How to connect the machine in the dashboard: choose and connect the machine correctly, recommendations. Connection of the circuit breaker in the panel Functionality of the circuit breaker
If you ask any person inexperienced in electrical engineering what is in an electrical panel, then an immediate answer will follow - automata. Although there may be, in addition to circuit breakers (this is the correct name for the machines), there may be differential circuit breakers, load switches, contactors, impulse relays and much more. The purpose of this article is to find out how to single out the circuit breakers from the whole variety of modular devices, what they are intended for, how to choose them correctly, how to connect the machine in the panel and what to do when triggered.
Why does an ordinary consumer need knowledge about circuit breakers
At first glance, it may seem that an ordinary person who is completely unfamiliar with engineering in general and electrical engineering in particular does not need to know anything about circuit breakers, because the wiring in an apartment or house was done by professionals. It is possible that this is so, but what will a person do if the tension suddenly disappears in the whole apartment or house or in some part of them. Of course, the person will open the flap, see what kind of "knocked out", and again move the lever to the "on" position.
It is in this action that the main mistake of "ordinary people" lies, because before turning on a triggered modular device, one must understand the reason for its operation. Therefore, do not be surprised when, after switching on again immediately or after a while, switching off again follows. Without eliminating the cause, you should never re-enable modular devices, including circuit breakers (hereinafter machines). This can lead to sad consequences both for the health and life of a person and for property.
The fact is that different protection devices have their own functions, therefore, the reasons for the operation of machines and (RCD) are completely different. And in most cases, this does not apply to the quality of electrical wiring. Of course, an experienced electrician will always find a reason. But if incidents with electricity occur at night or on a weekend, then not every electrician will agree to promptly solve the problem that has arisen, and if he does, then the owners will have to pay well from their pockets for the urgency.
As the electricians themselves say, 50% of cases of triggering of protection devices are banal and occur through the fault of the owners themselves and the wiring has nothing to do with it. That is why basic basic knowledge of protection devices, their purpose and the rules of response when they are triggered will be very useful. The authors of the article will try to explain everything in understandable language, without going into the jungle of technical nuances that will be of interest only to specialists, but not to “ordinary people”.
What is a circuit breaker and what is it for?
A circuit breaker (machine) is a device that is designed to switch (in other words, turn on and off) an electrical circuit. That is, it means that you can manually turn on and off the electrical circuit using the lever.
However, the name itself - a circuit breaker, says that the machine should automatically turn off the load. When does this happen?
- When the circuit protected by the circuit breaker flows a current that exceeds the permissible one. And the greater the excess current, the faster the shutdown occurs.
- When very large currents appear in the protected circuit, which are unusual for the load - the so-called short-circuit currents. In these cases, the machine reacts very quickly - within a fraction of a second.
An overload can occur when one powerful load is simultaneously turned on in one circuit protected by the machine, for which neither the circuit breaker nor several powerful loads are designed. For example, in one outlet circuit of six outlets, an electric kettle, iron, electric fireplace, microwave oven, double boiler and hairdryer are turned on at the same time. Naturally, with such a load, the current will exceed its nominal values by much, the wires will be very hot from this, which can lead to melting of the insulation and, in the future, to a short circuit. The machine must not allow this and must disconnect the circuit even before the wires become very hot.
Short-circuit currents can occur when an insulation breakdown to the case occurs in any device or the phase and neutral conductors are closed. According to Ohm's Law, the lower the resistance, the greater the current. The higher the current, the more heat is generated, which leads to melting and ignition of the insulation. Short circuits are the most common cause of electrical wiring fires. That is why a very important function is assigned to the machine - to instantly react to short-circuit currents, that is, to those currents that are many times higher than the rated ones. The reaction time of the machine must be such that the wires do not have time to heat up to dangerous temperatures.
From all of the above, one important conclusion follows: the circuit breaker is designed to protect wires, cables and various electrical devices included in the circuit from overload and short circuit. There is not a word about a person. Therefore, the main thing should be understood - the machine does not save a person from electric shock. The machine saves cables and wires.
Let's give an example. Suppose the lighting circuit in the apartment is protected by a 10 Ampere automatic machine and a person, changing a light bulb in a lamp, accidentally touches a live phase conductor, and touches the grounded refrigerator case with the other part of his body. An electric current begins to flow through the human body, which depends on the resistance - the more it is, the less the current. In the calculations, the resistance of the human body is taken to be 1 kΩ, which means the current will be I =U /R = 220/1000 = 0.22A = 220mA... For a lethal shock to a person, 80–100 mA is enough, and the machine has a rated current thousands of times higher. Therefore, we repeat - the machine does not save a person from the damaging factors of electric current. Of course, a triggered machine can save someone's life if it prevents the electrical wiring from igniting, but it does not save a person from direct exposure to electric current.
Briefly about the "inner world" of the machine
A circuit breaker is a complex electromechanical device. Some modern models of machines are equipped with electronic units that more accurately track the flowing currents, but in this article we will consider the device of the "classics". The sectional machine is shown in the following figure.
The terminals are located in the upper and lower parts of the machine, and it is always assumed that the entrance is at the top and the exit is at the bottom. The upper terminal is rigidly connected to a fixed contact, and the lower one is connected to a thermal release, which is a bimetallic plate that bends when heated. The end of the bimetallic plate is connected with a flexible conductor to one of the terminals of the solenoid of the electromagnetic release. The other output of the solenoid is connected with a movable contact by a flexible conductor.
The release mechanism is designed in such a way that the movable contact is spring-loaded and reliably fixed both in the on and off state. In addition, the springs allow switching very quickly, which avoids strong burning of the contacts during a spark or arc discharge, which can occur precisely at the moments of shutdown.
The release mechanism can be operated in three ways:
- Turning on the machine, that is, when the movable contact is pressed against the fixed one, is possible only manually, through the control lever of the release mechanism. You can also manually turn off the machine.
- In case of overloads in the circuit, the current, which exceeds the rated one, passes through the bimetallic plate of the thermal release, and heats it up. Under the influence of temperature, the plate bends and presses the lever of the release mechanism, which turns off the machine. The higher the current overload, the faster the plate heats up and the faster the mechanism is triggered.
- If short-circuit currents appear in the circuit, then the current passing through the solenoid of the electromagnetic release induces a magnetic flux capable of drawing in the spring-loaded solenoid core, which, in turn, acts on the movable contact and opens the circuit. In this case, the reaction time for good machines can be thousandths of a second.
At the moment of disconnection, a spark discharge may occur between the moving contact, which ionizes the atoms of the gases that make up the air. Ionized gas is a good conductor, so an electric arc can break out, in which the temperature can reach several thousand degrees. Naturally, such a thermal effect will very quickly burn out the circuit breaker, unless special measures are taken.
The machines always have a special arc chute, which is a set of copper or copper-plated steel plates that are insulated from each other. When the arc ignites, it forms a powerful magnetic field, which induces an EMF in the plates, which also forms its own magnetic field of opposite polarity. These fields interact with each other, the arc is drawn into the plates of the arc chute. The plates "chop" the arc into pieces and cool it, as a result of which it quickly extinguishes. When the arc burns, a large amount of gases is formed, which freely leave the machine body through a special hole located below the arc chute. This process can take a fraction of a second, but even this time is enough for a spark discharge or arc to "scorch" the contacts a little.
Over time, with frequent switching on and off of the machines, the contacts burn out. There were times when the contact pads of circuit breakers were made of electrical silver, there are such devices now, but they are not used in household wiring. Therefore, it is not necessary to "click" the lever of the machine without a special need, since at each action there at least a spark discharge jumps over, causing the erosion of the contacts. The machines are designed mainly to protect the cable or wire, and there are special devices for switching - load switches, called in Russian knife switches.
Find out its purpose, basic schemes, common mistakes, in a special article on our portal.
How to choose the right circuit breaker
Before installing a circuit breaker in an electrical panel, it must be correctly selected so that it matches both the cable and the nature of the load. Therefore, we will consider the main characteristics of modular machines, which are always indicated on their labeling. For a specialist, marking says a lot, but for an “ordinary person” it does not mean anything. Therefore, you need to learn how to read it, especially since there is nothing complicated about it.
Educational program on labeling machines, selection of the required model
The figure shows typical markings for all circuit breakers. Let's consider all the points one by one and comment on which machines are needed for various purposes.
Trademark
The trade mark is always indicated in the upper part of the faceplate of the machine, which in other words means the manufacturer. For protection devices, this is of great importance, since it is better to choose an automatic machine from a well-known brand. These are: ABB, Legrand, Hager, Merlin Gerin, Schneider Electric, IEK, EKF. In the matter of choosing a specific model and series, it is better to consult with a good (not ZhEKovskiy) electrician.
Rated voltage and frequency
If the machine has an inscription 220 / 400V 50 Hz, it means that this device can operate both in single-phase and three-phase AC circuits with a frequency of 50 Hz. Most of the machines used in household wiring have this opportunity.
Rated current
This is one of the main characteristics that indicates what maximum current in amperes can flow through the machine for a long time without triggering it. It is designated I n... If the current becomes more than the nominal by 13%, i.e. I =I n * 1.13, then the thermal release starts to work, but its response time will be more than an hour. Upon reaching I = 1.45 *I n the tripping time of the thermal release will already be less than an hour and the higher the current, the shorter the tripping time.
The rated current of the machine must always correspond to the cross-section of the cable or wire of the circuit it protects, but not the load power. The machine should not allow them to overheat when an electric current flows, but in real life the opposite often happens.
For example, a family has acquired a washing machine and when it is connected to an existing outlet, after a while in the driveway, the machine knocks out the machine, since the total load turns out to be higher than it can tolerate. An electrician who came from the housing office offers an “ingenious” solution to change the machine to another one with a higher rated current. For example, in the dashboard there was an automatic machine for 10 A and it is proposed to change it to 16 A, or even to 25 A, so that it was "more reliable". The machine changes and, to the delight of the owners, it really stopped knocking it out when the washing machine was running. And it is made with an aluminum wire with a cross section of 1.5 mm 2, which is far from uncommon in houses built in the era of the USSR.
Naturally, at peak loads, the wire will overheat, its insulation will melt, but the machine will not react in any way, since its response threshold is much higher. Unfortunately, such situations are far from uncommon. And the owners will be very lucky if there is no fire, but a short circuit occurs, which will cause the machine to work.
You should understand the simple rules that will help you choose the right machine that is guaranteed to protect the wiring from overheating.
- or the wires must match the load.
- The circuit breaker rating should only correspond to the cross-section of the cable or wire, but not to the load.
The table below shows the correspondence of the cross-section of the copper cable or wire and the rated currents of the circuit breakers. In any case, it is necessary to be guided by just such a correspondence and nothing else. No exceptions and no arguments like "I've done this a hundred times."
electrical shield
It can be seen from the table that the machine does not allow using all the possibilities of a cable or wire for passing an electric current, but limits them. And this is done intentionally, the circuit breaker is a kind of "weak link" that will not allow the cable or wire to "strain" too much, which, from a safety point of view, is very useful.
Rated current circuit breakers are available in 1A, 2A, 3A, 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A.
Time-current characteristic
Before the value of the rated current in the marking of the machine there is an alphabetic index that reflects the time-current characteristic (VTX). It is not known for what reason, but, from the point of view of the authors, not enough attention is paid to this. Let's figure out what this characteristic is.
The figure shows a graph of the dependence of the response time of the machine on the multiplicity of the flowing current to the nominal, that is k =I /I n... The graph is divided into three colored zones: green, blue and yellow, which corresponds to the time current characteristics of B, C and D. The following conclusions can be drawn from the graph:
- If k is greater than 3, but less than 5, the automaton belongs to category B.
- If k is greater than 5, but less than 10, the automaton belongs to category C.
- When k is greater than 10, but less than 20, the automaton belongs to category D.
What does this mean in human language? It can be seen from the graph that in any categories of machines, the greater the multiplicity of the flowing current in relation to the nominal, the faster the operation will occur. Circuit breakers with BTX category B react the fastest of all to overcurrents, followed by automatic circuit breakers of category C, and then D. There are also automatic circuit breakers with characteristics K and Z, but they are not used in apartment buildings.
It should be noted that the graph is given for certain external conditions, namely an ambient temperature of + 30 ° C. When the temperature rises, the automata will operate at slightly lower currents, and when the temperature is lowered, on the contrary, at higher currents. This difference is not so significant, but it still exists. A very great influence on the operation of circuit breakers is exerted by their "neighbors" on the electrical panel, which, heating up when an electric current flows through them, heats up the air inside the panel and the equipment nearby. That is why experienced electricians try to choose such models of electrical panels that have a lot of free space inside and, when assembling them, do not try to clog them with modular equipment "to capacity".
The question is, why divide the circuit breakers into VTX categories. After all, you can simply make such an apparatus that will simply react by switching off to an excess of the flowing current over the nominal one. But not everything is so simple. Some types of electrical loads, when switched on, consume currents that are much higher than during operation. For example, the electric motors of a vacuum cleaner or refrigerator compressor may consume 3-8 times the nominal current at the time of start-up. If the machines react to such an excess every time, then life will turn into a living hell - every time the refrigerator is turned on, the machine in the dashboard vibrates. That is why thermal releases are used in the machines, which have a certain inertia, which allows a short-term excess of current to be allowed, which does not lead to overheating of the wires. In any case, the thermal release is configured in such a way that it disconnects the circuit before the cables and wires enter a dangerous mode for them.
In the wiring of apartments and private houses, circuit breakers from categories B and C are used. When choosing a specific model, the nature of the load should be taken into account. For active loads, that is, those that do not consume increased currents at start-up, you should choose automatic machines with BTX type B. This applies to lighting and socket circuits. Reactive loads will already require type C VTX machines. These include refrigerators, air conditioners, washing machines and dishwashers, and home workshops where power tools are used.
Unfortunately, it is very difficult to find type B circuit breakers in electrical supply stores. This is due to the low demand for them. The lion's share of the machines sold is type C VTX. But the authors of the article strongly recommend not to spare money and use type B machines for active loads. Even if you have to order them and wait a while. The fact is that by combining circuit breakers with characteristics B and C, it is possible to achieve selectivity in the operation of protection devices.
Let's give an example. Let's say an incandescent lamp burned out in one of the lamps, but at the same time the spiral closed. Surely everyone has come across such a situation when, when the light is turned on, the lamp flashes and immediately goes out with a characteristic click and at the same time knocks out the machine. It is good if the machine has worked, which protects only the lighting circuit of the room, but it can happen that it knocks out the machine located in the driveway. Moreover, it happens that the automatic machines in the apartment dashboard did not react, but the driveway did. If this happens, it means that selectivity is poorly organized in the organization of the wiring.
The main principle of selectivity is that the protection devices closest to the source of the problem must be triggered first. If for some reason they did not work, then other devices higher in the hierarchy should respond. In the described case, with a lamp, you can put an automatic machine with BTX type B on the lighting circuit, and install a category C automatic machine in the driveway. Then, when the lamp coil closes, first of all, a more "nimble" type B machine will work, while the approach machine "dulls". In this case, its slower reaction is beneficial, since it will not lead to the shutdown of the entire apartment.
Rated breaking capacity
This characteristic can also be called the limiting switching capacity (PSC). The PKS shows at what maximum short-circuit current the machine will still be able to open the circuit at least one (and this will most likely be the last) time. The standard values of the PKS are 4.5 kA, 6 kA, 10 kA. For domestic use, 4.5 kA is quite enough, but if the substation is located nearby, then it makes sense to use automatic machines with 6kA PKS. Circuit breakers with PKS 10 kA are used only in industry.
Current limiting class
This characteristic has three values - 1,2 and 3, and if there is no this marking, then the machine belongs to the 1st class. It shows how quickly the machine will react to the appearance of short-circuit currents. If the thermal release when an overload occurs can "wait tactfully", then the electromagnetic release should act "decisively and boldly" when the TKZ appears. The class of current limiting precisely reflects the degree of "decisiveness" of the machine and the time of its reaction.
Class 1 opens the circuit in one half-cycle, which is approximately 10 ms in time, class 2 - in ½ half-cycle (5-6 ms), and class 3 in 1/3 half-cycle (3 ms). Naturally, the higher the class, the better, but also more expensive.
Number of poles
In modern apartment or house switchboards, modular circuit breakers with 1, 2, 3 or 4 poles are used. Single-pole and double-pole circuit breakers are designed to protect single-phase circuits, and three and four-pole - for three-phase. According to the number of poles, the circuit breakers occupy the number of places (modules) in the electrical panel. One place is 17.5 mm.
Video: How to choose circuit breakers
As noted above, modern circuit breakers used in household wiring are modular equipment, which, along with other control, switching, metering and protection devices, have housings of standard sizes in length and height, and the width is always a multiple of one module (place) equal to 17 , 5 mm.
All modular equipment in electrical panels is mounted on a 35 mm DIN rail with a latch. To install, simply snap the machine on the rail, and then, moving it to the left or right, set it to the desired position. And to remove it, you already need a flat-blade screwdriver, which you need to pry off and pull up the spring latch.
To install and connect the circuit breaker to the electrical panel, you will need a standard set of electrical tools:
- A set of screwdrivers, both straight and Phillips. You should pay attention to which screws, with which slot, are used in the terminals of the machine. There are two options: a Philips cruciform (in the figure numbered 2) or a Pozidriv cruciform (in the figure numbered 3). They are designated PH or PZ, respectively.
Each slot has its own tool: a screwdriver or a bit - Pliers in various sizes.
- Nippers or cable cutters.
- Stripping tool - stripper.
- If stranded wires are used to connect, then you will need a tool for crimping the terminals - a crimper.
- Indicator screwdriver.
Let's describe the process of installing and connecting a circuit breaker in the electrical panel.
| Image | Description of the process steps |
|---|---|
 | The electrical panel is completely de-energized, measures are taken to prevent unauthorized switching on of voltage. with an indicator screwdriver, the absence of voltage in the shield is checked. |
 | The automatic machine of the selected rating snaps into place on the DIN rail. |
 | If there are empty gaps to the left and right of the machine, then it is advisable to use special stoppers that prevent the equipment from moving left and right along the DIN rail. |
 | When connecting a single-pole circuit breaker, a phase from the input device or an RCD (individual or group) must be supplied to the upper terminal, and the phase of the protected circuit must go from the lower terminal. |
 | When connecting a two-pole circuit breaker, a phase should be applied to the upper left terminal, and zero to the right. The phase of the protected circuit should "leave" from the lower left, and zero from the right. |
 | When connecting a three-pole circuit breaker, the phases must be supplied to the upper terminals in the order they follow from left to right A, B, C (L1, L2, L3). The phases of the protected circuit must respectively "leave" from the lower terminals in the same order. |
 | A four-pole machine is connected in the same way as a three-pole one, only a zero wire is added - the far right. |
 | In the electrical panel, suitable wires and wires of the protected electrical circuits are laid to the corresponding terminals of the circuit breakers. The incoming ones are routed to the upper terminals, and the outgoing ones to the lower ones. The only way! When laying, use existing wire bundles. If necessary, the wires to be laid are tied to the bundles with plastic clamps. |
 | When laying wires, avoid sharp turns, which can provoke kinks. Also, do not pull the wire taut. |
 | When the wires are laid to the terminals of the machines corresponding to them, the required length is measured so that the wire freely enters the terminal. Excess ends are bitten off. |
 | A stripper removes the insulation from the ends of the wires by 10 mm. In the absence of a stripper, this can be done with a construction knife, but at the same time it is necessary to try not to make cuts of the insulation perpendicular to the wire - this can provoke further wire bending. |
 | If stranded wires are used, then they must be terminated with NSHVI-type tips, which are crimped with a special tool - a crimper. |
 | If the circuit breaker is located next to the others in the electrical panel and one phase or phase is “heard” on all of them together with zero, then it is advisable to use special busbars-combs, which, like automatic machines, are one, two and three-pole. |
 | In the absence of combs, jumpers can be prepared from the PV3 assembly wire and NSHVI lugs (2), intended for crimping two wires. It is not allowed to place two separate wires under the terminal of the machine. |
 | After checking the conformity of the installation to the schematic diagram of the electrical panel, the wires are placed in the previously released terminals of the machine and clamped with a screwdriver with a force of 0.8 N * m. Do not try to tighten "with all the foolishness", as this can lead to breakage of the machine case. |
 | Voltage is applied to the electrical panel, all protection devices are turned on, the presence of voltage at the input and output of the machine is checked with an indicator screwdriver or multimeter. |
 | The insides of the electrical panel are closed with a protective cover - a plastron. The circuit breaker is marked with its belonging to the protected circuit. Marking is also done on the plastron. |
Video: Circuit breakers - polarity and connection diagrams
What to do if the machine in the electrical panel is triggered?
If during the operation of the electrical wiring, a circuit breaker has tripped, then this can be for many reasons. Therefore, you should not rush to turn it back on right away, but try to find out the source of the problem. In this case, one should be guided by the following:
copper wire
- Any disconnection of the machine causes strong heating of its insides, especially the bimetallic plate of the thermal release and the solenoid. Before turning on the load, let it cool down for a few minutes.
- While the machine is cooling down, you need to walk around the apartment or house and inspect all the sockets, switches, lamps, powerful consumers of electricity. The smell of burning insulation, darkening from exposure to fire, hot plugs can tell a lot and indicate the source of the problem.
- If everything is in order with the selectivity in the electrical panel and only one automatic device that protects a specific circuit has worked, then the task is simplified, since it is necessary to inspect the consumers of only this circuit. It is much worse when the input automaton is triggered and others “ignored” the problem. Then you will have to turn off all the lines protected by the circuit breakers, turn on the automatic input and sequentially turn on all the circuits, one at a time. After turning on any circuit, it is necessary to give a certain delay time and at the same time inspect all electrical appliances that are connected to the machine.
- If, when the automatic machines are sequentially turned on, one of them triggers or turns off the input machine, then the source of the problem has already been localized and the problem must be looked for in a specific circuit. It can be some kind of faulty consumer of electrical energy, a burned out lamp with a closed filament, melted insulation in some section of the wiring, and much more. To find out what is the matter, when the machine is off, it is necessary to turn off all consumers of electricity in this circuit, and then turn on the machine. If it works, then the problem is in and without the help of specialists. If not, then all consumers must be connected in series, which will help identify a faulty device.
- Turning off the machine in a separate line or input can provoke a very heavy load. For example, a washing machine, dishwasher, air conditioner and electric oven are turned on at the same time. The automatic input device may not be designed for such a load, therefore it turns off the circuit. In this case, it is necessary to separate the operation of powerful electrical appliances in time.
- Hot summer weather combined with high loads can also trigger the protection devices.
- And the last reason is a malfunction of the circuit breaker itself. It is possible that before that, he repeatedly tripped from increased currents, briefly endured short-circuit currents, and repeatedly extinguished the arc. All these influences, unfortunately, do not affect the life expectancy of the machine for the better. With the plastron removed, you can inspect the insides of the shield. A faulty machine can be identified by a melted body, burnt terminals and other signs. Simply replacing the circuit breaker can fix the problem.
Video: Circuit breaker - why does it work in the heat?
Video: Circuit breaker knocks out
Conclusion
- The circuit breaker is designed to protect the cable or wire, not people.
- The rated current of the machine must strictly correspond to the section of the protected cable or wire.
- In circuits with a resistive load, it is better to use automatic machines with a time-current characteristic of category B, and with a reactive one with high inrush currents - category C.
- A competent combination of circuit breakers with BTX B and C will ensure selectivity.
- When a circuit breaker is triggered, the source of the problem must first be identified. If you can't do it yourself, then you should call a specialist.
Reliable and safe electrical wiring for you!
Sometimes even the simplest manipulations and connection of simple electrical devices such as a light switch or an automatic device can cause a lot of questions. In principle, nothing is difficult, you just need to clearly understand:
- the purpose of each element of the circuit;
- safe techniques for connecting the switch;
- nominal values of each apparatus;
- know the power supply system and the geography of the location of electrical devices.
The list of tools that will be needed in this case is also minimal:
- Indicator screwdriver or voltage indicator with phase indicator;
- A screwdriver with a strong handle made of good steel, which will ensure a secure clamping of the bolted contact connection;
- Pliers;
- Insulating material (electrical tape).
Of course, all these rules and techniques are applied to connect and install household circuit breakers, as well as lighting switches. In industrial premises and conditions, connecting an automatic power switch is a time-consuming work associated with large-sized electrical devices, and there will already be need for socket and spanner keys in order to reliably and efficiently mount the housing and the contact part. In everyday life, a phase voltage of 220 volts is most often used, which is a consequence of being connected to a three-phase circuit with a dead-grounded neutral. That is, in order to get this voltage equal to 220 Volts, you need to connect to the phase conductive cable and to the neutral wire. Between the two phases, the voltage will already be 380 volts. This voltage is used in everyday life, most often in their own houses and cottages, when you need to connect a three-phase motor (compressor, fan, pump) without power loss.
Connecting a double pole circuit breaker
Before connecting a circuit breaker, you need to understand the purpose of this device, its functions and capabilities. An automatic two-pole switch is, by and large, two single-pole circuit breakers assembled in a single case. According to the PUE, it is impossible to disconnect only one phase wire or zero, to ensure the safe operation of electrical installations. 
This device has several protections:
- From a short circuit, that is, from a sharp increase in large currents that arise in this case in the circuit;
- From a prolonged increase in current more than the nominal, by a given and clearly advertised value.
That is, the machine will turn off abnormally if, for example, it is designed for a working current of 20 A, and within 20 minutes, for example, 25 A will flow through it, a thermal relay will work in it, which can prevent it from being turned on again. Only after the circuit breaker, or rather, its thermal relay, cools down to operating temperature, will it be possible to re-enable. And also the machine turns off if a short circuit occurs in the outgoing circuit, that is, the one that went to the consumers.
How to connect correctly
To connect the switch, you first need to decide on the energy source, that is, where it will be powered from. The installation of circuit breakers in the panel will be carried out in any case, too, from a machine with only a higher rating.
But selectivity must be maintained. Selectivity is a well-tuned and selected mechanism for protecting devices in electrical circuits, as a result of which the circuit breaker is disconnected in this section of the circuit and it will be the closest to the place of short circuit or overload. In other words, if the power supply system of an apartment or room is divided into several parts, then in the event of a short circuit in the circuits in the kitchen, only the machine that feeds this kitchen will turn off, and not the input to the entire apartment.
A source is known to which you can connect the upper contacts of the machine, now you need to decide whether it will withstand all the loads and all consumers that will be connected. Each electrical device has its own ratings:
- Power consumption;
- Voltage;
- Current strength.
Each of them is important, but sometimes only power and voltage can be indicated on some devices. The approximate current strength can be determined by yourself; for this, the power of the electrical appliance must be divided by its operating voltage. The power switch should be selected in accordance with the sum of all devices that will be connected to it. For example, if there are three electrical devices that will consume 5 A each in the course of their operation, then the circuit breaker should be slightly with a margin of 20-25 A. Then the flowing operating current will be 15 Amperes, with the operating current of the machine 25. Everything the devices will work normally without overheating. And in emergency modes, they will immediately turn off the entire circuit, thereby ensuring reliable fire safety of the room. The polarity in AC voltage circuits does not matter, so there is no difference to which terminals the phase will be connected, and to which zero. In DC circuits, double-pole switches are also often used. One of the conclusions is negative, the other is positive, however, in domestic conditions, constant voltage is used very rarely.
Single pole circuit breaker connection
A single-pole switch is designed to switch lighting circuits, or even sockets. The main advantage of bipolar is lower cost. The main thing in creating and supplying circuits connected through such a device is that it must necessarily break the phase wire, the zero one can be connected directly to the junction box.
Installing a circuit breaker
The modern installation of the switch is based on its mounting on a DIN rail or strip. This is the simplest and most effective attachment mechanism. Groups of circuit breakers, or single ones, must be installed according to the rules of safe installation of electrical installations in special shields that prevent dust from entering the machines, as well as accidental contact of a person with its conductive parts.
It is imperative to remember that all work on installation, connection and installation must be done safely, which means with a complete disconnection and checking the absence of voltage. This activity can be performed with any voltage probe or indicator. It should be remembered that these works are related to the work of increased danger and can be the cause of human death.
The setting of the trip units of the circuit breakers is carried out by the manufacturer, therefore it is better not to adjust this system in a domestic environment.
Connecting the luminaire to the switch
Connecting a switch to a lighting fixture is a simple process, the main thing is to remember one basic rule that it is installed on a phase wire, and not on a zero. To do this, with the power supply turned on, you need to determine which wire is phase. For this, special devices are used:
- voltage indicators;
- pointing screwdrivers.
In order to connect the switch, it is imperative to remove the supply voltage from this section of the circuit.
But it is also necessary to ensure that there is no connection of copper and aluminum wires by the twisting method, but only through a terminal block or connector. The combination of these two materials over time leads to poor contact between them due to oxidation that results from the chemical reaction of these elements. The switch can be:
- One-key;
- Two-key;
- Three-key, etc.
In any case, the phase wire comes to them alone, and after that it diverges as a control for different lamps of the lamp. The twists in the junction boxes must be reliably and properly insulated so that a short circuit does not occur.
Lighting switches should be selected in accordance with the current, which depends on the power of the lamps. On all these elements and components of the electrical network, if you look closely, there are markings. For example, if you connect a light switch designed for 10 A, then the lamp current should be no more than this value, it can be less. Often the current is not written on the lamps, but only the power and voltage. The current will be equal to the power divided by the voltage. For example, if a 100 W lamp is connected to a 220 Volt network, then the current in its circuit will be approximately 0.45 A.
The correct choice, connection and installation of a circuit breaker and lighting switch is a guarantee of durable and trouble-free operation of electrical equipment. And also in emergencies, overloads and short circuits, the operation of the protection will protect the premises from fires.
Video about circuit breakers
Almost all modern circuit breakers used in residential buildings are DIN rail mounted. This is such a special "piece of iron" of a special shape, on which the machine is hung and snapped into place for fastening. If you have not seen all this yet, then do not be alarmed, everything will work out for you. In the photo below, I showed everything - where is the latch, and where is the DIN rail.
The machine is mounted like this! From above it is put on the rail, then the lower part of the machine is pressed against it, and we snap the latch from below. If you need to remove the machine, then first pull down the latch with a flat thin and preferably dielectric screwdriver, remove the lower part of the machine from the rail and remove it completely.
Specialists will now joke that, they say, I am describing such nonsense. I do this because I saw and more than once how adult men pulled out an automatic machine along with a DIN-rail or simply broke the latches, trying to remove it carefully, including my young partner. Well, before I had time to shout to him: "Stop! What are you doing?"
How to install a circuit breaker in a small plastic box? As a rule, it already has a DIN rail and there should not be any problems here. But if you decide to replace the circuit breaker in the old floor distribution board, where there are black dilapidated automatic machines, then it is not there and you will have to install it yourself in order to then mount a new circuit breaker. This is common today.
The existing old circuit breakers are held here by strips that are bolted to the rear wall of the dashboard. There are two of them (one at the top and one at the bottom) and they simultaneously hold all the machines. To dismantle the old machine, you need to unscrew the upper bar and loosen the lower one. Only first unscrew all the wires, since it will be inconvenient to do this by weight. Also note that the suitable wires will be energized. Also, be careful, as at this point all circuit breakers are loose. Do not unscrew the lower bar at all so that they do not fall. Below in the photo I have signed where that is, but new machines have already been installed here. Unfortunately, I do not have a photo with old machines yet. As will be sure to lay out.
So, we dismantled the old machines. Now you need to install new ones. To do this, you need to install a DIN rail in the vacant space. This is how it is done. The length of the free space is measured and the rail of the required length is cut off with a hacksaw for metal. It is placed horizontally in the center, where the middle of the old machines was. To do this, drill two holes with a 1-2 mm 2 drill with a cordless screwdriver. If you only have a drill powered by the network, then do not take up this business, since the apartment will be de-energized, and this electrical appliance will not work for you. But although as an option, you can throw the carrier from the neighbors. Now we fix the DIN rail in the shield with two metal screws. Next, we install the circuit breaker as I described above and connect the wires.
I also often hear the question: from which side should the incoming and outgoing wires be installed from above or from below? The PUE has recommendations on this matter. The incoming wire must be connected to a fixed power contact, i.e. above. Please always do this, because then after you more than one electrician will rack their brains when they open the flap. We come to the machine from above, and we leave into the apartment from below. May it always be so. Although in existing storey distribution boards in old houses, power comes to the machines from the bottom and goes to the apartments from the upper terminals. Therefore, be careful.
Don't forget to smile:
Wife to husband:
- I asked you to drive 2 nails into the wall!
- And I drove it!
- Has hammered in? .. And where should I turn on the iron now?
Automatic switches (in everyday life, abbreviated as "automatic machines") are a type of switching and control equipment that performs three functions: turning on and off electrical equipment (the task of a conventional switch); disconnection of operating equipment from the network during a sudden and sharp increase in current occurring in the electrical network during a short circuit; shutdown of the operating equipment at a time that is safe for its operation when overload currents appear in the network and abnormal voltage drops in the network that appear during the connection of powerful electrical appliances and electric motors.
The first type of circuit-breakers, which have a housing with ventilation openings, are used in normal environments with reduced dust and moisture. The cast case of the latter provides a higher level of protection, which allows the use of switches in extreme conditions.
Modular is a size-standardized air option.
The dimensions of the modular switch are multiples of 17.5 mm across the width of the case. Due to the versatility and ease of installation, modular machines are widely used in the power supply of residential premises.
How to connect the machine correctly - we do everything in order
In houses built 25-30 years ago, a power supply system was used, in which the "zero" protective conductor was simultaneously a "zero" worker. In modern housing, the functions of protection and working wiring are separate. European plugs make the process of choosing machines dependent on the type of power supply system.
The circuit breakers can be mounted on a standard DIN rail or on a panel, and enclosures are available for both. For the first method, a mounting bracket and a latch are provided on the modular AB. For the second on the air circuit breaker case, there are mounting holes - sockets for fastening to bolts.
The modular switch is attached with one hand push: hooked - pressed - the latch was locked.
For air in the panel, you need to drill holes for the bolts. Fasteners must be equipped with rubber gaskets and sealing washers. For high-power air switches, rubber gaskets can be made from plastic.
One of the options for using multi-tariff metering devices is installation. They allow you to control the costs of consumed electricity and, therefore, save on utility bills.
In the cabinet, the circuit breakers are connected according to the "hierarchy". A cable from an external source is fed into the top, wires are routed through the territory through the lower outlet holes.
If all loads are evenly distributed, then the function of protection against unexpected power imbalances will fall into neutral. For the correct connection of the circuit breaker, it is recommended to use quality materials. All wire connections must be carefully tightened in the terminals. When connecting several cables, their contacts must be stripped and tinned. For a better connection, sealing and insulation (plastic tips) is recommended. Don't skimp on the cost of machines and insulation.
A video with some nuances to consider when installing AB
A modern switchboard in a home must be equipped with protective equipment such as a circuit breaker. To correctly connect the machine in the dashboard, you need to know the rules and features of the procedure.
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What is a circuit breaker and what is it for?
The circuit breaker is a small lever mounted in a panel. Its principle of operation is that it allows you to turn off the electricity supply manually or automatically.
Automatic shutdown is necessary in the following cases:
- short circuit;
- overloading the supply of electric current.
In other words, such devices cut off electricity at a current exceeding the short-circuit power.
Classification
Before buying a circuit breaker, an electrician must decide on the number of poles. This indicator depends on the phases of the network.
The machines are subdivided according to the number of poles:
- single-pole;
- bipolar;
- three-pole;
- four-pole.
Single-pole and double-pole machines are installed in a single-phase network. Three-pole and four-pole are suitable for a three-phase network.
The growmir channel talks about self-installation and connection of the machine to the bagger.
How to choose a machine?
The correct choice of a switchboard machine is a guarantee of balanced operation of the entire electrical circuit in an apartment or other room.
- Legrand;
- Hager;
- Merlin Green;
- Schneider Electric;
When buying a circuit breaker, experts recommend paying attention to the labeling, which contains all the information about the product.
When planning the choice of a device, you need to pay attention to the parameters:
- The magnitude of the rated current. The higher it is, the more voltage is required to automatically turn off the machine. The parameter is selected based on the cable cross-section, and not on the load power.
- Number of poles. This parameter is selected based on the number of phases. The number of slots for the machines corresponds to the number of poles.
Do-it-yourself installation of a circuit breaker in an electrical panel
When installing the machine in an electrical panel, you need to be guided by the rating of the device and the cable cross-section, which is determined based on the maximum wiring load.
Before installation, evaluate:
- rated mains voltage;
- maximum current;
- rated current.
To calculate the load, add up the total power of energy consumers (sockets, household appliances, etc.) and calculate the current power according to the formula below. Knowing this parameter, they decide which machines to connect.