Circuit breakers (AB) are devices that are mandatory for any home electrical network to ensure the safety of its operation. Almost everywhere they replaced the fuses so common earlier - the so-called plugs. It is understandable: automatic machines (as AB is usually called in colloquial speech) are much more convenient to use, more compact, and in terms of protection reliability they are still much higher.

But sometimes it happens that the circuit breaker with some stubborn constancy, and, according to the owner of the apartment or house - for no apparent reason, refuses to work in the on position. That is, as they say, he regularly knocks out. Often this leads the owner to the idea of ​​the need to replace the circuit breaker, moreover, with an increase in the operating current rating. Stop! This is a fundamentally wrong and even extremely dangerous decision! First you need to figure out the reason, find out why the machine knocks out. It just doesn't happen that way. Yes, there is a small chance that the AB itself is faulty, but most often it is a signal of serious problems in the wiring or in the devices connected to it. That is, the machine, in fact, fully performs its task. And with its shutdown, it seems to remind the owner - “Deal with the cause!”

The main functions of the circuit breaker, its basic structure and principle of operation

This publication is certainly not intended for professional electricians. Its purpose is to show the most ordinary person the possible reasons for the operation of the circuit breaker and "arm" him with the necessary stock of knowledge to identify and eliminate deficiencies. Therefore, it will be useful to first briefly familiarize yourself with the device of the machine - it will be easier to understand how it works and why it can be knocked out.

So, the vast majority of modern circuit breakers designed for installation in household networks are a compact modular device for mounting on a DIN rail. The whole device is assembled in a plastic case of a characteristic rectangular shape. On the front side of the machine there is a power lever, a marking with the main operational characteristics of the device is applied. On the back there is a special groove and a latch for mounting on a rail.

There are screw terminals at the top and bottom for connecting wires when installed in a home wiring diagram. The number of pairs of contacts can vary - from one to four. Accordingly, the switches themselves, according to this criterion, are divided into one-, two-, three- or four-pole ones. In a household single-phase network of 220 volts, a two-pole one is more often used - at a common input, and a single-pole one - on separate lines. Devices with three or four pairs of contacts are usually designed for operation in a three-phase 380 V network.

The dimensions of the machine are strictly standardized, and depending on the number of poles, it can occupy from one to four module-places on the DIN-rail of the switchboard (cabinet).

What is the purpose of the circuit breaker?

• One function of it is quite obvious - it can work as a normal switch. That is, if necessary, depending on the installation location in the general scheme, the owner has the opportunity to turn off either the entire home (apartment) electrical network, or its separate section. This is often required for preventive, repair, electrical work. The function, of course, is important, but still does not determine the essence of the operation of this device.
• The second task, and already a safety plan, is to protect the home network (or a certain section of it) from rebooting. Alas, many consumers of electricity do not at all think about the fact that any conductor has a certain limit on the current it conducts. And the picture, when several fairly powerful electrical appliances are turned on at once through a whole “cascade” of extension cords and tees, can be seen quite often.

Too high current in the wiring causes it to heat up, which leads to the appearance and fire of the insulation, plastic housings of sockets or connected appliances. And this is one of the most common causes of fires.

A properly rated circuit breaker is designed to prevent such a situation. If the maximum load current in the line is exceeded, after some time, it will be de-energized.

• The third task is the instant opening of the circuit in the event of a short circuit in the network. Worn, insufficient or previously melted insulation, violation of wiring rules in switchboards and boxes or sockets, malfunctions in connected electrical appliances - all this can lead to the fact that the phase wire closes with zero without load.

The danger of a short circuit is difficult to exaggerate. The current in a closed circuit reaches values ​​​​of several thousand amperes, which, of course, no wiring can withstand. That is, if the circuit is not immediately interrupted, large-scale melting and ignition of wiring and appliances are possible. And this is already a practically guaranteed fire with very deplorable consequences.

This means that the task of the machine is to respond to a short circuit by breaking the circuit in the shortest possible time, measured in milliseconds, in order to prevent a large-scale accident.

The design of the circuit breaker is precisely designed to perform all these three tasks. Let's take a look at its device, and how it works in emergency situations.

So, at the top and bottom of the circuit breaker there are screw terminals (pos. 1) for connecting the incoming and outgoing wires to the load side. In the illustration, just for the sake of compactness, the instrument is shown horizontally. In fact, the side on the right in the figure will look up. And most often it is to this terminal that the lead wire is connected.

The input terminal is connected to a fixed power contact (pos. 2). In tandem with it, a movable power contact (pos. 3) works. It is the closing and opening of this pair that provides either switching or breaking the circuit. That is, the illustration shows that in this case the machine is in the off position - the contacts are open.

Internal switching in the circuit breaker, in addition to current-carrying metal parts, is carried out using powerful flexible conductors (pos. 4).

On the front side of the machine there is a power lever (pos. 5). Most often, its lower position corresponds to turning off, the upper - turning on the device.

The lever is mechanically connected to a special mechanism, which is a combination of levers, springs and stoppers (pos.6). When the lever is moved to the upper position, this mechanism ensures the closing of the movable power contact with the fixed one. And this contact is in a spring-loaded state, that is, when exposed to the stopper under the action of the spring, the contacts will automatically open.

But this stopper, which holds the contacts closed, can be acted upon in three different ways. Firstly, simply by moving the lever to the lower position, that is, when manually turning off the machine. And secondly, tripping can be caused by any of the two releases located inside - thermal or electromagnetic.

The electromagnetic release (pos. 7) ensures the operation of the machine in case of a short circuit. It is a coil, the turns of which are part of the total value of the passage of current through the switch. The device is made on the principle of a solenoid, that is, a spring-loaded metal core is placed inside the coil, which is mechanically connected to a movable power contact.

When current normal for the mains current flows through the coil, the generated electromagnetic flux is insufficient to overcome the spring force and retract the core. But if a short circuit occurs in the network, then the strength of the passing current instantly increases hundreds of times. Accordingly, this is accompanied by an instantaneous increase in the magnetic flux created by the coil. The core of the solenoid is sharply retracted, which leads to the failure of the lever mechanism from the stopper and the rejection, under the action of the spring, of the movable contact from the stationary one. It takes longer to write and read, but in fact, in a split second, the chain breaks.

True, they usually try not to bring it up to hundreds and thousands of amperes - the operation of an electromagnetic instantaneous release is usually calculated for a certain excess of the passing current relative to the specified rating. According to these indicators, circuit breakers are divided into classes according to the so-called time-current characteristic, denoted by Latin letters. In a home network, the following classes can be applied:

• B - operation when the nominal current strength is exceeded by 3 ÷ 5 times;
• C - 5 ÷ 10 times;
• D - 10÷12 times.

The tripping time depending on the size of the overcurrent is determined by special graphs.

Typically, class B is used to protect specific leased lines. Several lines can be combined and protected in a panel already with a class C circuit breaker. Class D is more suitable for powerful equipment with electric motors. In domestic conditions, they are used infrequently.

Such a distribution of machines by class and recommended installation site, by the way, also provides the necessary selectivity. That is, for example, in case of malfunctions on a single line, only its automatic machine can work, and the more “senior in rank” will remain in the on position, ensuring the normal operation of the remaining sections. It is clear that this greatly simplifies troubleshooting in the event of frequent protection operation.

The thermal release (pos. 8) is designed to ensure automatic shutdown when the permissible load current is exceeded. It is a bimetallic plate, which is a section of the general circuit of the current passing through the machine. If the current strength is within the specified rating, the plate is stationary. But when an excessively large load is included in the circuit, then by increasing the current strength, resistive heating of this plate begins. Due to the bimetallic structure, it begins to bend when heated. And at a certain moment, the latch holding the lever mechanism in the on position will move out of place. And again, under the action of the spring, the fixed and movable power contacts will open.

True, here the operation does not occur instantly, but with a certain delay. That is, in the event that the excess current will be noted for a certain time. When assembling the circuit breakers, they are calibrated - for this there is a special adjusting screw (pos. 9). But after assembly, this screw becomes inaccessible, and the user will not be able to bring down the factory setting.

Such a delay is necessary at least for the fact that during the start-up of many devices there are very significant current surges, which then returns to nominal. This is especially true for appliances and household appliances equipped with electric drives - power tools, refrigerators, pumps and more. And so that the machine does not react by turning off for each short-term start, such an opportunity is provided.

Breaking the contact at high currents is usually accompanied by the appearance of an electric arc. So that it does not cause damage to the machine, it has a special arc-extinguishing device (pos. 10). This is a separate chamber with a number of parallel metal plates installed in it. The arc breaks against them, loses its strength and becomes unable, for example, to melt the case or other internal parts of the switch. The gases formed during the burning of the arc are removed through a specially provided window (pos. 11).

Finally, on the back of the machine there is a shaped groove for mounting on a DIN rail, and a movable latch that ensures secure mounting on it (pos. 12).

We hope that with the device of the automatic switch, the reader has clarity. You can proceed to consider the reasons for its frequent operation.

Why might a circuit breaker trip?

First of all, one should not perceive the operation of the machine as a kind of "tragedy". If only because he was reassigned for this. And in most cases, this device, by turning it off, saves the home electrical network and devices connected to it from large-scale accidents that can result in very serious consequences.

Next, troubleshooting will be greatly facilitated if the home network is properly organized. We are talking about the so-called selectivity of the installation of machines. That is, all internal wiring should ideally be divided into separate lines, each of which is protected by its own AB with a correctly selected rating.

The commercially available lines of circuit breakers can have a rated current of 6, 10, 16, 20, 25, 32, 40, 50 or more amperes. It is important to choose the right model for each group. So, for example, at the entrance to an apartment or a small private house, a paired two-pole machine 25, 32 or 40 amperes can be installed (depending on the cross section of the wires at the input). Further, separate lines are organized for the most powerful home equipment (stove, oven, washing machine or dishwasher, etc.), protected by their own machines with a rating of 16 amperes (this results in a load power of 3.5 kW). Similar lines are laid on the outlet groups located in the rooms and in the kitchen. And separate lines combine lighting fixtures - there is enough machine with a rating of 10 amperes.

What is achieved by this? If a particular line is knocked out, and the rest continue to work in normal mode, then the troubleshooting area narrows sharply. Or, for example, the introductory machine was knocked out, but at the same time the remaining ABs with a lower trip current rating remained on - with a high degree of probability it can be assumed that the reason for the operation lies directly in the switchboard.

One more important note. It is not enough to install a circuit breaker with a rating adequate to the connected load. The cross section of the wires on this line must also correspond to the same load. Otherwise, if, for example, a 16 amp machine is installed, but it is connected to a line where an aluminum wire with a cross section of 1.5 mm is laid, the protection may not be able to cope with the task. At least until, due to overload, the wiring insulation begins to melt, followed by a short circuit.

Well, now - directly to the reasons for the operation of the protection.

Line overload

This is perhaps the most common cause of circuit breaker tripping. And this situation only means that the device conscientiously coped with its task.

And the origins of the cause lie in the improper organization of the home electrical network or in the ill-conceived operation of household appliances. It happens that too many devices are connected to one outlet group at the same time. The total load, and hence the current in the line, exceeds the nominal one, and the thermal release is activated in the machine, thereby protecting the line from emergency overheating.

At the moment the machine is turned off, you should immediately see which line is overloaded (if it is organized), and what specific load was connected to it at that time. As a rule, the picture is visual. And when one of the devices is turned off, the knocking out of the machine stops. True, when you turn it on again, you have to give a pause of several minutes - the bimetallic plate of the thermal release must cool down, otherwise the machine simply will not turn on.

So, how is this problem solved.

• The first, of course, will be measures, so to speak, of an “administrative plan”. That is, you should understand yourself and explain to everyone at home how and when you can connect powerful household appliances at the same time. Try to space the devices that you can’t do without into different socket groups. Or even just keep in mind that, for example, if something is being cooked in an electric oven, you should not turn on a washing machine or a powerful water heater at the same time. In a word, prioritize the use of certain devices, the simultaneous operation of which leads to overload.
• The second way to solve the problem can be to purchase a circuit breaker with a rating one step higher (for example, instead of 16 - 25 amperes). But this is possible only if the cross section of the laid wires allows, as already mentioned above. If the cross section is insufficient, then the problem will only get worse and lead to even more trouble.
• Hence, the third solution suggests itself - this is a major overhaul with replacement with high-quality cables with a sufficient cross-section of copper conductors. This approach becomes especially relevant in houses or apartments where old aluminum wiring is still preserved, which is completely unsuitable for the current level of electricity consumption.

If the wiring does not allow you to install an automatic machine of a larger denomination, and the immediate plans of the owners do not yet include a major reorganization of the home electrical network, only the rational distribution and use of the load remains. And, interestingly, in our time it can be solved, so to speak, at the “hardware level”. We are talking about special devices called load priority relays.

Such a device becomes especially relevant if the power limit allocated to an apartment or house is insufficient to simultaneously turn on all installed equipment. That is, there is a frequent knocking out of a common automaton at the input.

It works like this. Household appliances are pre-distributed according to their priority destination. That is, in the first group, let's say, those are allocated, the shutdown of which is undesirable under any conditions. Further, depending on the number of possible lines on the relay, other groups are also “staffed”, and the priority of each subsequent one is less than that of the previous one.

If the allowable load exceeds the set rating, the group with the lowest priority will be turned off. If this is not enough, the next line will also be switched off. But the most important devices will remain in operation, and you can not be afraid of overheating of the wiring. When the load normalizes, the relay will automatically turn on the lines in reverse order.

The operation of the load priority relay, of course, requires a separate detailed consideration. And the publication on this topic will definitely appear on the pages of our portal.

Failure of household appliances

Another situation - the connected load is clearly adequate to the nominal value of the machine. Nothing indicates the possibility of overloading the line. But the defense works with "unshakable stubbornness."

The reason may be a malfunction of the connected (pluggable) household appliance. His electrical circuit could have malfunctioned, leading to a short circuit.

It is not difficult to identify such a deficiency. First of all, you should, again, detect what exactly was connected to the power supply at the time the protection was triggered. After that, all these devices are turned off. Next, the machine starts up - and if the operation did not occur, then we can say that the accident site has already been localized in a certain way.

The next step is to sequentially connect the previously turned off devices to the power supply. And, of course, the “behavior” of the machine is being monitored. The device, the connection of which to the outlet will cause the protection to operate, obviously has internal malfunctions and needs to be repaired. And its operation will have to be abandoned until the troubleshooting.

So you should check all the disconnected devices - the picture should be outlined in complete clarity. But when checking, do not forget about increased security measures. Since there are reasonable assumptions about the malfunction of some device, a phase breakdown on its case is not at all excluded. That is, special care must be taken to avoid electrical injury.

home wiring defects

In the event that the entire load on the line is turned off, but the machine knocks everything out early, the reason may lie in a wiring fault. Here everything is already somewhat more complicated - you will have to tinker a lot to find the defective area where the short circuit occurs.

They usually start with sockets and switches. When the line is off, the covers are removed from them, and then, first of all, the condition of the terminals is checked. It often happens (and more often if the wiring is aluminum) that the contact is weakened, sparking occurs on it, the insulation burns, from where there is only one step to a short circuit. And tightening the contacts can solve the problem.

The weakening of the spring metal contacts of the socket due to their wear can also lead to this. The issue is resolved by installing a new outlet. In this case, it is necessary to get rid of the burnt ends of the wires with melted insulation.

What to do with a broken outlet?

The state of the outlets must always be monitored - it is easier to identify the problem at the initial stage and prevent its development than to then "rake" the possible consequences. How to diagnose problems and - read in a special publication of our portal.

Lighting devices should also be checked immediately - short circuits also occur in their internal wiring. The defect can also lie in the cartridge - burning of the contacts or even a short circuit at its terminals.

If the inspection of sockets, switches and lamps did not give anything, we proceed to work with junction boxes. All wire connections should be checked very carefully - broken contacts in the twists or weakening in the terminals lead to sparking, overheating of the conductors, melting of the insulation and, as a result, a short circuit. It happens that the electrical tape, previously used to isolate the twists, is unwound, for example, due to an earlier flood from the upper neighbors. And there should definitely not be bare sections of wires in the junction box.

If everything is in order here, you will have to look for a damaged section of hidden wiring. To begin with, we must try to remember whether, shortly before the accident was detected, drilling of the wall (hammering nails into it) was not carried out. It happens that such actions without prior "reconnaissance" violate the integrity of the wiring or its insulation, which leads to short circuits.

Troubleshooting hidden wiring is best done using a special tool. If it is not there, then you have to disassemble the connections in the junction boxes and ring each section of the network individually, identifying the place or, or the short circuit of the conductors. And if there is no experience in such operations, then it is better to immediately call a specialist.

Well, if a damaged area is identified, nothing will help the case except by replacing it.

Video: Possible causes of frequent tripping of the circuit breaker

Other possible cases of operation

In addition to those mentioned, there may be other reasons for the activation of the protection. They are not so common, but it does not hurt to know about them.

• It happens that an automaton with a low operating current rating (6 or 10 A) turns off at the moment the incandescent bulb burns out. At the moment when the hair breaks, an electric arc can form, and this will be perceived by the switch as a short circuit.

There is no defect in this, and no special measures are required. It's just that the time has come to abandon incandescent lamps and switch to more modern and economical light sources.

• Even before all the above operations, it always makes sense to immediately check whether everything is in order with the circuit breaker itself. Specifically, whether the wires in its terminals are well tightened.

If the terminal is not tightened enough, sparking is not excluded, which leads to heating first of the metal contact, and from it, of the bimetallic plate of the thermal release. Hence the activation of the protection. But it’s better that way than the case ends with such high heating that it starts to get dark, and then the body of the device itself melts.

By the way - a fairly common defect when using aluminum wiring. By itself, this metal is very ductile, and at constant pressure of the screw (plate) of the terminal, it begins to “sag”. That is, the contact deteriorates over time by itself. This requires regular tightening, which, of course, is forgotten. So if aluminum wiring is still used in a house or apartment, one of the priorities should be the reconstruction of the home electrical network, replacing aluminum with copper.

Which cable should be used for home wiring?

According to current regulations, wiring in residential buildings should be carried out only with copper wires. Where aluminum has been preserved, sooner or later a major replacement will still have to be carried out. A special publication of our portal will help you deal with the choice.

• Finally, if a thorough check of the home network and connected devices still does not reveal any defects, we can talk about a malfunction of the circuit breaker itself. It is clear that we are talking about a hidden malfunction - if the case is melted on the machine or, say, the lever is broken off, then it must be replaced a priori.

And the reason for the covered defect of the machine often lies in the desire of the owner, as they used to say at the Sukharevsky market in Moscow, "to buy nickels for a penny." That is, to purchase a high-quality device for minimal money. Alas, this is not usually the case in real life.

The circuit breaker is, without exaggeration, a safety device - your personal, your family members, home, all acquired property. Does it make sense to save money in such matters? Is it possible in your right mind to buy such a device cheaply from your hands or in a Chinese online store where no one can guarantee the quality of the product and the correctness of its work?

And even in a normal salon-shop, attention should first of all be paid to slot machines from well-known manufacturers that have proven the high quality of their products. Alas, not all is well with some brands.

Among domestic manufacturers, the Kontaktor brand can be distinguished, which, by the way, belongs to Legrand, which speaks for itself. KEAZ automatic machines are also a good solution in terms of price and quality ratio. You can find a lot of positive reviews about the products of the young Russian company DECraft. But for IEK machines, despite their affordability and a wide range of models, there are more complaints from users, alas. than enough.

We will complete the publication by posting a video that shows a comparison of circuit breakers.

Video: Circuit breaker - which brand is preferable, "Schneider" or "IEK.

Tripping of the circuit breaker can be caused by many different reasons, ranging from a malfunction of the product itself to a short circuit in the wiring. You can independently determine why the power trip mechanism is triggered, and it will not be difficult at all even for an inexperienced electrician. Next, we will tell the readers of the site why the machine knocks out in the shield and what to do to solve the problem!

Network congestion

The most common reason a circuit breaker (AB) trips is because it just did its job - protecting the wiring from overloading and further failure. When we considered, we said that each model has its own rated trip current: 6, 10, 16, 25 A, etc. Now, if you simultaneously turned on several powerful electrical appliances, the current of which exceeded the setting, do not be surprised why the circuit breaker in the house knocks out. For example, you have a 16A machine on the panel (a classic situation for old wiring) and at one moment you turned on the washing machine, air conditioner, electric kettle and boiler. The load on the network increased markedly, as a result of which the AB turned off, thereby protecting the electrical wiring.

There are several ways to solve the problem. The first and simplest is to turn on powerful household appliances in turn so that it does not arise. The second is to replace the machine with a 25-ampere one. This is allowed to be done only if the wiring can withstand the load (copper, conductor cross section of at least 2.5 mm 2). The third, most reliable - to a new one that will be able to withstand powerful household appliances.

The reason why the machine knocks out is intelligibly explained in the video:

What to do if AB trips under load?

We draw your attention to the fact that after the machine knocks out, if it is with a thermal release, it will not work right away. This is due to the principle of operation of the product. When the mechanism has cooled down (the time may reach several minutes), try re-cocking the lever to the “On” position.

Appliance malfunction

If the machine knocks out often and at about the same time period, it is highly likely that one of the electrical appliances is faulty. For example, if you notice that the circuit breaker trips when you turn on the washing machine, electric stove or water heater, turn off this technique and see how the device behaves without electrical appliances. Doesn't work? You need to look for a malfunction in one of the connected "culprits". About that, we told in the corresponding section of the site.

You can quickly find faulty equipment using the elimination method. Disconnect all plugs from sockets and reconnect one by one. On a device that has a short circuit, the circuit breaker will trip under load.

If you disconnected all the equipment from the network, and the machine turns off, then it may be in the wiring. What to do in this case, we will tell further.

Short wiring

Another reason why AB often knocks out is. The phase in some place touches zero, as a result of which a short circuit occurs and the machine performs its second protective function - short circuit protection. If all consumers are disconnected from the network, and operation occurs, you need to completely. This case takes quite a long time and, in addition, you need to be careful to find a malfunction.

First of all, you must disassemble all the sockets and light switches, check the quality of the wire connections to the terminals. If the wires dangle, the screws need to be tightened. After the outlets, go to the junction boxes. Make sure it's of good quality, there are no bare areas that can short out. After the boxes, you need to move on to the lamps. Very often, novice electricians forget to check the chandeliers if the machine knocks out without load. The verification technology is similar to sockets - you check the reliability of the connections.

Last but not least, you need to check the wiring, which is hidden in most houses and apartments (in the wall). In this case, it is best to use a special device that can quickly and accurately find a short circuit. However, at home, it is unlikely that anyone will find it, so you can get out of the situation with a multimeter. About how, in the wiring, using the tester, we talked about in the corresponding article. If this does not help, we recommend calling the wizard, who, using a thermal imager or other devices, will find a short circuit and eliminate it.

AB out of order

Well, the rarest reason, which is also not excluded, is the poor quality of the machine, which knocks out due to the fact that it is defective. If you are sure that the wiring and household appliances are intact, and there is no overload, check the machine by replacing it with a similar one. We can say with confidence that this will help fix the problem. In order to avoid such a case in the future, we recommend that you familiarize yourself with and select one from the list.

What else can be?

In addition to the above reasons why the machine knocks out in the shield, there are also others that rarely occur. Let's briefly consider them too.

If the circuit breaker trips when the light bulb burns out, don't worry, this happens sometimes. The fact is that when the lamp burns out, a short-term overload occurs and if the nominal value of the machine is 6-10A, it is quite possible that it will knock out. This will not happen with LED and fluorescent lamps.

Sometimes on the forums you can find a situation where AV knocks out when the stabilizer is turned on. There are also some nuances associated with the operation of the device and your carelessness. The fact is that during start-up, voltage stabilizers create a current that can exceed the rating of your machine, as a result of which it will knock out. There may also be a reason in the stabilizer itself. Cheap Chinese models are famous for their marriage.

If the operation occurs when the light is turned on, check the lamps with a multimeter. We also talked about that.

The banal reason why the machine turns off is the incorrect connection of this device. If the conductors are not properly pulled to the terminals, heating occurs in this place, as a result of which the thermal release may operate. A visual inspection will help determine the cause - a melted body and wire insulation. If the plastic is very melted, it is better to replace the circuit breaker. In case of minor damage, it is allowed to simply tighten the wires harder with a screwdriver.

Let's deviate a little from the topic, but still note the important thing. If you have introductory and group machines in your electrical panel, it will be easier to find the cause. Knocks out AB on the input, without group ones? Check for correctness. If a certain machine is turned off below the main one, it means that there is a malfunction in this group (lighting, sockets or a separately connected hob).

It happens that the problem occurs after the flooding of the apartment. Water gets on the wire connections and if they are twisted with electrical tape, it sticks out, as a result of which the contacts close. After the flood, it is imperative to revise the wiring so as not to reach the situation when the circuit breaker starts to operate.

So we have provided all the reasons why the machine knocks out in the shield. Please note that this situation can occur both in an apartment and in the private sector. You need to act in the same way, even if the circuit breaker on the pole is turned off! If you are not confident in your abilities, it is better to call the master who will safely find the problem and fix it!

Interesting

Surely most of our readers are familiar with the situation when electricity is cut off at home, while the neighbors' legs are all right with this. First of all, you need to check the circuit breakers installed in the switchboard. Most often, it is their shutdown that causes the blackout of the home network. In this article we will talk about why a machine gun knocks out in an apartment or house. The reasons for this phenomenon can be different, and it is important to know them in order to prevent unpleasant consequences associated with the failure of electrical appliances or a fire in the wiring.

Features of the circuit breaker

To understand the reasons for the operation of the circuit breaker, you must first answer the question of what this device is for and what functions it performs. Features of the work of AV are as follows:

• The main task of the device is to protect electrical wiring and household appliances connected to it from too powerful a current that occurs for various reasons.
• The device is mounted on a phase circuit, the rupture of which occurs when the bag is turned off. If the machine has two or more poles, then when it is triggered, the zero circuit will also open.

• AB can de-energize the network both when it is turned off manually, and in the event of an emergency, which can lead to damage to the circuit elements.

Knocks out the machine: what are the reasons?

Now we go directly to the question of why the machine knocks out in the shield. The operation of the machine may occur for the following reasons:

• Power overload.
• Failure of one of the devices included in the circuit.
• Light fixture failure.
• Safety device failure.

Any of these reasons can lead to the fact that AB will knock out. Let's consider each of them in more detail.

Overload

This is the name of the situation when the magnitude of the current in the circuit exceeds the nominal value for which the protective switch is designed. For a better understanding, let's take an example.

To work with socket groups, AB are mainly used, the rated current of which is 16 - 25 A. This indicator corresponds to a total power of 3.5 - 5.5 kW. Let's assume that an electric stove with a power of 3 kW, a 1.3 kW electric kettle, and a 2 kW microwave oven are connected to the socket group, for the protection of which a circuit breaker is installed, rated for 25 A.

If we add up the power of the listed household appliances, then we get a load value of 6.3 kW. Considering that the maximum load that the protective device can withstand is 5.5 kW, the simultaneous activation of all three devices will cause the machine to knock out.

To avoid this, one should not take lightly the calculation of the total load in the circuit. If connecting the device to an outlet group would result in excess of the total power, it should be connected to a different circuit.

An example of incorrect wiring calculation on video:

Do not try to solve the problem by installing a machine designed for higher power. If its value exceeds that which the electrical wiring can withstand in its cross section, problems are inevitable. In this case, the cable, under the influence of too much current, will heat up until the insulating layer melts and causes a short circuit, and in the worst case, a fire. In this case, the machine will continue to supply current to the circuit until a short circuit occurs. Therefore, if a cable with a cross section of 2.5 mm² is used when laying the line, the AB rating for its protection should not exceed 16 A (for an aluminum conductor) or 25 A (for a copper conductor).

Breakdown of a household appliance

If you plug in a faulty household electrical appliance, then the likelihood that the machine will “cut down” is also quite high. How to find the device that caused the problem, consider an example.

Let's say the electric stove, microwave and oven are included in the network in the kitchen. In this chain, the machine was knocked out. To determine the cause of the problem, proceed as follows:

• Disconnect all units from the network.
• We turn on the machine. If it does not knock out without load, the wiring and protective device are working.
• We connect in turn household equipment. If, for example, when you turn on the stove and microwave, the chain works, and when you turn on the oven, the machine knocks out - the oven is faulty, and it must either be changed or repaired

Video diagnostic example:

Some types of household appliances (for example, dishwashing machines or air conditioners) are connected to the network directly, and not through an electrical outlet. Such devices must be disconnected from the protective device installed inside the switchboard - this is the only way to check them.

Malfunction of lighting devices

Now let's figure out why the machine knocks out when you turn on any lighting device. In any case, the cause is a malfunction of the latter, which may be as follows:

• Short circuit in the base of the electric lamp. To find the faulty element, you need to unscrew them all and, screwing in one at a time, turn on the lighting device. When, after screwing in the next light bulb, when the light is turned on, the AB is triggered, this means that the cause of the problem has been found. A light bulb with a broken base must be replaced with a serviceable one. Of course, if the only bulb in the device burned out and the machine knocked out, the cause of the malfunction is obvious, and there is no need to waste time looking for it.

Please note that sometimes the bulbs burn out due to a faulty switch - this may also be accompanied by a protective device.

• Burning of the contact between the power cable and the internal wiring of the device. To eliminate the malfunction, it is enough to clean the contact, and then insulate it with high quality.
• A short circuit inside the transformer of the LED chandelier. If turning on such a device leads to a knocked-out machine gun, there is a high probability that this is the problem. To troubleshoot a non-working transformer, you will need to replace it with a serviceable one.

As you can see, the reason for turning off the AB when the lighting device fails is most often a short circuit. In this case, the wiring does not have time to heat up to a critical level, therefore, the operation is caused not by a thermal, but by an electromagnetic release.

Failure of the circuit breaker

The reason for a sudden blackout of the network can also be malfunctions in the machine itself, but this happens very rarely, especially when it comes to models from well-known manufacturers. But if there is a suspicion of a malfunction of the protective device, it should be checked by connecting a new one that is known to be working. You can also disconnect the circuit from this AB and connect it to an adjacent bag in the switchboard. If these machines work, the problem must be looked for elsewhere.

Even an outwardly serviceable machine gun can knock out. Video example:

The reason for the failure of the circuit breaker can also be its long-term operation, during which there is a natural wear of its components and deterioration of their technical parameters. This also applies to breakers. As a result, the device may work even if the conductor has heated up slightly. This AB needs to be replaced.

What causes a differential circuit breaker to knock out?

A differential type circuit breaker can de-energize the network for the same reasons as a conventional one (if the wiring is very hot or a short circuit has occurred). But since, in addition to the releases, it contains an RCD, it also reacts to the leakage current, so it is not so easy to find the cause of the difavtomat operation.

If such a device works for no apparent reason, a more thorough check should be carried out.

Inspect the circuit breaker, if necessary - tighten the contacts. Check the condition of the electrical wiring in the switchboard. If the phase conductor touches a grounded metal case, this may cause the differential machine to knock out, although it will not lead to a short circuit.

Assume that no faults were found in the shield. Therefore, current leakage occurs in the protected circuit. Its reasons may be as follows:

• Faulty electrical appliance. If it breaks through its body, the RCD of the difavtomat is triggered, the task of which is to prevent electric shock to people.
• Shorting between a protective ground wire and a zero phase, which is sometimes done by inexperienced electricians.

• Heavy thunderstorm. Powerful electrical discharges often cause the differential protection device to be knocked out. In this case, it is better not to turn on the AB until the thunderstorm subsides.
• Worn insulating layer of old electrical wiring. In this case, the leakage of electric current occurs through microcracks and causes the machine to operate. Because these damages are hard to see with the naked eye, and the faulty cable doesn't get hot, it can be difficult to spot the problem.
• A sunken "Test" button on the device or a damaged body part also leads to the operation of the device. In this case, the defective device must be replaced.
• Installation of the machine is not according to the scheme.

The differential machine must be checked from time to time by pressing the "Test" button with the load disconnected. A working device should turn off. If it continues to work, this indicates a violation of the protective function and the need to replace the device.

Why the RCD knocks out - clearly on the video:

Wiring fault

The reasons for turning off the AV can be:

• Worn insulating layer of the cable.
• Bad contact in the switch or electrical outlet.

If the problem is in the switch or socket, then to fix the problem, you need to open the element, clean the burnt place and connect the cable correctly. With worn insulation, especially when it comes to hidden wiring, it is not easy to find the problem.

In this case, a special device will help - a locator, with which you can detect damage to the cable, even if it is hidden in the wall.

Having determined the location of the malfunction, it must be opened and the malfunction repaired, after which the groove should be repaired again.

Conclusion

In this material, we figured out what reasons, in addition to an excessive heating of the cable, may cause the circuit breaker to trip. Now you know what to do when a light bulb burns out while turning off the protective device, as well as how to troubleshoot if the wiring inside an electrical element burns out or if a household appliance fails.

Electricity is good as long as it works properly. Any malfunction in the electrician baffles most people on the planet. In this article, we will look at how to determine the malfunction of the circuit breaker and how to fix it.

By the way, not everything always works as it should, not only in electrics. The repair of the equipment that helps us is the same workflow, so millet needs to be prepared for it. This also applies to road construction equipment. A reliable supplier of spare parts with a wide range of spare parts for most global manufacturers will help in the repair of road construction equipment. Where to find it? Try on the site arsenal-zapchast.ru. You will not regret it, there are spare parts for 13 brands of leading manufacturers of road construction equipment.

Circuit breaker and short circuit

I'll start over. Circuit breaker or designed for (cables and wires of electrical wiring) premises against short circuit and overload. A short circuit leads to the instantaneous occurrence of overcurrents in the electrical network (currents that are orders of magnitude higher than the operating currents).

Any overcurrent, and in apartment circuits it is 1.8-12.6 kA, according to the laws of physics, leads to the release of colossal thermal energy. More than one household contact cannot withstand this energy, and a flash or a so-called electric arc occurs at the place of a short circuit. If you do not quickly turn off the power supply of the emergency network, then the probability of a fire is very high, and even worse, a person is injured by short circuit overcurrents.

To protect against short circuits, namely for the instant shutdown of the emergency network, automatic switches (protective circuit breakers) are used. I note that the shutdown does not occur instantly, but during the time of safe contact. It's less than 0.1 sec.

Circuit breaker and overload

The second purpose of the circuit breaker is overload protection. In there is a bimetallic plate (thermal release), overheating of which disconnects the electrical circuit from power. Overheating of the plate occurs when the network is overloaded. It is clear that the heating and, accordingly, the disconnection of the circuit does not occur instantly, but after a while. Depending on the heating of the circuit breaker, this time may be less than a second or several tens of seconds.

We turn to the malfunctions of the electricians of the apartment.

Malfunction of the circuit breaker in the mains

Your circuit breaker is periodically knocked out. The probable reasons for this are as follows:

• Short circuit in the circuit;
• Network overload;
• Damage to wires intermittently resulting in either a short circuit or overload.

First you need to diagnose the electrical network for overload and short circuit. If these faults are not found, and the machine still turns off, then the circuit breaker itself is very likely to malfunction.

Checking the circuit breaker

Do a basic circuit breaker check.

• Turn off the power supply ;
• Turn off all circuit breakers;
• Flick the cocking lever of the circuit breaker. It should turn on and off with a characteristic “click” sound.
• If a click is not heard, the machine is faulty and needs to be replaced.
• If there is a click, use a measuring device to measure the resistance between the terminals of the circuit breaker. When "on" machine resistance should be close to zero. When "off" machine resistance should be close to infinity.

However, even if the diagnostics of the machine showed that the machine is working, this does not mean that the setting (thermal release) of the circuit breaker is working.

Generally speaking, factory failure of circuit breakers is not uncommon and significant. What can we say about the emerging malfunctions of machines in the process.

For example, the machine worked a couple of times and failed. Or "survived" too much overcurrent and failed.

It is impossible to exclude the malfunction of the circuit breaker itself, as the main reason for its periodic shutdown.

Advice, change the automatic protection to a new one, do it again first.

The matter is simple, and such a replacement can save you from capital work to find other electrical faults in the apartment.

Then any person more or less familiar with electrical engineering goes to the site to check in the electrical panel state of circuit breakers. Most often, troubleshooting comes down to restarting the machine.

The fact of operation of a modern modular automatic switch is easily determined: the handle is in the “down” position, a round sign is clearly visible on it - “zero”. To turn it on, just turn this knob up, then a horizontal line will appear, and it will be possible to consider that the mission is completed.

Many apartments in the post-Soviet space are equipped with shields with machine guns of a slightly different type. Automatic switches of the AE series and the like have slightly larger dimensions, are attached to the base with long screws and have an unpleasant property: when triggered, their handle remains in the same, up position. This makes it difficult to find a triggered machine that must be turned off and on again in order to reapply voltage.

But all this, by and large, trifles. A triggered machine indicates some kind of malfunction, and we need to figure out which one.

Circuit breaker releases

To begin with, we need to find out, at least in general terms, what is a circuit breaker and how does it work. Many people know that the machine breaks the "phase". A multi-pole machine can also break the zero working conductor. But the machine can break the chain not only at the request of the owner, turning the handle down. That's why it's an "automatic" switch, that it can turn off automatically.

This is necessary in order to protect conductors and residential electrical equipment from increased electric current, which can cause fire and destruction. The reason for the increase in current can be:

1. Network congestion. It can be caused by the inclusion of faulty electrical receivers, or electrical receivers, the total power of which exceeds the capabilities of the network. The latter can also be associated with the apartment, when one group has a large number of sockets. Each socket individually may well not be overloaded, but their total current can reach values ​​\u200b\u200bthat are unacceptable for one machine.

For protection against overload currents in circuit breakers, thermal release- a bimetallic contact, the state of which depends on the temperature, which, in turn, depends on the flowing electric current. The setting, that is, the operating current of the thermal release, can usually be adjusted within small limits.

2. Short circuit in the network. It can be caused by a faulty electrical wiring or failure of any electrical receiver. For new wiring, a short circuit may be the result of an installation error, for example, when connecting wires in. Physically short circuit- this is the electrical connection of the phase and neutral conductors in addition to the load. Since the resistance of the circuit in this case is limited only by the resistance of the wires, the electric current instantly reaches a very large value.

To protect against overcurrent short circuits, the thermal release of the machine is ineffective: while the bimetallic contact heats up and breaks, the wires will almost certainly be damaged, and the electric arc will cause a fire. Therefore, in modular circuit breakers, it is always used electromagnetic release, the response speed of which is a fraction of a second from the moment the current increases.

So, if the circuit breaker in your apartment panel has tripped, then you can, of course, turn it on again. However, systematic operation indicates some kind of problem that will have to be solved. What to do if the machine in the electrical panel is turned off?

Short circuit in the socket circuit

With the instantaneous operation of the machine after it is turned on, there is every reason to believe that we are dealing with a short circuit - the thermal release will not work so quickly. You can verify the presence of a short circuit using - the resistance between the zero working bus N and the output of the circuit breaker during a short circuit should be close to zero. Of course, such measurements can be carried out only when the machine is turned off.

As soon as we are convinced that the reason for the operation is a short circuit, then it is necessary to find out exactly where it happened. The circuit breakers in the shield must be selected in accordance with the principles of selectivity, which means that it is the circuit breaker located closest to the short circuit that should work. In this case, the switch reacts only to short circuits in that part of the circuit that is located after it relative to the line.

Therefore, let's say, if only the introductory circuit breaker is triggered, then the place of the circuit is most likely located directly in the introductory shield. When closing within the apartment, a group switch is activated and often with it an introductory machine. In this case, the introductory device can be safely turned on again and find out which particular group of electrical receivers is connected to the problem wire - this group will not work.

Having clarified this issue, you can turn off all these electrical receivers and re-enter the group machine into operation. If it does not work, then the reason is a malfunction of one of the disconnected electrical appliances. You can find a specific culprit either by turning on all the electrical receivers in turn, or by measuring their input resistance. The second method is not suitable for devices with electronic control. A defective device, of course, is subject to repair.

If all devices are in good order, it is necessary to start inspecting the sockets that are part of the group: disassemble the plastic cases, check and tighten the terminal clamps. After the sockets comes the turn of the boxes. They will have to be opened. And if the inspection does not reveal obvious faults, then the wires must be disconnected in order to check the resistance between the cable cores separately. Such a check will already accurately determine which of the cables has a short circuit. The damaged line must be replaced and the cores in the box must be reconnected using certified clamps.

Short circuit in lighting circuit

If a tripped circuit breaker protects the lighting circuits, then the test can be started by inserting the circuit breaker with the circuit breakers turned off. The machine did not work - you can alternately click the switches in order to find out in which circuit of which there is a short circuit. Thus, we narrow the search area to a chain of a group of lamps input from one switch.

In this group, each lamp should be carefully examined by unscrewing the lamps and examining the terminal clamps. With a multimeter, you can measure the resistance between the phase and neutral wires from the side of each lamp. In this case, it is possible to determine the luminaire or cable line in which the short circuit has occurred.

If a short circuit is detected on all luminaires of the group, or is present in the network, regardless of the position of the switch, then the place of the circuit is most likely the lighting junction box. It must be opened and checked in the same way as in the case of closing the outlet network. Well, if the box is in perfect order, then we call individual cable lines by disconnecting their ends.

Network congestion

As already mentioned, in the event of an overload of the network by current, the circuit breaker takes some time to trip. It usually takes a few minutes. Therefore, if the machine kicks out from time to time, then it may very well be that you are dealing with an overload.

Light circuit overload- the phenomenon is quite rare, and in order to avoid it, use only lamps that are suitable in terms of power for your lamps, and upgrade the lighting circuit taking into account the power reserve. After all, the lighting circuits of individual apartments are often protected by one machine for ten amperes. This is often enough, but when installing a large number of additional lamps in the panel, it is necessary to provide an additional lighting machine to power them, especially if the lamps are halogen or with conventional incandescent lamps.

Outlet network overload- it's not uncommon at all. During the design and installation of electrical wiring in the house, it is impossible to accurately determine the load on each group. Therefore, for the convenience of residents, there are three to four sockets per group, switched on by one circuit breaker. And, despite the fact that the rating of the circuit breaker is usually selected according to the cross section of the supply wire and does not exceed 25 amperes, the rated current of the sockets can be 16 amperes.

There are all the prerequisites for overloading, if all powerful electrical receivers, such as a kettle, iron, microwave oven, and the like, are plugged into sockets of the same group. Here, of course, the automatic switch will work. And in order to prevent this from happening, it is necessary to evenly distribute a powerful load between groups, and in the absence of such an opportunity, do not include several powerful electrical receivers in the network at the same time.

It happens that a faulty electrical appliance consumes increased current, which leads to network overload and tripping of the circuit breaker. It is not always possible to measure the current in domestic conditions, but if the thermal release occurs only when one electrical receiver is turned on, and the rated power of this device does not exceed 2.5 kW, then it should be audited for faults.

Circuit breaker failure

It is not uncommon for the cause of the constant tripping of circuit breakers to be a malfunction of the latter. Even among new machines, a certain number of defective copies are allowed. Their inability to keep the setting (and this applies mainly to thermal releases) is often detected only during operation.

Therefore, with the systematic operation of the thermal release of the machine, before embarking on radical methods for solving the problem, you can simply make a trial replacement of the machine with one similar in rating and characteristic.

Finally

In the article, we deliberately bypassed the moments when the machine is triggered - this is a topic for a separate discussion. For the same reason, we did not touch on the situation when the differential circuit breaker trips.

But in the end, I would like to remind you that the most popular way to solve the problem of a triggered machine - replacing it with a machine with a higher denomination - is categorically unacceptable. Circuit breakers are devices that provide protection against fire and damage. Their denomination is selected precisely for the purpose of ensuring security. An arbitrarily chosen machine will not perform its functions and will not protect against dangerous operating modes of the electrical network.

Alexander Molokov