It is difficult to imagine a switchboard without modern modular protection devices such as circuit breakers, residual current devices, differential circuit breakers and all kinds of protection relays. But these modular devices are not always connected correctly and reliably.
In view of the maintenance of electrical panels, I sometimes have to deal with errors in connecting the circuit breakers that are installed in them. It would seem, how can you incorrectly connect a conventional single-pole circuit breaker? I stripped the cable to a certain length, inserted it into the terminals, and tightened the screws securely.
But as strange as it sounds, most people have "gnarled" hands and the build quality of the shields leaves much to be desired. Although in fact we all make or have made mistakes in this or that industry, and as the well-known proverb says: "He who does nothing is not mistaken."
Greetings to all friends on the site "Electrician in the House". In this article, we will consider and analyze several options for the most common and gross mistakes.
Connecting vending machines in the dashboard - top or bottom entry?
The first thing I would like to start with is the correct connection of the machine in principle. As you know, the circuit breaker has two contacts for connecting movable and fixed. Which pins do you need to connect power to the top or bottom? To date, there have been a lot of controversies on this matter. On any electrotechnical forum, there are a lot of questions and opinions on this matter.
Let's turn to the regulatory documents for advice. What does the PUE say about this? In the 7th edition of the PUE, clause 3.1.6. said:
As you can see in the rules it says that supply wire when connecting machines in the shield should be connected, as a rule, to fixed contacts. This also applies to all ouzo, difavtomats and other protection devices. From this whole clipping, the expression "as a rule" is not clear. That is, it seems, as it should, but in some cases there may be an exception.
To understand where the movable and fixed contact is located, you need to imagine the internal structure of the circuit breaker. Let's look at the example of a single-pole machine where the fixed contact is located.
Before us is an automatic machine of the BA47-29 series from iek. From the photo it is clear that its fixed contact is the upper terminal, and the moving contact is the lower terminal. If we consider the electrical designations on the switch itself, then it is also clear here that the fixed contact is on top.
Circuit breakers from other manufacturers have similar markings on the case. Take, for example, an automatic machine from Schneider Electric Easy9, it also has a fixed contact on top. For Schneider Electric RCDs, everything is similar on top there are fixed contacts, and on the bottom there are movable ones.
Another example is protective devices from Hager. On the case of the hager circuit breakers and RCDs, you can also see the designations, from which it is clear that fixed contacts are on top.
Let's see, from the technical point of view, is there a value, how to connect the machine from above or below.
The circuit breaker protects the line against overloads and short circuits. When overcurrents appear, the thermal and electromagnetic release located inside the housing react. From which side the power will be connected from the top or from the bottom to trip the releases, there is absolutely no difference. That is, we can say with confidence that the operation of the machine is not affected by which contact will be supplied with power.
In truth, I must say that manufacturers of modern "branded" modular devices, such as ABB, Hager and others, allow the power supply to be connected to the lower terminals. For this, the machines have special clamps designed for comb tires.
Why, in the PUE, it is advised to connect to fixed contacts (upper)? This rule is approved for general purposes. Any educated electrician knows that when performing work, it is necessary to remove voltage from the equipment on which he will be working. "Climbing" into the flap, a person intuitively assumes presence of a phase on top of the machines... Having disconnected AB in the dashboard, he knows that there is no voltage at the lower terminals and everything that leaves them.
Now let's imagine that an electrician, Uncle Vasya, performed for you, who connected a phase to the lower contacts AB. Some time has passed (week, month, year) and you need to replace one of the machines (or add a new one). Uncle Petya, an electrician, comes in, turns off the necessary machines and confidently climbs under tension with his bare hands.
In the recent Soviet past, all machines had a fixed contact at the top (for example, AP-50). Now, by the design of modular AB, you cannot tell where is the movable, and where is the fixed contact. At AB, which we considered above, the fixed contact was located on top. And where are the guarantees that the fixed contact of the Chinese machines will be located on top.
For those who disagree with me, the question is about filling, why on electrical circuits the power to the machines is connected to fixed contacts.
If we take, for example, a conventional RB-type switch, which is installed at every industrial facility, then it will never be connected upside down. The connection of power to switching devices of this kind is supposed only to the top contacts. I turned off the switch and you know that the lower contacts are without voltage.
We connect the wires to the machine - a cable with a monolithic core
How do most users connect the machines in the dashboard? What mistakes can be made while doing this? Let's take a look at the most common errors here.
Error - 1. Contact with insulation.
Everybody knows that before you need to remove the insulation from the connected wires. It would seem that there is nothing complicated here, I stripped the core to the required length, then we insert it into the clamping terminal of the machine and tighten it with a screw, thereby ensuring reliable contact.
But there are cases when people are at a loss why the machine burns out when everything is connected correctly. Or why the power in the apartment periodically disappears when the wiring and filling in the dashboard are completely new.
One of the reasons for the above hitting wire insulation under the contact clip of the circuit breaker. Such a danger in the form of poor contact carries a threat of melting of the insulation, not only of the wire, but also of the machine itself, which can lead to a fire.
To exclude this, you need to follow and check how the wire is tightened in the socket. Correct connection of the circuit breakers in the switchboard should exclude such errors.
Error - 2. You cannot connect several conductors of different cross-sections to one AB terminal.
If the need arose connect several machines standing in the same row from one source (wire) for this purpose, a comb bus is the best fit. But these tires are not always at hand. How to combine several group machines in this case? Any electrician, answering this question, will tell you to make homemade jumpers from the cable cores.
To make such a jumper, use pieces of wire of the same cross-section, or it is better not to break it at all along its entire length. How to do it? Without removing the insulation from the wire, form a jumper of the desired shape and size (according to the number of branches). Then we strip the insulation from the wire at the bend to the desired length, and we get an unbreakable jumper from a single piece of wire.
An example of connecting circuit breakers with jumpers from different cable cross-sections. The first automaton receives a "phase" with a 4 mm2 wire, and other automata already have jumpers with a 2.5 mm2 wire. The photo shows that jumper made of wires of different cross-sections... As a result, poor contact, temperature rise, insulation melting not only on the wires, but also on the machine itself.
For example, let's try to tighten two wires with a cross section of 2.5 mm2 and 1.5 mm2 in the terminal of the circuit breaker. No matter how hard I tried to provide reliable contact in this case, nothing worked for me. A wire with a cross section of 1.5 mm2 dangled freely.
Another example in the photo is a difavtomat, into the terminal of which two wires of different cross-sections were stuck and tried to tighten the whole thing securely. As a result, the wire with a smaller section dangles and sparks.
Error - 3. Forming the ends of wires and cables.
This point most likely refers not to an error, but to a recommendation. To connect the veins of outgoing wires and cables to the machines, we remove the insulation from them by about 1 cm, insert the bare part into the contact and tighten with a screw. According to statistics, 80% of electricians are connected this way.
The contact at the junction is reliable, but it can be further improved without wasting time and money. When connected to vending machines solid core cables Make a U-bend at the ends.
This formation of the ends will increase the contact area of the wire with the clamping surface, which means that the contact will be better. P.S. The inner walls of the contact pads AB have special notches. When the screw is tightened, these notches cut into the core, which increases the reliability of the contact.
Connecting stranded wires to the machine
For wiring switchboards, electricians often prefer a flexible wire with a multi-wire conductor of the PV-3 or PuGV type. It is easier and easier to work with it than with a monolithic vein. But there is one peculiarity here.
The main mistake that beginners make in this regard is connecting stranded wire to the machine without termination... If you compress a bare stranded wire as it is, then when tightening the veins are squeezed and break off, and this leads to a loss of section and deterioration of contact.
Experienced "experts" know that it is impossible to tighten the bare stranded wire in the terminal. And for the termination of stranded conductors, you need to use special tips NSHV or NSHVI.
In addition, if there is a need to connect two stranded wires to one terminal of the machine for this you need to use the double tip NShVI-2. With the help of NShVI-2 it is very convenient to form jumpers for connecting several group machines.
Soldering wires under the terminal of the machine - ERROR (error)
Separately, I would like to dwell on this method of terminating the wires in the shield as soldering. So human nature is arranged that people try to save money on everything and do not always want to spend money on all kinds of tips, tools and all kinds of modern small things for installation.
For example, consider the case when Uncle Petya, an electrician from the housing office, conducts the wiring of the electrical panel with a stranded wire (or connects outgoing lines to the apartment). He does not have NSHVI tips. But there is always a good old soldering iron at hand. And the electrician Uncle Petya does not find any other way out how to irradiate the multi-wire conductor, stuffs the whole thing into the contact terminal of the machine and tightens it heartily with a screw. Why is this dangerous?
When assembling switchboards, DO NOT solder and tin the stranded conductor... The fact is that the tinned compound begins to "float" over time. And in order for such a contact to be reliable, it constantly needs to be checked and tightened. And as practice shows, this is always forgotten. The soldering begins to overheat, the solder melts, the junction is weakened even more and the contact begins to "burn out". In general, such a connection can cause a FIRE.
Therefore, if a stranded wire is used during installation, then NSHVI tips must be used to terminate it.
Circuit breakers, also known as packers or automatic machines, are switching devices whose task is to supply current to the elements of the power grid, and in case of a malfunction, to automatically de-energize. They are usually mounted in a switchboard and protect the circuit from damage caused by excessive loads, voltage drops, and short circuits. In this material, we will talk about how this equipment is classified, what are the features of its operation and how to correctly connect the machines in the electrical panel.
Classification of circuit breakers
Today these devices are sold in a huge range. They differ among themselves in the following characteristics:
- Main circuit current. It can be variable, permanent, or combined.
- Control method. The equipment can be operated manually or by means of a motor drive.
- Installation method. Devices are plug-in, retractable or stationary.
- Release type. These elements can be electronic, electromagnetic and thermal, as well as semiconductor.
- Body type. It can be modular, cast or open.
- Working current indicator. Its value can be from 1.6 A to 6.3 kA.
Modern machines are distinguished by a complex network protection mechanism. They have additional capabilities, which include:
- The ability to open the electrical circuit at a distance.
- Presence of signal contact groups.
- Automatic operation of a protective device in the event of a voltage drop to a critical value.
Step-by-step diagram for choosing a circuit breaker in the video:
Packets can be of various standard sizes, and with their help it is possible to protect electrical networks not only in apartments and private houses, but also in large objects. These devices are produced both in Russia and abroad.
In domestic conditions, modular circuit breakers, small and lightweight, are most often used. They got the name "modular" due to their standard width, which is 1 module (1.75 cm).
In order to protect the electrical circuits of buildings, the following types of switches are installed:
- Differential.
- Automatic.
RCDs, as they are abbreviated as residual current devices, prevent electric shock to a person who touches the conductor, and prevent the surrounding objects from igniting in the event of an electricity leak, which can occur if the insulation of cables is damaged.
Circuit breakers protect circuits from short-circuit and allow you to manually turn on and off the power. The most advanced protective device is the differential circuit breaker. It combines the capabilities of a residual current device (RCD) and a conventional circuit breaker. This bag is equipped with built-in protection against excessive electron flow. It is controlled by a differential current.
In single-phase power grids, single-pole and double-pole machines can be installed. The choice of the bag is influenced by the number of wires in the electrical wiring.
Circuit breakers: device and principle of operation
Before considering the procedure for connecting the circuit breakers in the electrical panel, we will figure out how they are arranged and by what principle they are triggered.
The product includes the following elements:
- Frame.
- Control system.
- Top and bottom terminals.
- Switching device.
- Arc extinguishing chamber.
Fire-resistant plastic is used as material for the body and control system. The switching device has moving contacts, as well as fixed ones.
An arcing chamber is installed on a pair of contacts, which are the pole of the bag. When the contacts are broken under load, an electric arc arises, which is extinguished by the camera. The latter consists of steel plates, isolated from each other and at the same distance. The plates of the chamber contribute to the cooling and extinction of the electric arc, which appears in case of malfunctions. The machines can have one, two or four pairs of contacts.
Two-pole machines have two pairs of contacts: one is movable, the other is fixed.
Such a switch is equipped with a position indicator, which makes it easy to find out if the machine is on (red light) or off (green).
The principle of operation of circuit breakers in the video is clearly visible:
Release
To turn off the machine in case of emergency, the device is equipped with a release. There are several types of these mechanisms, which are structurally different from each other and work according to different principles.
Thermal release
Structurally, this element includes a plate pressed from two different metals with an unequal coefficient of nonlinear expansion, which is connected to a circuit under load and is called bimetallic. During operation of the release, the flow of electrons passing through the plate heats it up.
Since the expansion coefficient of the metal is less than that of the plate, it bends towards it. When the current rating exceeds the permissible value, the curved plate, acting on the trigger, turns off the machine. If the ambient temperature deviates from the norm, the switch also trips.
Magnetic release
A release of this type is a coil with an insulated copper winding and a core. Since the load current flows through it, it must be connected to the circuit in series with the contacts. If the load current exceeds the permissible rating, the core will move under the influence of the magnetic field of the release and, by means of a tripping device, will open the contacts of the bag.
Selective circuit breakers with semiconductor release
These devices are equipped with a special panel on which the time for the machine to be turned off is set. They provide a time delay in the event of a short circuit, which makes it possible to turn off the emergency section in the event of an abnormal situation, without interrupting the power supply to the object.
A circuit breaker without a release is called a disconnector.
How to choose a machine?
Before starting the installation of protective circuit breakers, you need to choose them, as well as understand the intricacies of the connection. People who want to know how to wire a circuit breaker are asking various questions. For example, before or after the meter, are the machines connected in the switchboard? Should an input machine be installed? These and other connection nuances are of interest to users.
The main parameters of the circuit breakers
The characteristics of circuit breakers include:
- Rated current (in Amperes).
- Mains operating voltage (in Volts).
- Maximum short-circuit current.
- Ultimate switching capacity.
- Number of poles.
The limiting switching capacity is characterized by the maximum allowable value at which the circuit breaker is capable of operating. The PCR of household devices can be 4.5, 6 or 10 kA.
When choosing, they are most often guided by such basic indicators as the short-circuit breaking current, as well as the overload current.
The cause of overload is the connection of devices with an excessively high total power to the mains, which leads to an excess of the permissible temperature of the contact connections and cables.
Considering this, it is necessary to install a packet bag in the circuit, the value of the shutdown current of which is not less than the calculated one, and it is better if it slightly exceeds it. To determine the estimated current, you need to summarize the power of the devices that are supposed to be connected to the circuit (for each of them this indicator is in the passport). The resulting number must be divided by 220 (the standard value of the voltage in a household network). The result obtained will be the value of the overload current. It should also be borne in mind that it should not exceed the current rating that the wire can withstand.
The magnitude of the short-circuit breaking current is the indicator at which the circuit breaker is turned off. The calculation of the short-circuit current is carried out when designing a line according to formulas and reference tables, as well as using special equipment. Based on the obtained value, the type of protection is determined. On small objects and in household networks, type B or C machines are used.
Do-it-yourself installation of a circuit breaker in an electrical panel
First of all, you need to decide on the connection of the power wires, and only after that figure out how to connect the machine to the network. If you do not know whether the supply conductors should be connected above or below the bag, refer to the requirements of the PUE, which are the main guiding document when carrying out electrical work.
The Rules clearly stipulate that the power cable must be connected to fixed contacts, and this requirement must be met in any circuit for connecting circuit breakers. In any modern device, fixed contacts are located on top.
For installation, you will need control devices and a tool, which includes:
- Assembly knife.
- Screwdrivers (Phillips and slotted).
- Multimeter or indicator screwdriver.
So how do you connect the machine correctly? Consider the installation of circuit breakers in single-phase networks.
Two-phase and three-phase connections are more complicated and should be done by a specialist.
Single pole circuit breaker
Installation is carried out in a network where two cables are used to make the input: zero (PEN) and phase (L). Such a system exists in old buildings. The supply conductor is connected to the input terminal of the machine, then from the output it passes through the meter, after which it is wired to protective devices of specific groups. The supply zero cable to the PEN is also fed through an electric meter.
The use of one, two and three-pole circuit breakers in the video:
Two-pole automatic machine
We consider the installation of a protective device in a single-phase network, where three conductors are used for input: phase, neutral and grounding cable. The input terminals, marked on the device with numbers 1 and 3, are located at the top of the machine, and the output terminals (2 and 4) are at the bottom.
The supply cable fits into the input terminal 1 and is securely fixed to it. In the same way, the neutral wire is attached to terminal 3. The phase passes through the electricity meter. Power is distributed evenly across the switch groups. From terminal 4, the zero cable is connected to the N bus, passing through the counter and the RCD.
Connecting wires
A passport is attached to any circuit breaker, which describes how to correctly connect the wires to its terminals. The document contains all the necessary information - from the cross-section of the cables and the type of their connection to the length of the stripped part of the conductor.
Stripping the ends of the wires for connecting household machines is done with a mounting knife by about 1 cm.You can distinguish the conductors by their color coding:
- The phase cable is white or brown.
- The neutral wire is black, blue or light blue.
- The grounding conductor is green.
After stripping the end of the wire with a knife, insert it into the contact clamp and secure with the fixing screw. The screws are tightened with a screwdriver. After fixing the wire, you need to twitch a little to make sure it is securely fixed. If a flexible wire is used to connect to the bag, then in order to increase the reliability of the connection, special lugs should be used.
In order for the installation of the machines in the switchboard and the connection of cables to them to be performed correctly, you need to remember about common mistakes and avoid them during operation:
- Contact with the insulating layer.
- Too much force when tightening, which can lead to deformation of the case and, as a result, to breakdown of the machine.
Often, several protective devices are installed in a switchboard at once. To connect them, inexperienced specialists use jumpers.
In principle, this is not a mistake, but nevertheless, in this case, it is better to use a special tire cut to the required size - the so-called comb. With its help, the wires are connected to the bags in the desired sequence.
Features of connecting the self-supporting insulated wire to the input machine
Self-supporting insulated wire is widely used to transfer electricity to the home network from overhead power lines instead of conventional cable. With all the advantages of this conductor, the connection of the self-supporting insulated wire to the circuit breaker should not be made directly, since during operation the aluminum begins to "float" and the insulation burns out. Ultimately, this leads, at best, to the failure of the machine, and at worst - to a fire. The easiest way to avoid such a nuisance is to connect the self-supporting insulated wire to the machine through a special adapter sleeve.
Such a device provides a transition from aluminum wire to copper. You can buy it in a specialized store.
Step-by-step installation of the machine - in the following video:
Conclusion
In this article, we figured out the question of how to properly connect the circuit breakers in the electrical panel, and also considered the types of these devices and the features of their operation. Using the information provided, you can independently install the package and connect it to your home network. Naturally, with this procedure, you must strictly follow the rules of electrical safety, as with any work related to electricity.
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 reliable clamping of the bolted contact connection;
- Pliers;
- Insulating material (electrical tape).
Of course, all these rules and techniques apply to connecting and installing 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 obtain 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 supply 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 during 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. All 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 for the safe design 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 done with any voltage probe or indicator. It must be remembered that these works are classified as hazardous works and can cause 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 wire. 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 twisting, 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 not be 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 the 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
The most common means of protecting lines and electrical appliances are circuit breakers. When installing them, you must follow the basic rules.
- Entry at the top of the machine, exit at the bottom.
- The enable flag when the machine is turned on should be directed upwards.
- There should be no exposed wire sections.
How to connect a differential machine
The differential circuit breaker combines line protection against overloads and short circuits, as well as circuit breakers, and protection of a person from electric shock, like an RCD.
The case design does not differ from automatic devices or RCDs, which makes it possible to install a differential automatic device in standard boxes using a DIN rail.
Connecting a differential circuit breaker also resembles connecting a circuit breaker with a few exceptions - the mandatory observance of two rules.
- It is necessary to observe the phasing of the connected wires. On the case of the differential machine, the designations of the zero and phase inputs are applied, which must be taken into account during installation.
- The neutral wire connected at the output of the differential machine is used only with the line that the device protects.
Differential machines are very reliable and unpretentious, but deviation from these rules does not guarantee the correct operation of the device.
For a single-phase network, the use of two-pole circuit breakers is preferable to single-pole ones. The reason is simple - when a voltage appears on the neutral wire, one movement of the flag completely breaks the circuit, preserving both the line and the electrical appliances connected to it. The cabinet design of the two-pole switch allows mounting on a standard DIN rail.
It should be borne in mind that the width of such an automatic machine is, as a rule, twice as large as a single-pole machine. The upper contact pair is designed to connect the phase and neutral wires.
There are no strict rules for the location of the phase and neutral wires, but in the case of connecting a number of two-pole machines, it is necessary to adhere to the same tactics.
Choosing, for example, the left contact for the phase wire, all other machines must be connected as well. The left contact is phase, the right one is zero.
The stripped wires are fixed in the contacts using screw clamps. In this case, there should be no bare sections of the wire. Do not forget that there is a very small distance from the phase to the neutral wire and there is a possibility of a short circuit in the absence of insulation.
The most commonly used single-pole circuit breakers are reliable, easy to install and provide the necessary line protection against overloads and short circuits.
When connecting the circuit breaker, it is important that the body of the machine is securely fastened and, when switched on or off, does not fall off the attachment point.
To do this, use a DIN mounting rail or special boxes with pre-installed rails in the case. The machine is mounted on a rail using a spring-loaded latch at the bottom of the case.
After installing the machine, a wire is connected to it. The upper terminal of the machine is responsible for the voltage input, and the lower terminal for the output. The wires laid and fixed on the wall are led to the machine and stripped.
In this case, it is imperative to comply with the condition of insulation integrity everywhere, except for terminal blocks. The length of the stripped ends is quite enough in 1-1.5 cm.
The phase suitable and outgoing wire is clamped in the terminals of the machine, while the zero wire can pass in transit through the box or, if necessary, fixed on a zero rail.
Leading and outgoing wires must be laid in such a way as to avoid excessive lengths. Wires are laid parallel to each other and, if possible, all bends are carried out at right angles.
After installing the machine and checking all connections, the first switching on must be carried out without a connected load on the line.
Circuit breaker (VA)- a device capable of disconnecting, without human intervention, electricity for consumers, in the event of an overload or short circuit, in order to protect the electrical circuit from further destructive consequences and prevent fire.
The circuit breaker will stop the supply of power to the entire apartment or de-energize a separate group in the electrical network, until the cause is clarified and eliminated.
Functionality of the circuit breaker
During an overload of the electrical network, the power cut-off circuit breaker can operate differently, depending on whether the cable is hidden or open? What is the ambient temperature? The machine can trip during an overload from several minutes to several hours. As soon as the load rises to the specified rated value of the circuit breaker, for example, if the machine at the input is set to 40A, as soon as the current increases to 40 Amperes (8.8 kW), the machine will work.
You have purchased and installed a washing machine - it's great! But soon you got annoyed - the circuit breaker was often knocked out. What to do? How to be? It is not advised to increase the rating of the circuit breaker, for example from 16A to 25A, the old aluminum wiring will work to its limit. Which exit? It is better to separate the washing machine from the general group in the network and conduct a separate three-core copper wiring from the switchboard and set the circuit breaker to 20A, if the rated power of the washing machine is 2200 W.
Which circuit breaker to install?
When calculating the rating of the circuit breaker, start from the cross-section of the wire, the temperature load, as well as from how the wiring will be laid - hidden or open. Consider not the limiting current transmission, but "quiet", ie. there must be a good margin of safety, or, more simply, so that the conductor does not warm up due to the overrated value of the machine. In another case, if the conductor has a large throughput, it is not worth underestimating the value of the machine - it will constantly knock it out.
Sectional circuit breakers are "set" on a plate called a din rail built into the switchboard. Circuit breakers are 1P (pole), 2P, 3P, 4P. The last two are installed in a three-phase network. In a single-phase network, a 2P machine is most often installed at the input.
The nominal current strength of the circuit breakers in everyday life: 2A, 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A.
Where are circuit breakers not installed?
On separate groups they put 1P, 2P is possible, but this is not economical both in terms of money and in the space of the panel room. It is known that in France, according to the rules and regulations, only two-pole switches are installed. This is not to say that they do not save space in the control room. The fact is that, French double-pole switches are like our single-pole ones. Do not set the 1P circuit breaker to zero. It is not recommended to break the zero separately from the phase. All neutral conductors are attached to a common neutral bus. You can break the zero simultaneously with the phase, in this case you need to put a 2P machine.