD visually, you need to pay attention to the diagram shown on the case. On electromechanical samples, the secondary winding of the differential relay is directly connected to the relay. There is no jumper to power the element from an external network.

Electronic RCD equipped with a circuit with an electronic amplifier board (in the form of a triangle).

To accurately check devices at home, you need a 1.5..9V battery (or battery), known to be charged. RCD must be set to the “on” position. Connect two wires to the electrical device terminals, then to the battery poles. If there is no change, the polarity should be changed.

If the protective device is electromechanical, then when an electric current flows in the secondary circuit, a jump is detected, which triggers the relay and turns off the device. The lack of response to connecting the battery indicates that RCD electronic and does not work without external voltage.

An equally effective method is using a permanent magnet. If you hold the element near the front of the case, the switched on device will work if it is electromagnetic.

It is important for the consumer to decide what type of device is needed. Lack of load in the network can be for several reasons: failure of the external power supply network, repair work on the line. The cause may also be burnout of the neutral wire in the shield. In this case, the electronic type protective device does not respond to a malfunction: electrical appliances do not work, but the power to the phase wire does not disappear. It is in this case that the likelihood of emergency situations arises: if the insulation breaks down, for example, on a boiler, the phase gets into the housing. And when a person accidentally touches it, a leakage current begins to flow. In this case RCD will not work due to the lack of normal power supply.

If you observe frequent power surges in the network, differential The transformer is subject to rapid wear and failure. A burnt-out board with an amplifier is the cause of electric shock with all the ensuing tragic consequences. At the time of buying RCD electronic type, the sample should be tested regularly. Weekly checks will help maintain the protective functions of the network.

Difference between RCD type A and AC

By gender differential Leakage current protection devices are divided into two types. In household AC networks with a voltage of 230 V, alternating current does not always occur. It can be constant or pulsating depending on the nature of the damage to the lines.

Electrical devices of the AC type react to alternating current loads that arise in the primary circuits of electrical appliances: washing machines, water heating tanks, etc. or in case of phase breakdown on the housing.

The type A residual current device responds to direct and alternating pulsating current. This gives higher sensitivity to changes in the operating parameters of the device.

Constant pulsating leakage current occurs in electrical appliances where electrical circuits contain secondary circuits (microwave ovens, LED lamps, and other electrical equipment with switching power supplies and electronic control elements). If the secondary switching is damaged, a pulsed direct current leak occurs.

RCD type A are at least 2 times more expensive than analogues. Therefore, the feasibility of purchasing them must be justified.

Important: according to the current PUE (clause 7.1.78 7th edition), the installation of protective devices marked A is recommended for household consumers.

Depending on the nature of the action, the devices are marked accordingly on the case: an alphabetic abbreviation and an emblem in the form of a sine wave.

Home electrical is a rather complex and varied topic, and it is advisable for every homeowner to know the basic details, since not only financial costs, but also the safety of your home depend on it. In this article we will try to find out which is better - a difavtomat or an RCD.

Introduction to the topic, or what is a difavtomat?

To understand this issue, let’s first try to define the basic concepts. So, difavtomat.

A device called a differential circuit breaker successfully combines the functions of both an RCD and a conventional circuit breaker. This machine protects a person in the event of touching exposed areas of a conductive part of a wire or those parts of electrical networks that are energized due to damage to the wiring or other similar factors. Today there are a huge number of such devices, which are designed for both different operating currents and different leakage currents.

Its main distinguishing feature is that it consists of two well-separated functional parts: a circuit breaker (two or four poles), as well as an electric shock protection module. The difavtomat should be installed exclusively on a mounting DIN rail, and this design takes up much less space than a combination of an RCD and a circuit breaker.

Considering the response time, which is only 0.04 seconds, differential circuit breakers provide the most adequate protection against electric shock to a person in almost any operating conditions. It is also important that the differential machine qualitatively protects devices in the network from overloads that inevitably arise during various types of emergencies. And further. Its design ensures the fastest power outage in conditions where voltage surges in excess of 250 V are observed in any part of the network.

Considering the unenviable characteristics of domestic electrical networks, as well as the degree of their deterioration, the last characteristic is especially important.

The main advantages of the automatic machine

Very high response speed.
. Protection of equipment from power surges and operational overloads.
. Possibility of operation in conditions from -25 to +50 degrees Celsius.
. Huge wear resistance threshold.

What is an RCD?

We cannot ignore the second “opponent” in the debate on the topic “difavtomat or RCD”. What is an RCD?

This abbreviation stands for “residual current devices”. Triggering occurs when the presence of leakage currents is detected. Simply put, how much current came to the device through one wire, the same amount should go through another section of the wiring. If the current begins to flow to the ground or through the grounding wire, the protection is instantly activated, immediately disconnecting the network from the power source.

Such a system must (!) be installed on socket groups, as well as on boilers, washing machines and electric cookers. These types of devices do not protect (!) your equipment and wiring from system overloads or short circuits.

The last circumstance is very often not taken into account by would-be electricians, who, in order to reduce the cost of the circuit, often use only an RCD. In addition, there is also selfish interest when it is passed off as a differential machine, the cost of which is higher.

Basic information about the RCD device

What is the operating principle of an RCD? Its work is based on the response to changes in the differential current in conductors.

What is a current sensor? This is the most common transformer, but made as a toroidal core. The response threshold is set using a magnetoelectric relay, which has extremely high sensitivity.

It is important to note that all RCDs made according to this classical scheme are extremely reliable and simple devices with very high reliability and reliability.

It is necessary to warn that today there are also electronic RCDs, which are based on a special electronic circuit. A relay or circuit acts on a mechanism that opens the electrical circuit if necessary. This is what the RCD device includes.

What parts does it consist of?

From the contact group itself, set to the maximum current value.
A spring that directly opens the circuit if any problems are observed in its operation.

If you want to check the device’s functionality yourself, just click on the “Test” button. In this case, current is artificially supplied to the secondary winding, and the relay is triggered (should, in any case). So, if necessary, you can easily and without any costs check the serviceability of all your equipment.

Operating principle of RCD

If we talk about the normal operating mode, then the current (I1=I2) flows in an anti-parallel direction, inducing magnetic currents in the secondary winding of the transformer (Ф1=Ф2). They have exactly the same size, due to which they mutually compensate each other. Since the current in the secondary winding in this case is virtually zero, the relay cannot operate.

RCD operation during leakage

Upon contact with conductive parts, leakage current occurs. In this case, the current I1 is not equal to I2, and therefore a current appears in the secondary winding, the magnitude of which is sufficient to trigger the protective relay. It provokes a spring switch, and the RCD turns off.

Differences between the two protection systems

It should be noted that coverage of this issue is extremely important, since even some electricians are sometimes unable to distinguish these devices from each other. However, there is nothing surprising here: they are extremely similar even in photographs.

The main difference between a difavtomat and an RCD is that they are intended for slightly different purposes. We have already said this above, but we will repeat it again: RCDs cannot be used to protect equipment and wiring from overload or short circuit! Moreover, it is imperative to install the RCD in front of it, which will save the device itself from this kind of trouble. This is the difference between an RCD and a difavtomat.

Be sure to take this into account when purchasing or consulting with especially “thoughtful” electricians who will be happy to save on your own equipment.

The difavtomat is much better in this regard, because it combines both an RCD and a circuit breaker in one housing. Accordingly, this kind of device not only protects a person from electric shock, but also saves your wiring and equipment from burning out in the event of a short circuit. Thus, the RCD and the difavtomat, the difference between which we have just revealed, are somewhat diverse mechanisms.

Let us remind you once again that a differential circuit breaker can be used as a fuse in those houses where there is a constant danger of chronic overloads in the network.

This is a detailed difference between an RCD and a difavtomat. But how to make the right choice in the store? After all, we have already said that these devices are extremely similar to each other, even in photographs.

Let's buy right!

First, pay attention to the direct name of the device itself. Today, almost all manufacturers have finally met consumers halfway, deigning to indicate on the body of the device itself information about whether it is a difavtomat or an RCD in front of you. Therefore, we would not recommend buying such Chinese-made equipment. Nosy Asians either do not indicate anything at all, or they do it using only symbols that are understandable to them.

Approximately in the same category is the advice to carefully read the markings, which should always be indicated on the same body of the device or on its packaging (a less reliable option).

So, if you see on the body only the value of the rated current (16, for example), but there is no letter in front of this designation, then you are holding an RCD in your hands. Note that “16” in this case means “ampere”. If there are letters B, C or D in front of the numbers, then you have a difavtomat in your hands. The letters indicate the typical characteristics of thermal and electromagnetic releases, but at the household level it is not necessary to pay special attention to them.

In addition, it doesn’t hurt to look at the connection diagram. This method is somewhat more complicated, but it provides a 100% guarantee of differentiation. This information must also be displayed on the housing. So, if the diagram only indicates the presence of a difavtomat with the designation “Test”, then there is an RCD in front of you (do not confuse it!). Accordingly, if there is “Test” and the windings of the releases are indicated, then you are holding a differential machine in your hands.

Finally, it makes some sense to also pay attention to the overall dimensions. If we talk about old models of automatic devices, they are an order of magnitude wider than RCDs. In those days, they simply did not know how to produce sufficiently compact releases, and therefore housings with a larger internal volume were required. Attention! All modern differential automatic machines take up less space!

However, it is important to warn you that the last point is not worth paying any serious attention to, since currently there are a huge number of devices exactly the same in size.

Let's get to the main point

So, difavtomat or RCD? What conclusion can be drawn based on all of the above? What is better to choose, what is more reliable and suitable for use in domestic conditions? To answer this question, we will compare devices according to six indicators at once. After comparing all the pros and cons, we will try to come to a consensus.

Volume occupied by the device in the panel

Of course, in this aspect, any important differences can only be seen by those people who have very little space in their apartment, which does not allow them to place a normal electrical panel in the hallway. However, given the universal desire for compactness and beauty, these are the majority in our country. In addition, it is better to place everything in as small a volume as possible in advance, since later the shield will not have to be expanded if there is a need to install more powerful electrical equipment in the apartment.

So, at present, an RCD (three-phase, including) takes up much more space in the panel than a differential circuit breaker. What is this connected with? The most attentive readers themselves could already find the answer to this question in the article.

We have already talked about the need to install circuit breakers in front of the RCD, so because of this, the entire structure in the panel begins to take up more space. If you mount a differential machine there, you can save some space. For example: in the standard case, RCDs with circuit breakers occupy three modules at once, while a differential circuit breaker will occupy only two.

Thus, in this “round” the difavtomat won, allowing space to be left for the expansion of the structure.

Easy to install

As in other cases, for many electricians it is the speed and ease of installation of the entire structure that is important. If you are interested in installing an RCD, the phase is connected to the switch, and a jumper is mounted from its output to the input of the disconnect device. Zero is also connected to the input. It should be noted that there are several connection diagrams that are studied by professional electricians. As a rule, they are not needed in everyday life.

How to install a differential machine?

What about connecting the difavtomat? If we talk about a differential machine, then the phase and zero are immediately connected to the input terminals of the device, so that in the overall circuit there are much fewer jumpers and transitions. Accordingly, the internal structure of the shields is also significantly simplified.

Thus, connecting a difavtomat is much simpler and faster, so in this case too we confidently award the victory to it.

Benefits of operation

Theoretically, we can assume that one day an RCD tripped on the line of sockets in the bathroom. You can immediately assume that there is a current leak somewhere on the line. Of course, the fault detection algorithm is somewhat more complicated, but the main conclusions can be drawn immediately.

If the circuit breaker trips, then the reason here is quite obvious: overload or short circuit. You just have to find out the cause and eliminate it. Considering that the reason for turning off the machine is more or less clear, this will not be so difficult.

Now let's look at the same thing, but in relation to a differential machine. When it is turned off, the reason is not immediately clear, so you will have to check all known reasons. Accordingly, this will take much more time. This is how an RCD differs from a difavtomat in this regard.

Thus, at this stage we would give preference to an RCD.

A question of cost

Since today there are a huge number of different manufacturers on the market, let’s consider the cost of EKF products, which are quite popular among professional electricians. Thus, a standard 16 A EKF automatic circuit breaker costs about 600 rubles, an RCD for the same current strength costs the same 600 rubles, and a circuit breaker sells for about 40 rubles. By purchasing all the same things on specialized sites, you can even count on circuit breakers, which in such cases are sold almost by weight.

Before connecting the difavtomat, you should make sure that there are no frequent and sudden voltage drops. Why are we talking about this? This will become clear after considering the specifics of replacing this equipment.

Given the cost fluctuations depending on the supplier, it is difficult to talk about the advantages of one or another option.

and replacement cost

As one might assume, the characteristics of this criterion automatically follow from the previous one. Everyone knows that any electrical equipment has a certain service life, after which it becomes unsafe to operate it. Let's assume that for one reason or another the RCD or circuit breaker has failed. What to do next? Replace the failed part, after which the system will continue to operate as before.

But with the automatic rifle the situation is not so clear. Let's assume that the winding of any of the releases has failed, while the built-in RCD has shown its full functionality during testing. Alas, this does not matter, since in any case you will have to replace the entire automatic machine, the price of which makes this event extremely unprofitable. It is much easier to replace a penny machine, which most often fails.

Thus, in this round the victory is again for the RCD.

Operational reliability

There is a widespread opinion among experts that devices that combine several functions at once are less reliable compared to machines that are designed for only one thing. So RCD or difavtomat? What to choose to ensure the highest reliability?

You can argue about this for a long time, but practice has clearly shown that in reality the percentage of refusals is almost the same. It is possible that this parameter depends solely on the manufacturer. So in this case it is extremely difficult to draw a conclusion about the unambiguous advantage of this or that device.

We can only say that the RCD, the connection diagram of which we discussed above, assumes greater reliability in the conditions of domestic voltage surges. Naturally, if you do not forget to connect a circuit breaker in front of it, which we have repeatedly mentioned above.

Thus, in most cases, the RCD will still be the best choice. However, it all depends on the characteristics of your network, as well as on the size of the electrical panel.

In the process of electrical installation work, you often hear the following question: what to choose - or? So let's find out what's actually better. Differential automatic machine or RCD.

I'll tell you definitely. There is no correct answer to this question, because... the choice between an RCD and a differential circuit breaker depends on numerous factors.

But still, I will try to explain to you with examples and give you the opportunity to make your own choice.

Point 1. Free space in the shield

First of all, you need to determine the availability of free space on the DIN rail in your apartment panel.

You will ask why?

I answer, with a slight change (reconstruction) of the electrical wiring of your house, it is possible that the apartment panel will remain unchanged, and therefore your desires will not be able to come true for a simple reason - there is not enough space in the panel.

A differential circuit breaker takes up less space in the panel than a residual current device.

You all know that the RCD protects against short circuit currents and line (group) overload. Therefore, together with each RCD, it is necessary to install a circuit breaker next to it, which will take up additional space in the panel.

Point 2. Purpose

What is your goal when installing a differential circuit breaker or residual current device?

There is nothing complicated here either.

If you need protection from electric shock for a specific electrical appliance (washing machine, Jacuzzi bathtub, water heater, etc.), then you just need to install a differential circuit breaker with the technical characteristics (rated load current, leakage current) of exactly that electrical appliance that You choosed.

If you need protection against electric shock for any group (line) of sockets, then in this case it is advisable for you to use an RCD rather than a differential circuit breaker.

Why? Yes, for a very simple reason.

If the load current changes (dynamic load), and this can happen quite simply. Nowadays, electrical appliances of increasing power are increasingly used (computer power supplies, plasma TVs, refrigerators, electric kettles, Jacuzzi baths, electric boilers, etc.).

Due to an increase in load (power), the differential circuit breaker will begin to switch off due to overload and will have to be replaced with a higher rated current. In the case of an RCD, you will only have to change the circuit breaker.

Consider for yourself what is cheaper - differential circuit breaker or circuit breaker?

Point 3. Quality

At this point I can say that most combined devices, and a differential circuit breaker is such (contains the functions of a circuit breaker and an RCD) are of lower quality than special devices designed specifically for a specific purpose (RCD).

On this point, the advantage is on the side of the RCD.

Point 4. Repair and replacement

From experience in operating electrical devices, I can say with confidence that nothing lasts forever. Each device has its own service life. Therefore, in this paragraph I will touch upon the condition of repair or replacement.

And again residual current device takes advantage in front of the differential machine.

If the RCD or circuit breaker fails, either the RCD or the circuit breaker must be replaced. And if the differential machine fails, no matter for what reason, it will have to be completely replaced. From a financial perspective, these are completely different expenses.

Point 5. Power supply

Again, the advantage at this point is on the side of the RCD.

In the event of a malfunction of the RCD and its replacement, the electrical supply to your home (apartment, cottage) can be temporarily restored by installing a jumper between the circuit breaker and the load.

In a similar situation with a differential machine, temporary power can be provided if you have another differential machine or circuit breaker in reserve.

Step 6. Reason for disconnection

If for some reason your RCD has turned off, then the reason for the shutdown is obvious - a leakage current has appeared in the electrical wiring of your apartment.

If for some reason your circuit breaker protecting the RCD has switched off, then the reason for the disconnection is obvious - there is a short circuit or overload in the electrical wiring of your apartment.

If for some reason your differential machine is turned off, then the reason for the shutdown is UNKNOWN. Either leakage current or short circuit.

Conclusion

In this article I do not force anyone to use this or that device.

What is preferable: a differential circuit breaker or an RCD is decided by everyone independently, depending on the above personal observation.

When completing an electrical panel and distributing loads along the lines, few self-taught electricians, or even novice professionals, understand the difference between an RCD and a circuit breaker. Regardless of the functional purpose, any device is installed. The theoretical preparation is so weak that to a reasonable question - how does an RCD differ from a differential machine - none of them can give an explanatory answer. All sorts of versions are being expressed. Even, as a “competent” electrician once said, these are markings from different manufacturers. But nevertheless, it’s time to figure out what is the difference between an RCD and a difavtomat.

Operating principle of residual current device - RCD

Designed as a device to protect against electric shock, it performs tracking functions. Identifies differences between connected buses. By supplying electric current to the load through the primary winding of the differential transformer, it compares it with the incoming value to the secondary. Taking into account some losses, the difference in readings is determined. The reference deviation is the set leakage current. When it is minimally exceeded, the device is triggered and instantly disconnects the circuit from the supply network.

Leakage current is a specific value. It is calculated depending on the conditions of use of the RCD. Moreover, the load capacity of the line is not taken into account. The electric current in the load can be any. Only insulation resistance is taken into account. Hence the functional application. As soon as the broken insulation allows a connection between the conductor and the ground or the human body to form, the power contacts are disconnected, which de-energizes the entire circuit.

Functionality of the differential machine

By repeating the properties and operating principle of the RCD, the difavtomat accordingly protects against electric shock. Thanks to the differential transformer, it also monitors the integrity of the electrical circuit. But still, the difavtomat has additional capabilities, which allows it to be used not only for protection against electric shock.

All functions of the differential machine can be reflected in the following list:

Control and instant shutdown if the leakage current value is exceeded, the function completely duplicates the capabilities of the residual current device;
Thermal circuit protection- protects the line from connecting devices with initially superior power, as well as connecting many small consumers with a total unacceptable current;
Automatic shutdown in case of short circuit in the load- if the conductor phase is connected to zero, grounding or another phase, the protection will operate accordingly and break the dysfunctional circuit.

How to distinguish an RCD from a difavtomat by external signs

The housing of the differential circuit breaker has virtually no significant differences from the appearance of the protective switch. Installed in an electrical panel, they look similar to the uninitiated observer. Both circuit breakers occupy two mounting spaces on the DIN rail. On their front side there is a shutdown lever and a “test” button. Virtually indistinguishable automatic devices and RCDs. What the difference is can only be understood by the technical markings on the case.

However, the differences are so obvious that it is almost impossible to confuse a differential circuit breaker with an RCD:

Application of difavtomat and RCD

Depending on the purpose, certain protection devices are used. Schemes may vary. So, to control one line, it is reasonable to use a differential circuit breaker, and for several lines, it is reasonable to use a comprehensive connection of RCDs and protective circuit breakers. However, space available in the shield also limits application.

If for a single line connecting a differential circuit breaker does not create any special difficulties, then installing an RCD for several requires special attention. Connect phase and neutral to the input of the circuit breaker. The output forms two power buses. All circuit breakers that protect against short circuits and overloads are connected to the phase wire. Accordingly, the neutral wires are connected to the bus of the same name.

Before we begin to explain how RCDs and difavtomats differ from each other, we need to decipher what is meant by the names of these devices. So, an RCD is a residual current device, while a difavtomat stands for a differential circuit breaker. Those. The RCD protects us from electric current, and the difavtomat serves to protect cables, wires and electrical equipment from unacceptable currents - short circuits and overloads. So what are these devices and how are they different?

Definition

RCD- an electrical protection device equipped with a module for detecting the difference in currents passing through this device. In other words, when the differential current exceeds a certain specified value, the contacts open. An RCD typically consists of separate elements that detect, measure (comparison to a set point) residual current, and make/open an electrical circuit (disconnector), and does not contain components that provide protection to the wiring, connected circuits, or the device itself.

Difavtomat- this is an RCD and a circuit breaker mounted in a common housing. The difavtomat is used to protect electrical wiring from current leakage (corresponds to the functions of an RCD) and to protect electrical wiring from short circuits and overloads. The location of thermal protection and an overcurrent protection module in the circuit breaker guarantees the safety of the connected electrical circuit and the device itself. Thus, the difavtomat provides comprehensive protection for itself, the equipment, and the protected circuit.

Difference

An RCD differs from a difavtomat in that it does not protect the circuit and load, as well as itself, from short-circuit currents and currents exceeded due to overload. An RCD, unlike a differential circuit breaker, is a device that protects the load and circuit only when a leakage current occurs. Therefore, an RCD, like any device connected to a network, requires mandatory protection. It can be provided by a circuit breaker installed in series with the RCD. As a result, the circuit breaker will protect both the circuit and the RCD included in it from overloads and short circuits. Those. If such situations occur, the machine will cut off the power supply to the circuit. In turn, the RCD will protect the electrical circuit and the load connected directly after the RCD from current leakage (it will turn off the power). An RCD is a module that detects current leakage and an actuator in the form of a power relay.

A modern differential protection device is an assembly consisting of a differential protection module and a circuit breaker. In addition to the leakage detection module and power relay, the difavtomat usually contains an electromagnetic and thermal release.

Conclusions website

A standard RCD, unlike a standard differential circuit breaker, protects the load and circuit only when a leakage current occurs.
The difavtomat is used to protect against current leakage in an electrical circuit (similar to an RCD) and, in addition, to protect against short circuits and overloads of electrical wiring.
The RCD is equipped only with a current difference detection module and a power relay.
The differential circuit breaker consists of an RCD, a circuit breaker and usually includes electromagnetic and thermal releases.
The use of RCDs and automatic circuit breakers in each specific case depends both on the design of the electrical wiring and power supply, and on the protected device, electrical circuit, or the size and technical characteristics of the room.
The cost of a difavtomat is usually higher than the cost of an RCD.