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Difavtomats perform a double function (protect against electrical leaks and short circuits) and completely replace the set of RCD and circuit breaker. When choosing a differential, you must consider the following characteristics:
- Circuit breaker rating (A);
- Leakage at which the mechanism is triggered (mA);
- Trip characteristic (“A” or “AC”);
- Type of mechanism (electronic or electromechanical);
- Release characteristics of the machine (B or D).
But how to choose specific values? Taking the opportunity, and not for the first time turning to our electrical engineering expert, I decided to ask him these questions. Namely, the engineer, and part-time specialist in the sale of differential protection, Sergei from the AxiomPlus online electrical equipment store. And this time, although reluctantly, he carried out another educational program.
- How to calculate and determine the right automatic machine for yourself?
- Which release rating should I choose?
- Trip characteristic "A" or "AC"?
- Which type of release should I choose?
- Select the release characteristic of the machine: “B” or “C”
Characteristics of difavtomats
So, let's assume that you decide to buy a automatic machine. How to understand which option is right for you? Let's look at the main designations of difavtomats.
Modules, poles, phases.
These concepts are often confused. Let's do it this way.
- Phase is what system the difavtomat is designed for. There are only two options - 1 phase (domestic) and 3 phases.
- Polarity is the number of clamps on a difavtomat. That is, this is how many lines you need to connect. There are two-pole difavtomats (for single-phase networks) and four-wheel difavtomats (for three-phase networks).
- The number of modules is the size. For example, two-pole automatic circuit breakers (for single-phase networks) are usually made two-module (that is, they occupy 2 modules in the panel). But they also come in single-module (super compact) and three-module (usually very budget options).
If you choose a difavtomat for an apartment, 90% of the time you need a two-module, two-pole and single-phase difavtomat.
Nominal value and class of the difavtomat
These indicators answer the questions:
- How quickly will the automat operate when overloaded?
- At what current value will the automatic circuit breaker operate?
On the market you can find classes A, B, C, D. A is the fastest, D is the longest. For domestic use, mainly class B and class C are used. Why is this so? If you install a class A machine in your apartment (although it costs several times more than B and C), then every time you turn on the vacuum cleaner, the automatic machine will work. This is due to the fact that when the vacuum cleaner is started, the current in the network increases sharply for a short period of time. But class A is very sensitive and therefore will work immediately.
If you set class D, the device will not respond quickly enough.
As for the nominal value, it all depends on your tasks.
Test button
Must be present on all automatic machines. Simulates current leakage. Manufacturers recommend pressing it at least once every three months.
Trigger type
This characteristic means what currents the difavtomat reacts to.
Type A - such a device responds to alternating and pulsed current. It costs several times more than the AC type. Sometimes washing machine manufacturers recommend installing such devices on the washing line. The reason for this is that the washing machine creates a pulse current (that is, current, then not).
AC type is the most popular option. Responsive to alternating current.
Everything is simple here - if there are no special instructions or devices - install AC type automatic machines.
Leakage current
This indicator indicates how sensitive the automatic machine is. As a rule, difavtomats with a leakage of 30 mA (milliamps) are used. This is taken into account optimally for human protection - not too sensitive for false alarms, but sensitive enough to protect a person from electric shock. MUCH less often you can find 10, 100 and 300 mA difautomats. We believe that this is due to the demand for devices.
Device type of difavtomat
This characteristic means how the difavtomat reacts to current leakage. There are two main categories here
Electromechanical automatic machines.
The most popular option. As a rule, they cost more than electronic ones. Such automatic devices trigger a leak regardless of the presence of voltage in the network. They are considered more reliable solutions.
Electronic automatic machines.
This type of device reacts only when there is voltage in the network. This means that if the zero is broken, the difavtomat will not protect against current leakage. Such automatic machines are presented in the Legrand RX and Schneider Easy9 series.
In order to understand what type of automatic machine is in front of you, you need to study the diagram.
For electronic automatic devices, the operating diagram always shows a circuit board with an amplifier in the form of a triangle (this is a symbol for amplifiers according to GOST).
We recommend using electromechanical automatic machines. They are more reliable and are not much more expensive than electronic ones.
Select the release characteristic of the machine: “B” or “C”
The most popular differential models have the following release characteristics: “B” is the most popular option. Characterized by minimal response delay. Suitable for domestic use in houses with old wiring. Not recommended for networks supplying equipment with high starting currents (washing machines, pumps, refrigerators, concrete mixers, etc.). Short-term excess loads provoke the so-called. false alarm. Instantly triggers at currents equal to 3-5 rated; “C” is a universal option, a good solution for private homes. It has a longer delay before operation, so it does not respond to high inrush currents. It is recommended to select for networks with a large accumulation of powerful electrical equipment running on electric motors. Instantly triggers at a load 5-10 times higher than the rated load.
Type “B” is best used for lines without powerful consumers, and type “C” is more suitable for outlet lines with a load of 1 kW or more.
To maintain selectivity, it is advisable to set “C” at the input, and “B” at the outlet lines and lighting, so that in case of short circuits the input differential does not operate before the group ones.
Comments:
I would rather install an RCD with an automatic device than a DIF automatic device. When triggered, it is immediately clear whether the power has been turned off - a short circuit or a leak. This cannot be distinguished in DIF.
Who knows, there are single-pole DIFs? Or at least to occupy one place on the rail. Otherwise I don’t have any space left in the shield, and I need to insert a DIF
SLAVA, as far as I know, there are none. The necessary parts simply won’t fit into a single-seat machine.
The diff cannot be single-pole by definition. It must compare the phase and zero currents. If there is a difference - trim (different - different, English), it should be turned off. So, there are at least two poles.
There is a single-module differential. automatic, for example from ETI KZS-1M
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What to choose?
Experts know about the operating principle of automatic devices and RCDs. Here you cannot simply compare, talking about some device in the categories of bigger, better and stronger.
They have almost the same characteristics, if the latter also has an automatic pre-installed. This is similar to comparing a car's sets of tires for winter and summer, choosing from them the only correct option. They are needed for the same purpose, but the conditions of use are noticeably different.
First, look at the place where the equipment will be installed. There may be some minor features. For example, the shield is small, there are shortcomings in connection, and no one can cancel the financial aspect. Some criteria can be neglected, while others can be focused on.
Read here! Relay protection: what is it and when is it used. Instructions for connecting the system and features of calculating its characteristics
If basic protection of one end customer or a simple line is needed, then a difavtomat is best suited.
Choosing a differential machine for an apartment
Correct choice of differential. machine for apartments, houses
Protection against short circuits and overcurrent in electrical wiring is carried out by automatic circuit breakers (AB), and protection against electric shock to humans and current leakage in electrical wiring is carried out by residual current devices (RCDs).
The difference between a Difavtomat and a machine and RCD
The differential circuit breaker carries two protection functions AB and RCD in one device. Individual AV and RCD protection devices and differential circuit breakers have their own advantages and disadvantages for different applications.
In what cases is a differential machine chosen?
Each apartment has a sufficient number of electrical appliances. And they all must have their own individual protection. If you install separate automatic circuit breaker and RCD on an electric stove, oven, washing machine, dishwasher, refrigerator, boiler, living room, bedrooms, children's room, etc., then what size will the electrical panel be? This is the main advantage of a differential machine.
Also, if the RCD needs to be selected for a current that is 1-2 orders of magnitude higher than the rated current of the automatic circuit breaker, then the differential circuit breaker is selected only for the optimal protection current against short circuits and overloads. And so we settled on choosing a differential machine for an apartment or house. Now you need to determine the characteristics of the device in each specific case.
Selecting the optimal current. The current value of the differential circuit breaker is selected depending on the load of the electrical appliance, the lighting power or the cross-section of the electrical wiring. There are differential circuit breakers with current parameters C6, C10 (for lighting), C16, C25, C40, C50, C63, C80, C100.
How to find out the characteristics of a difavtomat
Leakage current is the main protection parameter which is expressed in milliamperes (mA) and is indicated by a symbol. If diff. the machine is placed immediately behind the meter, then the leakage current is chosen to be 300 mA for a house, or 100 mA for an apartment. For individual groups, the leakage current is chosen to be 30 mA, and for individual networks, 10 mA.
Selecting a differential machine by current
By voltage. There are differential devices for 380 V and 220 V. For a three-phase 380 V network, the device has four contacts at the top and bottom, one of which is a working zero.
Selecting a differential circuit breaker based on leakage current
Type. Devices are divided into types with leakage current AC and A. Automatic devices of type AC are used for alternating leakage current, and devices of type A are triggered by direct leakage current. Thus, diff. Type A circuit breakers are used to protect electronic devices such as televisions, computers and even dishwashers or washing machines, where AC type RCDs do not respond effectively to direct leakage current.
Zero break protection. For proper operation of the difavtomat, a 220 V network (phase and zero) is required. If for some reason a phase is lost, the device will not work, since there is no leakage current. And if the zero breaks and a leakage current appears (damp walls with old electrical wiring, breakdown of wire insulation in an electrical appliance, etc.), then the RCD protection will also not work because there is no full power supply to the electrical protection circuit.
Installation diagram of a difavtomat with protective grounding PE
There is a danger of electric shock to a person. To eliminate such a situation, the difavtomat must have protection against zero loss. If there is no such function in RCD protection, then you need to separately purchase and install a voltage relay with protection against zero loss.
Which manufacturer of difavtomats should I choose?
There is no need to skimp on protecting electrical networks and protecting people from electric shock. A high-quality protection device will last for many years. This is much more profitable than installing cheap, unreliable protection options and changing them every year. Popular brands are ABB (Swedes with Switzerland), Legrand (France), Schneider Electric (France), Siemens (Germany). These manufacturers have proven the reliability and quality of their products for many years.
It is important to install a protective device in electrical networks with a PE protective conductor. When a leakage current appears through the PE conductor, the protection will immediately operate
And if you use the working zero N instead of PE, then the leakage current will pass through the person to the ground, which is not very pleasant. The effectiveness of protection in this case will be significantly lower than in the first option.
Marking of a difavtomat: what do the icons on the case mean?
The differential automatic machine is produced in two types of modules for operation in:
- two-phase household wiring of an ordinary apartment;
- or three-phase, used in a private home.
For the first case, the difavtomat is made of a two-pole module with a phase wire input connected to its terminal “1” and its output from “2”. The working zero is connected to the “N” terminals.
On certain types of structures, the terminals at the top may be designated 1/2, and at the bottom 2/1. This means that the input and output of the phase conductor can be connected from either side.
On the left in the picture I showed the device of the difavtomat, and on the right - the designation on the diagrams that are used when drawing them in a simplified single-line version and a more detailed two-line version for a household network with a voltage of 220 volts.
The differential switch for a three-phase 380 volt network is shown in a similar way. Its design accommodates four poles.
The first three sockets on the left and top, marked “1”, “3”, “5”, are supplied with the corresponding phase circuits. They are also removed from sockets “2”, “4”, “6”. To connect the zero on the right, the “N” terminals are used.
The installation of all four manual control levers is mechanically linked. Switching occurs simultaneously, which is a prerequisite for eliminating the partial-phase power supply of consumers.
As you can see, the neutral (neutral wire) is always connected to the rightmost pole .
The design of the difavtomat and the layout of its mechanisms is shown in the figure below. Structurally, it consists of a pair of built-in blocks: on the left is a circuit breaker, on the right is an RCD.
The four-pole device is designed in the same way. It has three left blocks - automatic switches, the right one - a differential organ.
A control lever with an input and release mechanism allows you to manually switch the electrical circuit with power contacts.
The “Test” button is intended to test the functionality of the residual current device mechanism. When it is pressed, a leakage channel is artificially created corresponding to the RCD setting and the removal of power from the power contacts is checked.
When huge short-circuit currents break, the contacts of the electromagnetic release break an arc with high temperature and energy. It reaches behind the moving contact, creating a high-pressure zone from the smoke and combustion products of the surrounding air.
All this is sent into the atmosphere through the labyrinths of the arc-extinguishing chamber, where the arc stretches and fades.
It is important to understand: reliable elimination of short-circuit currents is ensured only by the joint operation of the electromagnetic cut-off with the arc extinguishing chamber.
Structurally, the residual current device and the differential circuit breaker are very similar. They are manufactured in modules of the same type, which are easy to confuse for an inexperienced user.
When the question arises of how to distinguish a difavtomat from an RCD, then immediately look at the designation of electromagnetic and thermal releases.
They are absent in the design of the RCD.
Elite models of difavtomats have an operation indication, by which one can judge the reason for the shutdown: there has been a leak through the insulation or an overload, a short circuit. This option is not available on budget products.
Installing such an indicator speeds up the search and detection of faults, repairs, and commissioning of electrical wiring after the emergency has been eliminated. The benefits are obvious.
When selecting a differential switch for your home, pay attention to the technical data marked by the manufacturer on its body.
Let's look at it in a little more detail.
Rated current: the most important parameter for selecting and connecting a difavtomat
For domestic purposes, devices are used that operate with a load normalized by currents of 6, 10, 16, 20, 25, 32, 40, 50, 63 amperes. These basic values of the household network are determined by the standard series according to GOST 6827-76.
Diphavtomats, up to 16A, are installed for lighting systems, 40 A and above - at the input. Intermediate ratings are selected for socket groups and individual powerful consumers.
The rated current limits the loads that can flow unhindered in the protected circuit. Anything above this value will simply be disabled.
On the other hand, when choosing, you should bring the sensitivity of the machine as close as possible to the rated current to the critical loads that consumers and cables and wiring can withstand.
Coarsening can lead to wires burning due to overload, and the protection will not even feel it.
In some cases, it is more convenient to select a difavtomat not according to the rated current, but according to the power of all connected consumers. There is no big difference here. The meaning of the technique is as follows:
- all household electrical appliances (lighting, tools, washing machines, refrigerators, heaters...) are marked with a power consumption rating;
- The difavtomat protects a certain socket group with them;
- all powers of devices in this group are summed up: the maximum value in watts that will load the differential switch is determined;
- this power is divided by the nominal voltage of 220V and the final load current is obtained. It is used to select the denomination of the automatic machine.
Such calculations have long been tabulated and take into account the material and cross-section of conductors and cables.
Time-current characteristic: how fast is the current cutoff
Protection of the difavtomat against exceeding the rated current is normalized by the response speed and depends on the degree of excess of the emergency value. The larger it is, the more dangerous the situation is created - the cutoff should occur faster.
However, the type of connected load, especially inductive consumers and pulse transformers, influences the performance and selection of a specific device.
Therefore, differential circuit breakers, like simple circuit breakers, are standardized according to three time-current characteristics of the current cut-off, denoted by Latin letters: B, C, D.
This means that to save wiring with a large number of electric motors and a rated current of 16 A, you should choose a connection module designated C16. The reason is as follows.
Asynchronous electric motors of refrigerators, freezers, split systems, washing machines, vacuum cleaners and other equipment, when starting, consume a current that exceeds the rated value by 3-5 times.
If the network circuit contains several devices with pulse transformers, then your choice is D16, and for normal conditions the fast type is best suited - B16.
This technique allows you to optimally select a difavtomat and avoid false alarms during operation.
Breaking capacity: what kind of beast and how to take it into account
This characteristic is also called the ultimate switching capacity (UCC). It is shown as a four to five digit number with the letter A inside a rectangle (4500A, 6000A or 10000A).
This value is the limit that limits the disconnecting capabilities of power contacts, their ability to break an electric arc and not burn out.
If you do not ensure the correct calculation of the PCS, then during the liquidation of an emergency the consequences can be fatal.
Only an electrical laboratory can accurately determine and calculate the breaking capacity of the main protections. In practice, it is generally accepted that the resistance of old aluminum wiring in buildings allows the use of modules with PKS 4500A, in new buildings with copper wires - 6000A.
When the new building is located close to the supply transformer substation, then your choice of PKS should be only 10000A.
Differential leakage current or protective device sensitivity
For automatic machines this value is usually 10 or 30 milliamps. It is quite rare to find more sensitive 6 mA products.
Inside ordinary residential premises, it makes sense to select a leakage current sensitivity of 30 mA. For kitchens and bathrooms with high humidity, it is better to choose a setting of 10 or even 6 mA. They will better ensure your safety.
Differential protection class: where even experienced electricians make mistakes
A stalemate can arise if the waveforms that exist in modern wiring are not taken into account correctly.
It is generally accepted that the main currents in a home network are sinusoidal alternating currents, and not pulsating, rectified or constant. But this is not entirely true: the ideal form of the harmonic has long been violated.
Moreover, the RCD response setting always depends on the current value.
It varies depending on the signal shape and can lead to protection failure. I outlined this issue in more detail in a separate article about the forms of currents that are created by our consumers. It is useful for you to know this.
All these nuances are taken into account by RCD manufacturers. They show the waveform with which their product can be reliably operated using letter and graphic markings.
Be careful: if you read the article I recommended, you should understand that when your apartment does not have electronically controlled appliances, which I doubt, this does not mean that your power is supplied by a pure sine wave.
Your neighbors, and all other consumers of the power supply network of the transformer substation, have already changed its shape. Therefore, the usual AC differential protection class may not work correctly in a critical situation.
I recommend choosing class A devices for connection.
A typical mistake in using an RCD instead of a category A automatic machine is to select an AC type machine, but not an A one. This is not an equivalent replacement.
Current limiting class: speed of elimination of emergency processes
The sooner an accident is resolved, the less damage it can cause to your equipment. This factor is taken into account by the current limiting class and is characterized by the response time.
The slowest machines must cut off overcurrents in a time corresponding to half the period of the standard voltage frequency of 50 hertz: 10 ms. Their manufacturers do not label them in any way.
Current limiting class 2 cuts off overcurrents twice as fast as class 1, and class 3 – three times faster.
When selecting and connecting a device, pay attention to its response speed.
The principle of selectivity: how to properly create comprehensive protection
There is an input circuit breaker on the input switchboard to the house or apartment. It protects all wiring from short circuits and overloads in the power supply. After it there are additional machines for floors or individual rooms.
The selectivity of the machines determines the sequence of switching off random emergency situations. The rules are as follows:
- If a short circuit occurs, for example, inside a microwave socket, the circuit breaker of the socket group in the kitchen must first turn off. Let's consider the case when he refused: there is no ideal technology;
- then it is the turn of the automatic switch of the floor panel to operate. But, after all, it can break;
- such an accident must be turned off by the input machine.
Such a system generates three emergency shutdown queues, eliminating false alarms. They can be created according to one of the following principles for redundancy of short-circuit failures and overloads:
- on the formation of the sensitivity of current settings, when the roughest protection is at the remote end and works last;
- or by installing machines with the same current setting, but different speed (current limiting class). The fastest ones are installed by the consumer.
There are two more ways:
- combine both methods;
- purchase a circuit breaker with the ability to adjust the selectivity of operation. There are some on sale too.
When using residual current devices, like automatic circuit breakers, you should pay attention to the selectivity of the action of leakage currents. For example, behind an RCD with a setting of 30 mA it is necessary to install a 10 mA module, but not vice versa.
If you install two identical protections in series, ensure faster operation for the one closest to the consumer. Otherwise, problems will arise with finding the location of the damage.
In this way, a protection system against electrical fires is created: a fire protection RCD with a setting of 100 or 300 mA is installed at the entrance to the house.
Is it necessary to install grounding?
In modern washing machines, the housing has a potential that is half the network potential - 110 V. Thanks to the grounding wire, this potential flows to the ground. Why is this done? The point is in the features of network filters that suppress electrical interference produced by the washing machine during operation. The device body is connected to the electrical network not directly, but through filters.
Grounding helps protect a person from electric shock if insulation damage occurs. If there is no grounding, a person touching the case feels a tingling sensation, and sometimes even more serious shocks. In a damp room, a washing machine without grounding can cause serious electrical injury, even death.
By installing a difavtomat on a washing machine, you solve two problems at once - you eliminate equipment breakdowns due to problems in the electrical network and protect its users from electric shock.
Bad 2
Interesting 11
Super 4
Breaking
There is no technology without problems. Everyone may experience them from time to time. The main thing is that this is found and corrected in time. Two-pole automatic machines are no exception in this regard.
A common problem occurs in thermal releases. It may stop working under any light load. This is very difficult for ordinary people without special education to identify. Therefore, almost all breakdowns are directly related to calling an electrician. There is no need to aggravate the situation on your own if you do not understand this issue.
Which RCD should I install on my washing machine?
The average user wants to know which protective device to install on the washing machine. Most models consume 2 kW, and this exceeds the nominal value of 10 A. Therefore, an automatic or automatic device must operate with an electric current greater than 10 A. Choose the 16 A option.
Among the important parameters of automatic protection is leakage current. The device reacts precisely to it. If the wiring is new, take the 10 mA option. For a circuit break to occur, the difference in current between phase and neutral must be 10 mA or more. If the wiring is old, use a 30 mA RCD to avoid erroneous shutdowns.
Another nuance that is important to pay attention to when choosing an automatic machine to connect to a washing machine is the manufacturer. There are two options:
- Expensive and high quality - Legrand or ABB.
- Budget - IEK.
These are the most famous companies on the market that produce protective automation. Chinese versions are cheaper, but they will not provide the reliability that European devices provide. If you select the wrong power and electric current, the plugs will be knocked out every time you start the machine.
conclusions
Photos of difavtomats always look more respectable. All options have the right to exist. But now it is customary to introduce savings everywhere, which is why they choose combined electrical appliances, which include several functions at once.
Usually, for one person who has a washing machine, refrigerator, water heater and similar appliances, a budget device is chosen. This could be a classic model from Schneider for an amount not exceeding 2,000 rubles.
An RCD will cost more for a group of people who have sockets in the kitchen, spacious bathrooms, washing machines, boilers, and lighting fixtures. All this requires separate switches. As a result, the project will cost 6-7 thousand rubles with all the consequences.
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Group consumption always leads to additional costs. The amount can reach up to 10 thousand rubles. Having dealt with electrical equipment, you can safely move on to other things. The wiring may not be changed for the next 10-15 years.
Scheme
When designing a wiring diagram for an apartment or house, there can be many options. They may differ in ease of use, reliability of operation, and degree of protection. There are simple options that require minimal costs. They are usually implemented in small networks. For example, in dachas, in small apartments with a small number of household appliances. In most cases, it is necessary to install a large number of devices that ensure the safety of the wiring and protect people from electric shock.
Schemes come in different levels of complexity
Simple scheme
It does not always make sense to install a large number of protective devices. For example, at a dacha for a seasonal visit, where there are only a few sockets and lighting, it is enough to install only one difavtomat at the entrance, from which separate lines will go to groups of consumers - sockets and lighting - through the machines.
A simple diagram for connecting a difavtomat to a small network
This scheme will not require large expenses, but if a leakage current appears on any of the lines, the difavtomat will work, de-energizing everything. There will be no light until the causes are clarified and eliminated.
More reliable protection
As already mentioned, some automatic machines are placed on “wet” groups. These include the kitchen, bathroom, outdoor lighting, and appliances that use water (except the washing machine). This method of building a system provides a higher degree of safety and better protects wiring, equipment and people.
A more complex and reliable scheme: connecting a difavtomat to every potentially dangerous device
The implementation of this wiring method will require large material costs, but the system will operate more reliably and stably. Since when one of the protective devices is triggered, the rest will remain operational. This connection of the difavtomat is used in most apartments and small houses.
Selective schemes
In extensive power supply networks, there is a need to make the system even more complex and expensive. In this option, an input differential circuit breaker of class S or G is installed after the meter. Further, each group has its own circuit breaker, and, if necessary, they are also installed for individual consumers. See the photo below for connecting the difavtomat for this case.
Selective installation diagram of a difavtomat
With this design of the system, when one of the linear devices trips, all the others will remain in operation, since the input differential switch has a delay in response.
What determines the popularity of Chinese automatic rifle models?
It is worth noting that almost all European-assembled products are distinguished by high levels of quality and reliability. The internal functionality is practically no different. The main selection criteria for the modern buyer:
- Possibility to order products online. Such a decision is in no way connected with a person’s lack of desire to go shopping. On the manufacturers' website you can purchase a high-quality product at an affordable price, which is indicated without any extra charges. And this is already a tangible benefit.
- Terminals. They come in several types and, of course, it is better to have spare ones in the house, which will be needed during repairs. They can be purchased directly from the manufacturer.
- Body shape. It may happen that the device is installed in a visible place. In this case, the appearance of the adapter will play an important role.
- The color palette of the top layer of protective coating can also vary significantly between different models.
A consumer can easily get lost among all sorts of different types and numerous new products. Expert advice and personal preferences will come to the rescue. Electricians often recommend the models they are used to working with. This means that if necessary, they can be contacted in the future. In addition, European analogues are often $25-50 more expensive than Chinese analogues.
Basic errors in connecting difavtomats
Sometimes, after connecting the difavtomat, it does not turn on or turns off when any load is connected. This means that something was done wrong. There are several common mistakes that occur when assembling the shield yourself:
- The wires of the protective zero (ground) and the working zero (neutral) are combined somewhere. With such an error, the automatic machine does not turn on at all - the levers are not fixed in the upper position. We will have to look for where “ground” and “zero” are combined or confused.
- Sometimes, when connecting a difavtomat, the zero for the load or for lower-lying machines is taken not from the output of the device, but directly from the zero bus. In this case, the switches are in the working position, but when you try to connect the load, they are instantly turned off.
- From the output of the difavtomat, zero is not supplied to the load, but goes back to the bus. Zero for the load is also taken from the tire. In this case, the switches are in the working position, but the “Test” button does not work and when you try to turn on the load, a shutdown occurs.
- The zero connection is mixed up. From the zero bus, the wire must go to the corresponding input, designated by the letter N, which is located at the top, not down. The wire should go to the load from the lower neutral terminal. The symptoms are similar: the switches turn on, the “Test” does not work, and when the load is connected, it triggers.
- If there are two automatic circuit breakers in the circuit, the neutral wires are mixed up. When such an error occurs, both devices are turned on, “Test” works on both devices, but when any load is turned on, both machines are knocked out at once.
- If there are two automatic machines, the zeros coming from them are connected somewhere further. In this case, both machines are cocked, but when you press the “test” button on one of them, two devices are switched off at once. A similar situation occurs when any load is turned on.
Now you can not only select and connect a differential circuit breaker, but also understand why it is tripping, what exactly went wrong and correct the situation yourself.
Rating of the best manufacturers
Hager
The German manufacturer produces products in a traditional silver case, with a branded blue stripe. It is worth noting that the location of the clamp terminals is very thoughtful. Ultimately, this will make subsequent installation easier. The contact status is visible on a special color indicator. It is located on the front panel, so it is easy to see through the slot on the shield. They produce high-tech models of German quality.
Advantages:
- the case is made of durable material and equipped with a wide button, which is convenient for both sealing and switching;
- The clamp terminals are incredibly reliable and have a textured surface;
- Excellent connection of conductors even in the absence of ferrules.
Flaws:
- The location of the window with the inscription is extremely inconvenient (under the window itself, which makes it practically unreadable through the existing opening).
If the device works, you will need to open the door and see exactly where the leak occurred.
Legrand
The manufacturer comes from France. The distinctive feature is not the principle of operation, but the height of the body. This ensures excellent heat dissipation. The indicator window and buttons are located on a flat platform and at an acceptable distance from each other. Subsequent service will be as comfortable as possible. The large window is located at the top, so it is clearly visible through the existing slot.
Advantages:
- the contact strips are ribbed, which guarantees an excellent connection of wires;
- color indication – double (if a seal is installed, the unit will still indicate a leak by changing the color of the indicator);
- a simple and intuitive panel; there is nothing superfluous on it that could distract the user’s attention.
Flaws:
- not detected.
It is worth noting that the company entered the market relatively recently, but has already managed to gain a strong position in the modern market. Previously, the brand produced exclusively switches and sockets.
General Electric
The American concern produces not only electrical appliances, but also many other products, including locomotives. The body shape is classic, however, the dough shape is non-standard (located at the top left). The electromagnetic release is extremely reliable and incredibly resistant to overheating. Before choosing a device, you should consider this aspect. Subsequent repairs will not require any special costs.
Electronic devices contain microcircuits that cannot withstand high temperatures. Due to this, they are cheaper than more technologically advanced and expensive models.
Advantages:
- the handles are made paired, thereby opening automatically to neutral and phase (a kind of insurance);
- The switch can be turned comfortably thanks to the wide handle;
- The manufacturer uses high-strength plastic that is resistant to significant mechanical and temperature loads.
Flaws:
- if other modules are located near the differential machine, then because of the handles it will be difficult to stretch the much-needed sealing cable;
- there is no identification window, so it is difficult to mark the line;
- the presence of a color indicator is not provided (if the location is fixed, it will not be clear whether the device worked or not).
Abb
German quality, which has an appropriate price. They do not produce budget or inexpensive models, which is why this brand tops the ratings of the most counterfeited ones. A distinctive feature of the product is the presence of an “abb” chip on the left side with a convex plug. There is also a red line on the front side of the model, and the shape of the case is very specific. The installation process can be significantly complicated if there are no auxiliary comb busbars and jumpers from the same company. Without them, connecting groups is not possible.
If there are only two automatic switches, a comb may not be needed when assembling the electrical panel. But we are talking only about one-room apartments. If there are two or more living spaces and a shield for 5 differentials, the presence of a comb tire will significantly simplify installation.
Advantages:
- the location of the test is acceptable (directly above the plug), you can press it without fear, because it is almost impossible to touch the handle;
- the presence of a double color indication (even if the button is fixed, the protection will work and the corresponding indicator will indicate this);
- presence of paired buttons.
Flaws:
- the market is full of Chinese fakes (difficult to recognize);
- there is no identification window;
- On the right side, the clamp terminals will be placed on the DS-951 series (installation may be difficult).
Schneider
This is the best product to buy based on numerous consumer reviews. The manufacturer has three main series:
| Type | Short review |
| "Brownie" | The most affordable models. Produced exclusively for the CIS by Bulgaria. A characteristic feature is the presence of a large orange button. The color indication is to the left of it. Clamp-type terminals are located on one side. |
| "Easy-9" | Average price for products. The “test” and “power on” buttons are located as conveniently as possible. They have a black color. The models do not have a color indicator, which is extremely inconvenient for subsequent use after sealing. There is no way to know if the system worked without removing the seal. In other series they are located on the sides, which is very convenient for installation. |
| "Acti-9" | The yellow latch and hemispherical buttons are a distinctive feature of the series. This is the manufacturer's highest quality product. It copes with the assigned tasks and functions excellently. It is better to buy this type of differential at the stage of building a new house. |
Advantages:
- High-strength plastic is used to make the case, which is not afraid of temperature changes and mechanical loads;
- huge assortment;
- It is worth paying attention to the cost of products that are suitable for any budget.
Flaws:
- in addition to the “brownie”, other series do not have a color indicator;
- there is no identification window;
- The contact clamps are on one side, except for the “brownie” one.
It stands for (single-module automatic machines), the design is simplified. Compared to products from a Russian or Spanish manufacturer, which use classic structural elements, they are characterized by a higher reliability index.
It was necessary to significantly reduce the dimensions of the type of release used in order for it to fit into one module. This involves installing an additional amplifier and microcircuit that cannot function normally under high load conditions. Thus, the products will be characterized by a lower degree of reliability compared to similar devices with two modules.
Iek
A Russian manufacturer that produces not only electrical appliances. He has two series of differentials:
- "AD-1". Externally there are practically no differences. The only exceptions are paired switches, which simultaneously break the neutral and phase. There is a color indication above the switches. There are also separate holes for the comb, which will be very useful during the installation process.
- "AVDT". There is a yellow switch on the case, and a color indication underneath it. The “test” button is small and gray and very comfortable to press.
Both series use an electronic release. The choice of product will depend only on the network voltage and the equipment used. It is worth noting that they can also operate in low temperatures (down to -25°C). Electronic type releases are cheaper compared to electromechanical counterparts. However, they are widely used when installing Chinese differentials.
Advantages:
- excellent service support (if necessary, equipment can be sent for repair in any city);
- three-phase differentials are offered (only Chinese manufacturers put them on stream);
- installation of a three-phase model will cost significantly less compared to an automatic machine and an RCD;
- low cost compared to European-assembled analogues.
Flaws:
- there is no identification window;
- the use of low quality plastic, which makes the case fragile;
- the use of predominantly electronic mechanisms (they are less reliable).
Operation during shutdown
Any protective device is installed for the purpose of protection, so that it will operate and turn off the power in an emergency. Let's imagine that such a situation arose. The differential circuit breaker has switched off in the control panel. What actions need to be taken?
The first step is to urgently find the cause of the shutdown. Perhaps the cause of the shutdown was a current leak, or the reason was a short circuit somewhere in the cable, or maybe the line was simply overloaded? As you can see, when a RCBO is triggered, there are three reasons at once and it is necessary to spend a lot of time troubleshooting.
When using the “automatic + RCD” combination, everything is clear. If the RCD turns off, then the fault is a current leak. If the circuit breaker has tripped, it means there is a short circuit somewhere or a line overload.
Features of integrated operation of protective devices
To understand how to install an RCD - after or before the machine, you need to understand the functionality of the installation. A good example would be a system consisting of a metering device, a residual current device, or a circuit breaker connected to one line.
The voltage from the transformer will pass through the RCD and the meter, supplied to the sockets. If there is no protection, the shutdown device burns out. The absence of a release in front of the meter will also lead to a line fire. The best option is a protective device on both sides.
According to the requirements of the PUE, two-pole modifications of machines are placed before the metering device. There is no need to place it in front of it - it is better to protect the line from the RCD to the consumers.
Criterias of choice
Having given preference to a difavtomat, you need to carefully consider the process of selecting it. Initially, you need to familiarize yourself with the performance characteristics of the product.
Rated voltage and phase pattern. Choosing the right differential machine in accordance with the required parameters is not difficult. Devices designed to operate in a single-phase network (220 V) are equipped with three connection terminals, while devices for three-phase networks (380 V) are equipped with four poles. The rated operating voltage is indicated in the passport and marked on the product body.
Current rating and characteristics
In order to ensure high-quality operation of the differential machine, it is important to choose the correct current rating and characteristics. Information about these parameters is indicated by a letter of the Latin alphabet and a number, for example, C25, which means a device with characteristics C, with a rated operating current of 25 A
The most popular differential automatic machines for apartments and private houses are products with characteristics C. When choosing a differential automatic machine based on power, it is recommended to adhere to the values indicated in the table:
Leakage current. Indicated by the “delta” symbol with a number corresponding to the rated leakage current in milliamps. The data in the second table will help you choose the right circuit breaker based on leakage current:
Important! For a water heater, washing machine, bathroom or bathhouse, you need to choose a device that operates at 10 mA. For a group line, it is enough to select a 30 mA characteristic if you decide to divide the wiring into groups
For input into a private house, to protect against fire, it is recommended to install a 300 mA difavtomat, and in apartments it is enough to use a device rated at 100 mA.
RCD class. The RCDs built into the differential circuit breaker are divided into two classes:
- A - triggered as a result of DC leakage. To connect consumer electronics consumers to the network, you should select an RCD of this class
- AC - turn off the automatic circuit breaker when AC leaks appear in the network and on electrical equipment.
Protection against neutral conductor breakage. Some difavtomats are equipped with units that disconnect consumers in the event of a break in the neutral wire. When arranging equipment protection against current leakage, it is advisable to choose just such a product. Another important characteristic is the shutdown time (denoted as Tn). It should not be more than 0.3 s.
For a person who is unsure that he will be able to choose a difavtomat himself, it is recommended to make a purchase from trading companies with a high reputation, where he should seek help from a qualified consultant. You can discuss with him the issues of an acceptable price and which manufacturer of differential automatic machines should you choose.
Finally, we recommend watching a useful video on the topic:
So we looked at how to choose a difavtomat based on power and leakage current. We hope the information provided helped you understand the choice of a suitable differential machine for your home, cottage or apartment!
We also recommend reading:
Differential circuit breaker - is connected to provide protection against electric shock, at the same time as protecting the electrical network from overloads and short circuits.
Calculation of circuit breakers
Before purchasing a difavtomat, it is important to calculate it in such a way as to ensure timely operation and protection without failure of electrical appliances.
Determining the power of the machine
The calculation of the machine according to the power of the electrical receiver is carried out when the wiring along the entire length is designed for a certain type of load. The permissible current in this case will be greater than the rated parameters of the machine.
Calculation of the rated power of the machine
To avoid doing calculations, you can:
- View documentation of household appliances.
- Review the information on the back panel.
- Use the table with average power values of devices.
| Type of electrical appliance | Power consumption, W |
| Washing machine | 2000-2500 |
| Electrically heated floor | 2000-2500 |
| Electric stove | 4500-8500 |
| Dishwasher | 2000-2500 |
| Fridge | 140-300 |
| Mixer | 250-400 |
| Hairdryer | 400-1600 |
| Iron | 900-1700 |
| Vacuum cleaner | 680-1400 |
| Fan | 2500-4000 |
| TV | 125-180 |
| Lighting | 20-100 |
Starting power may differ from rated power.
Rated current calculation
Data on the case of the difavtomat
When calculating the rated current, they are guided by the cross-section of the wire. The rated current of the machine must be less than the maximum value designed for this cable.
The machine is selected according to the minimum cross-section of wires. For example, for a copper cable with a cross-section of 1.5 mm2, the permissible current is 25 A. A machine with a value of 25 A will lead to overheating of the wiring. That's why:
- The power of the loads on the differential circuit breaker is calculated.
- The power of all consumers is calculated.
- A calculation is made using the formula for the design current of the machine I = P/U, where P is the total power of all electricity consumers U is the network voltage.
- The result is rounded.
If wiring has not been done, you can calculate the sum of all devices in the network and select a machine with a rating that matches the calculated result. The wire cross-section must be selected according to the rating of the device.
Determination of time-current characteristic
Special graphs are used to express the time-current characteristics. The curve indicates the response of the machine when the current is turned off. The dependence of the response time of the device on the strength of the current passing through it will be this indicator.
The most common characteristics are:
- B – from 3 to 5×In;
- C – from 5 to 10×In;
- D – from 10 to 20×In.
The letter indicates the operating current.
Where is it installed?
The automatic differential control is installed only on a DIN rail in the distribution panel of an apartment or house. The machine is connected to socket blocks or individual powerful electrical appliances - a washing machine, electric oven, electric oven or water heater.
A washing machine, a freezer, a pump - these devices have an electric motor in their design, so their starting power consumption can exceed that declared by the manufacturer several times. We provide a table indicating the coefficients of current increase at the beginning of operation of the device:
Duration of inrush currents in household appliances
Thus, when turned on, a washing machine can consume 12.5 kW during the first 4 seconds, and if the automatic machine for it is not designed for such power, it will knock out every time it is turned on. But this does not mean that you need to choose a differential automatic machine with a power of 12.5 kW!
Application
The differential switch must be installed in single- and three-phase networks to increase the safety of the network for people and electrical equipment. It will protect even if the wiring insulation is damaged.
You can order differential automatic machines from different manufacturers in the store 21vek-220v.ru. We offer favorable conditions, a wide selection of reliable equipment, accessories, and components. Before purchasing, you can consult with our managers, find out the differences and features of automatic machines from different manufacturers, ask questions, get information about terms, delivery methods, and payment. We deliver orders to all regions of Russia. Call us at +7 (916) 856-69-17.
Operating principle and design
The differential circuit breaker provides protection for electrical wiring on site from short circuits, overloads, and differential currents. By installing a difavtomat instead of the initial machine, you can practically protect both yourself and the electrical wiring in the house.
Dielectric material is used in the manufacture of the case of difavtomats. Structurally, they look similar to an RCD or circuit breaker, only they are larger. There is a latch at the bottom for installation on a DIN rail.
A differential circuit breaker is a device capable of operating in RCD mode or as a regular circuit breaker. To connect the device to the electrical network, you must turn the control switch to the “on” position. The device has clamp terminals for connecting input and output lines.
The difavtomat consists of two parts. The first part, the protective one, is nothing more than a differential protection module. Its main task is to analyze the leakage current (differential current). The second part, the switch, is used to mechanically break the power line in case of emergency situations. Let's consider the principle of operation using the example of an ABB differential machine.
The protective part operates on the RCD principle. The main element is the transformer; it consists of a toroidal core with two windings. Flowing through the circuit in the forward and reverse directions, the current creates its own alternating magnetic field in each winding, the magnetic fluxes of which are equal in magnitude but different in direction. As a result, the resulting magnetic flux in the core is zero.
If somewhere on the electrical line there is a violation of the insulating layer or the equipment body is under a potential difference, current leakage occurs in these places when touched. As a result, the balance of magnetic fluxes is disrupted and, under the influence of the field, an electromotive force (EMF) is induced in the secondary winding. When an EMF appears, a current appears that acts on a relay connected to the power contacts.
To check this part of the device, a button is displayed on the front surface that simulates the appearance of a leakage current. It is usually labeled "Test". If you press it, the electrical circuit will break. Manufacturers recommend checking the device at least once a month.
The second part works as follows. Current is supplied to the solenoid coil, and from it to the bimetallic plate. The plate has the form of a strip of two pressed metals with different coefficients of linear thermal expansion. The plate and solenoid are called releases. There are two conditions under which a circuit breaker will disconnect an electrical circuit: overload and short circuit.
In overload mode, shutdown occurs using a bimetallic strip that can bend under the influence of heat. As power consumption increases, the current increases. As a result, the plate heats up, changes shape and breaks the contact. Accordingly, the electrical circuit is broken. The amount of current at which the plate breaks the contact is set at the manufacturer.
In short circuit mode, the solenoid principle is used. When the magnetic field increases, the solenoid is set in motion, which breaks the electrical circuit. To dissipate the spark that occurs when the circuit breaks, the design uses an arc suppression chamber. Dispersing it on parallel plates standing in it.
Thus, the main parts of the structure can be noted:
- current terminals;
- release:
- control lever;
- release adjusting screw;
- arc suppression chamber;
- magnetoelectric relays;
- differential transformer.
The residual current device is available either electromechanically or electronically. The difference between them is that the first type does not require additional power, since the current to operate the relay is taken from the industrial network. To obtain the required amount of current, the transformer is made large, and accordingly the machine itself has larger dimensions than an electronic one. Electronic devices are supplemented with a signal amplifier; the detected leakage current, passing through it, increases its value.
This design is typical not only for the ABB automatic machine, but also for other manufacturers.
When the RCD does not protect
The RCD will not react when a person or animal comes under voltage, but no ground fault current will occur. This case is possible when touching simultaneously the phase and neutral conductors, which are under the control of an RCD, or when completely insulated with the floor. RCD protection in such cases is completely absent. An RCD cannot distinguish the electric current passing through the body of a person or animal from the current flowing in the load element. In such cases, safety can be ensured by mechanical protection measures (full insulation, dielectric casings, etc.) or complete de-energization of the electrical device before its technical inspection.
Therefore, the RCD is always connected in series with the machine. These two devices work in pairs: one protects against leaks, the other against overloads and short circuits.
How does an RCD machine work?
The well-being of household appliances in our homes often depends on worn-out electrical substations that are not designed for heavy loads. One power surge is enough to lose all electrically powered devices in one fell swoop. To save washing equipment from the vagaries of electrical networks, it is provided with a separate RCD. It consists of:
- housings;
- transformer;
- chain breaking mechanism;
- self-diagnosis mechanism;
- electromagnetic cut-off - it is available in the latest generation models.
Triggering occurs at critical loads, the machine, opening the circuit, stops the flow of electric current - people and equipment are safe.
A dangerous situation will occur, for example, if a person touches exposed wires or if water gets on him. The automation, when activated, prevents electric shock and damage to expensive equipment. The sensor can be triggered many times and, unlike fuses, does not need to be changed.
Operating principle and operation methods
The operating principle of the difavtomat also combines the operating principles of a circuit breaker and an RCD. To protect against short circuit currents and overloads in the network, the difavtomat is equipped with electromagnetic and thermal releases, and for protection against leakage current - with a differential transformer and a tripping coil.
If a person comes under the influence of current in the section of the circuit protected by the automatic circuit breaker, a trip will be triggered against the appearance of leakage current. In a differential transformer, the balance of magnetic fluxes will be disrupted and the disconnecting coil will react to this instantly.
Occurrence of leakage current
In the event of an overload of the electrical circuit, the shutdown work will be performed by a thermal release, which is structurally and nominally no different from the thermal releases of conventional circuit breakers. And if a short circuit current occurs in the circuit, a magnetic release will do its job, which is also no different from the magnetic releases of automatic circuit breakers.
Location of magnetic and thermal releases
Depending on the installation scheme of difavtomat, selective and non-selective operation methods are distinguished.
The selective circuit involves the use of a difavtomat with the designation S on the front panel, which actually means “selective”.
The selective installation scheme is implemented by installing one difautomatic switch (selective) at the input (central distribution board, electrical panel on the staircase, etc.) and several non-selective difavtomats in the outgoing circuit. One for each site.
Input difavtomat and three outgoing sections of the circuit
This installation scheme is preferable due to the fact that if an accident occurs in any of the three protected areas, the non-selective automatic circuit breaker will switch off, while the main one will remain on. This method of operation provides a significant reduction in the risk of disconnecting all consumers at the same time.
The non-selective installation scheme is implemented similarly to the previous one, but with a significant difference. The incoming difavtomat is not of a selective design, but the same as the outgoing difavtomats. In the event of an accident in any section of the circuit, the difautomatic circuit breaker protecting this section, as well as the input difautomatic circuit breaker, will be switched off, which, in turn, will lead to the shutdown of all consumer groups.
Functionally, a non-selective circuit performs the protection correctly, but is operationally impractical.
Installation of a selective protection circuit is preferable.
Install the best automatic circuit breaker or RCD separately
- Based on the cost, it does not matter whether you buy an RCD or an automatic device. If the choice is made on more affordable Chinese automation, then the final decision will be entirely up to the buyer.
- The Chinese manufacturer is ready to offer both high-quality three-phase and single-phase differentials.
- Installation of automation and RCD will cost $50 or more. The advantage of the differential is that it has one less module (DIN rail). However, from the point of view of economy, it is recommended to purchase a larger shield with a significant margin.
- In Europe, a separate device is often installed for each phase, so the demand for three-phase models is extremely low. Accordingly, the range of such products leaves much to be desired. Due to the fact that such devices are not in use, the cost of their production is much higher, and manufacturers prefer to make them exclusively to order.
- If there is trust in one of the many brands, then the search for a suitable product will come exclusively from the existing assortment.
- There are no fundamental differences between single-phase models. An exception may be a factor such as dimensions. Their cost is approximately the same, so a person can spend a certain amount both on the purchase of a machine gun and a set of RCDs.
Additional recommendations
Pay attention to the “Test” button, with which you can test such a protective device for correct operation. It is not always necessary to install a differential circuit breaker into the electrical network of a house or apartment. And if the installation is already done
It is better to carry out installation on socket groups. Lighting, as well as the circuit that powers the electric hob, are not equipped with this device. The PUE rules state that difavtomats must be installed in networks where there is a “PE” grounding loop.
Pay special attention not only to the choice of differential machine, but also to its proper installation. This is what most often determines how the entire electrical network will work and how safe it will be.
Therefore, the assembly of the switchboard should be carried out by a professional electrician. Although it is not difficult to carry out this process yourself.
Connection diagrams for difavtomat
How to connect an RCD in a single-phase network without grounding
How to connect a difavtomat
Let's start with installation methods and the order of connecting conductors. Everything is very simple, there are no special difficulties. In most cases, it is mounted on a dinrail. To do this, there are special protrusions that hold the device in place.
Dinrail mount
Electrical connection
The difavtomat is connected to the electrical network using insulated wires. The cross section is selected based on the nominal value. Usually the line (power supply) is connected to the upper sockets - they are signed with odd numbers, the load - to the lower ones - signed with even numbers. Since both phase and zero are connected to the differential machine, so as not to confuse it, the sockets for “zero” are labeled with the Latin letter N.
The connection diagram for the difavtomat is usually on the case
In some lines you can connect the line to both the upper and lower sockets. An example of such a device is in the photo above (left). In this case, numbering is written on the diagram through a fraction - 1/2 at the top and 2/1 at the bottom, 3/4 at the top and 4/3 at the bottom. This means that it does not matter whether the line is connected from above or below.
Connecting the difavtomat on the distribution panel
Before connecting the line, remove the insulation from the wires at a distance of approximately 8-10 mm from the edge. At the desired terminal, slightly loosen the fixing screw, insert the conductor, and tighten the screw with sufficient force. THEN the wire is pulled several times to make sure that the contact is normal.
Functionality check
After you have connected the difavtomat and supplied power, you need to check the functionality of the system and the correct installation. First, let's test the unit itself. There is a special button for this, labeled “Test” or simply the letter T. After we have switched the switches to working condition, press this button. In this case, the device should “knock out”. This button artificially creates a leakage current, so we checked the operation of the difavtomat. If there was no operation, you need to check the correct connection; if everything is correct, the device is faulty
If the automatic machine works when you press the “T” button, it is operational
Further testing is to connect a simple load to each outlet. This will check that the socket groups are connected correctly. And the last thing is the alternate switching on of household appliances, which have separate power lines.
Main settings
To understand how to choose a differential machine, you need to understand its characteristics. For installation in a residential building, the differential circuit breaker must be turned off when the differential current is no more than 30 milliamps. This is a general requirement imposed by the electrical installation rules (PUE).
This meaning is justified. A direct current of 50 mA and an alternating current of 10 mA are considered dangerous for the human body.
The second parameter by which the automatic machine is selected is the rated current. It must correspond to the maximum current value in the protected section of the circuit. This parameter depends on the amount of load and the conductor used. The same parameter is taken into account when protecting against short circuit (short circuit).
Unacceptable mistakes when purchasing
The device must be connected in accordance with the specified diagram
. To buy a high-quality automatic machine, it is important to avoid mistakes:
- Installing a device with a damaged housing - dents and cracks lead to breakdowns due to displaced internal components.
- Failed test in the store - the functionality of the devices is checked at special stands.
- Selection of the device is not according to the diagram - the machine will not correspond to the likely loads and will simply burn out.
- Using wires with an inappropriate cross-section - there may be risks of short circuits and burnouts of electrical appliances.
To choose the right differential device, you will need to study the markings, technical characteristics and carry out a test right in the store.
