Breakdowns of electrical household appliances occur quite often, because any electrical unit, when created, is designed to work with a certain level of electricity, i.e. on specific indicators of current strength and voltage in connection networks. Therefore, if these standards are exceeded, an emergency situation may occur.
The use of expensive home appliances, aggressive natural and atmospheric phenomena, and a not too high level of laying power lines make it vital for apartment and house owners to take measures to protect against electrical overvoltage in a private home and minimize possible consequences.
Where does overvoltage come from?
The planning and construction of many high-rise buildings a couple of decades ago was carried out without taking into account today's variety of household electrical equipment: microwaves, multi-compartment refrigerators, high-power irons and other electrically powered devices. Therefore, maximum electricity consumption in the mornings and evenings has a detrimental effect on the operation of the entire electrical network in any home.
Electricity flowing through a cable or wire that is unable to withstand such a load causes it to become abnormally warm during the day and cool during the evening. Due to the laws of physics, the conductor weakens as it becomes wider or narrower. The contacts in the panel on the first floors or in the single input-distribution device in the house noticeably weaken. Also, zero contacts can burn out, which leads to a voltage drop from 110 to 360 volts on all floors, above the floor with burnt out contacts.
Overvoltage in the electrical network can occur as a result of a lightning discharge hitting a power line, substation or elements of a house, and the current strength is simply enormous, about 200 kiloamperes. When lightning enters the lightning rod and then passes along the ground loop, an electromotive force is generated in conductor materials, measured in kilovolts.
Welding work or the simultaneous switching on of electrical appliances by many neighbors or the connection/disconnection of a powerful consumer can also cause a sharp surge in voltage. To protect expensive electrical equipment and the entire private home, network surge protection is necessary.
Features of home electrical wiring protection
Organizing protection against emerging high voltage is one of the key issues when laying an electrical network in a residential building. It is carried out using special transformers and network filters. In many houses, automatic switches are installed on the floor panels, which protect against electric currents during short circuits and temporary overloads.
When high loads are possible, all devices that protect networks from overvoltage must have automatic shutdown devices and switches that respond to changes in current levels. As a rule, the most reliable protection against such surges is placed on the input power wire, since it is this that experiences the greatest impact during load peaks.
The surge protection circuit for a home electrical network can be simple or multi-level. Simple - represented mainly by overvoltage relays in floor panels, and multi-stage (combined, protecting both from household power surges and from pulsed ones during thunderstorms) - SPD, i.e. Surge protection devices. Such devices are most often found in private homes.
Note! Electronic devices fail due to both increased and decreased voltage in the network (for example, refrigerators are difficult to start, which negatively affects their further operation).
The insulating layers of home electrical networks are designed, as a rule, for standard 220V, therefore, if the voltage increases many times, a spark jumps in the dielectric layer, which can provoke an electric arc and further fire.
To prevent negative consequences, the following protections are used, operating according to the following principles:
- when there is a sharp unscheduled increase in voltage, the electrical circuit in the house or apartment is disconnected;
- outputting the received excess electrical potential from electrical appliances by transferring it to an earth circuit.
If the voltage rises slightly (for example, up to 380 volts), various stabilizers come to the rescue. However, their protective capabilities are quite limited - they are more designed to maintain specified operating values in electrical networks.
When designing protection for a private home, various design solutions and their technical characteristics are considered. It is necessary to take into account the principles of forming a base of surge limiters (SPS). For example, gas-filled arresters, after the pulse has passed, pass through the so-called. accompanying current, the voltage of which is comparable to a short circuit. For this reason, they themselves can be a source of ignition, and they cannot be used for protection against electrical breakdown.
For home networks, varistor protection devices (semiconductor resistors) are most often used - rheostats composed of varistor “tablets” made from a mixture of oxides of zinc, bismuth, cobalt and others. During normal operation of the electrical network, such a circuit breaker allows microscopic leaks, and when a pulse of high voltage passes through, it is capable of instantly switching to the “tunnel” mode and “draining” more than a thousand amperes in a very short period of time, since the resistance on this device decreases with increasing current strength, after which there is a quick return to normal “combat readiness”.
Electrical wiring resistance classes
All electrical appliances in domestic buildings are divided into four main categories, depending on the maximum withstand overvoltage:
- IV category – up to 6 kilovolts;
- III category – up to 4 kilovolts;
- Category II – up to 2.5 kilovolts;
- Category I – up to 1.5 kilovolts.
In accordance with these categories, a protection system is built, which is abbreviated as Uzo (residual current device) with overvoltage protection; for marketing purposes they are most often called limiters, and other names are also used. Limiters are mounted in the direction of movement of a possible impulse. So, in the section from the input panel there is a 6-kilovolt pulse, in the first zone it is reduced by an overvoltage limiter to 4 kilovolts, in the next zone it drops to 2.5 kilovolts, and in a residential area using a category III surge protector the pulse potential is reduced to 1. 5 kilovolts. Protection devices of all classes function in a complex, consistently lowering the potential to normal values, which can be easily handled by the insulation of home electrical wiring.
Important! If at least one link of this protective chain malfunctions, an electrical breakdown in the insulation may occur, which will lead to failure of the final electrical device. Therefore, it is necessary to periodically check the serviceability of each element of the residual current devices.
Main devices of the protection system
One of the best ways to save the electrical network from voltage surges is to install a stabilizer that meets the technical specifications. These are not cheap devices, and they are not always used, since the voltage in the networks is already quite stable.
Voltage control relays also help eliminate network instability. In the event of a break in the neutral core and a short circuit in sagging cables, such a relay can turn on protective functions even faster than a stabilizer, it only takes 2-3 milliseconds.
Such relays are very compact - they require less space for installation than stabilizers, they are easily installed on a simple DIN rail, the cables are connected simply (unlike the installation of stabilizers, when they are forced to wedge themselves into the electrical network or install a special box for it). Stabilizers hum noticeably, so it is not advisable to install them in residential areas, but relays operate almost silently. In addition, devices that control electrical potential differences consume very little electricity. The price for such relays is several times lower than those for stabilizers.
The operating principle of the control relay is that with a constant supply of electric current, the device determines the potential difference and compares it with permissible values. If the indicators are normal, the keys remain open and current continues to flow through the network. If a powerful impulse passes, the keys are instantly closed and the power supply to consumers is cut off. Such a quick and unambiguous reaction helps to protect all connected household appliances.
Additional Information. Returning to normal mode occurs with a certain delay, controlled by a timer. This is necessary to ensure that large electrical appliances, such as refrigerators, air conditioners and others, turn on in compliance with the rules and technical settings.
The relay is connected via a phase cable, while the neutral cable is included in the internal circuit for power supply.
There are two methods: end-to-end connection (directly) or using a contractor device for communication. It is optimal to connect the relay mechanism before connecting the meter, which will also ensure its protection against overvoltage. However, if there is a seal on the metering device, you will have to install a relay behind it.
Pulse overvoltages in the electrical network of private houses occur due to thunderstorms with lightning or switching surges. For the safety of electrical wiring, special SPD devices are used. As a rule, these are nonlinear surge suppressors (OSN), stabilizers and potential monitoring relays. Of course, setting up such a system is an expensive undertaking, but its cost is much lower than that of expensive electrical household appliances.
Video
Power surges are a common problem in suburban communities. Most often it occurs during cold weather, when many people use electric heaters. Breakdown of household appliances, accidents on the line - it is better to protect yourself from this in advance. In our material we tell you what devices will save your home from harm and help you wait out the “end of the world.”
Voltage surges primarily harm those household appliances that have electric motors and compressors - refrigerators, air conditioners, washing machines, etc. If there is a lack of power, their motors heat up but do not spin, which ultimately leads to a winding burnout. Low voltage dramatically reduces the efficiency of space heaters, microwave ovens, and incandescent light bulbs.
But all this is only half the story. Constant drawdowns indicate that the network is operating in emergency mode, with overloads. This means that sooner or later something will burn out in the network equipment. The most dangerous situation is the burning out of the “zero”. In this case, the voltage on the “phase” can sharply increase to 380 volts. Then, of course, all working electrical appliances will burn out.
It must be borne in mind that a break in the “zero” is not always a consequence of overloads. Accidents also happen due to bad weather: icing of wires, falling trees in strong winds, etc.
Voltage relay (RN)
These are smart devices that can break the network if the voltage in it goes beyond the user-specified values.
The most common are electronic relays. They usually have a digital indicator that shows the current voltage and operating mode of the device. Electronic LVs cost up to 5 thousand rubles; as a rule, they operate with a current of up to 16 amperes. This roughly corresponds to the power of electrical appliances of 3 kW (electric kettle + microwave and that’s it). In order for such a relay to protect the entire house, you will have to connect it through electromagnetic contactors (plus the cost of 600 rubles and additional space for 3-4 modules).
Electromechanical relays voltages are considered more reliable and can operate with currents up to 63 amperes (total power of electrical appliances up to 14 kW). Such relays usually do not have digital displays, but only indicator lights.
Please note that the voltage relay must have a higher operating current rating than the circuit breaker after which it is installed. For example, if you are using a 32 A “automatic machine,” then select a 40 A relay. With an electromechanical relay, this condition is easy to fulfill. With electronic it is more difficult. It is necessary to plan well which consumer groups will be protected by which devices.
One more nuance. If you install a single relay to protect the entire house, then during voltage sags you will be left completely without electricity. Protecting the refrigerator from overheating, the relay will turn off the current, and you will not even have light in the rooms. Therefore, for different groups of consumers there should be several relays - with different settings.
A voltage relay is not the cheapest device. Prices start at 2,500 rubles for Chinese samples from little-known manufacturers. However, in some cases, simpler devices can be used instead of relays.
Minimum/overvoltage circuit breakers (MVR).
This device is installed in the electrical panel on a standard DIN rail next to the circuit breaker. The circuit breaker is designed specifically to turn off the “machine” if the voltage goes beyond the limits. For this purpose, the breaker has a special lever, which is inserted into a groove on the body of the “machine”. The switch and breaker must fit together like a key to a lock, so it is better to buy them together.
Breakers cost from 150 to 700 rubles. But this inexpensive solution has its drawbacks. The response threshold is set by the manufacturer and is not adjustable. The most common circuit breaker on the Russian market, RMM-47, has a lower operating threshold of 170 V and an upper threshold of 270 V. This device can protect not very sensitive equipment - electric furnaces, boilers, etc.
Surge protection devices (SPDs).
SPDs are designed to protect the network from the consequences of a lightning strike. If lightning strikes a power line or discharges somewhere very close to it, a voltage surge will form in the network. Over the course of some milliseconds, it increases tens of times higher than the usual 220 volts.
This can be fatal for “smart” equipment that contains electronic control units. By the way, most voltage relays are easily damaged by lightning strikes. Only some have special protection.
For installation in electrical panels, two types of SPDs are produced. The first type is able to withstand direct lightning strikes on power lines. However, it does not completely extinguish the voltage surge, but cuts off, figuratively speaking, only half of the wave. A surge protector of the second type will save you if a discharge occurs somewhere nearby. But it can completely extinguish the voltage wave after a device of the first type.
The ideal option for a country house (especially one built on a hill) is to have both types of surge protectors in the panel. Well, at a minimum you need to install a device of the second type. If lightning hits a power line directly, it will burn itself out, but it will save household appliances.
Prices for SPDs start from 300 rubles.
Network filters
This is perhaps the most popular device for protecting household appliances from power surges. And also the most useless thing.
The direct purpose of a surge protector is to suppress interference in the network that occurs during the operation of some devices. Such devices, in particular, include computer power supplies.
Interference generated by computers can interfere with the operation of stereo systems and televisions (modern technology, as a rule, is not sensitive to this interference, that is, it has built-in surge protectors).
Some models of surge protectors contain fuses or circuit breakers that react to overheating. But this is unlikely to save the connected device from a power surge. Rather, it will save the room from a fire, but only after a short circuit occurs in the electrical appliance.
And only a few network filters have built-in voltage relays. Moreover, these models cost no less than a relay that can protect the entire house.
Surge Protectors
These are the most effective devices for eliminating differences. They are able to “correct” the voltage: increase or decrease it if necessary. But they also have a number of disadvantages - they are bulky, heavy, produce noise typical of transformers and are quite expensive. What do you need to know when choosing a stabilizer?
These devices are relay and electromechanical. Relays can be installed in an unheated room. The quality of their work depends on the number of coils, the so-called “stages”. In inexpensive models there are few steps, and therefore voltage drops are noticeable. Electromechanical ones operate more smoothly, but they make more noise and behave unstably in the cold.
When choosing a stabilizer, it is important to pay attention to whether it has overvoltage protection. If not, then you will have to install a voltage relay in front of the stabilizer.
The peculiarity of the stabilizer is that it itself needs energy. And the lower the input voltage, the more current it “eats off” from the overall pie. This increases energy costs. But this is not the biggest problem.
If the tension in the village often sags and many summer residents have acquired stabilizers, then a real war begins between them. Of course, it is not the summer residents themselves who are fighting, but their devices. As the voltage drops, the stabilizers begin to take more and more energy. As a result, tension drops even more, and the appetite of stabilizers increases. Eventually, some of the devices overheat and shut down. Then the rest have a holiday: the power begins to suffice. But this will not last long until the devices that have left the struggle are rebooted. Then the war for energy begins again. It is clear that in this mode the stabilizer is unlikely to last for many years. For “severe” cases, it is better to provide an autonomous source of power supply.
Gasoline power plant, or gas generator
This device is, of course, not easy. It makes noise, smokes, requires fuel, periodic oil changes, preventative maintenance... But it allows you not to rely on the mercy of electricians and always have light, heat and the Internet in your home.
The main criterion for choosing a generator is power, and you need to take it with a margin of at least 20 percent. A modern home requires at least 10 kW, but if you limit yourself to a kettle, TV and refrigerator, you can keep within 4 kW.
Please note: appliances with electric motors may consume 3-4 times the rated power at startup. For example, a 500-watt refrigerator may require 2 kilowatts to run. By the way, it is advisable to make such calculations when choosing not only a generator, but also a transformer.
But in the case of generators, consider another important point. The vast majority of generators have two output sockets. And the power is divided equally between them. To get 4 kW on one line, you need to have an 8 kW generator.
You can, of course, take current from both sockets. But, as a rule, the wiring in the house is not suitable for this. So if you are just building a house, then immediately divide the energy consumers into two lines in order to use the generator’s power to the maximum.
Uninterruptible power supplies (UPS)
The UPS can be used for autonomous power supply of computers and other office equipment. However, some models can cope with power surges.
The simplest UPSs, also called backup ones, monitor the voltage and when it goes beyond certain limits, switch the computer to battery power. If the voltage constantly fluctuates, then these switchings occur frequently. As a result, the battery quickly fails.
More advanced models - linear-interactive - have a transformer in their housing. During voltage surges, it smoothes out the waves and does not disturb the battery. The battery is used only if the current completely disappears. Therefore, when choosing an IBR, study the nature of the voltage in your outlets in advance.
And may your home be safe!
Everyone has encountered this problem at least once. And for many, unfortunately, voltage surges (higher/lower ratings, phase imbalances) in the home electrical network have become commonplace, and we no longer pay much attention to it, unless they are too large. But equipment (especially imported) is very sensitive to such shortcomings in the power supply - the same heating boilers.
The consequences (not to mention the discomfort) can be the most tragic - from incorrect operation or even breakdown of household appliances to fire of electrical wiring. So what to do if sudden changes in voltage in the power supply network become frequent?
Without knowing what could cause the “illness,” it is pointless to look for healing remedies for it. All sudden changes in the voltage rating are caused by natural or man-made factors (including emergency situations, which are extremely difficult to predict). What is meant?
Instability of substation operation
This is more typical for areas of old buildings.
Initially, the capacities are calculated for a certain load with some margin. But will it be enough for the long term? After all, people are gradually settling in, apartments (private houses) are filled with household appliances, there is a change of owners, the purpose of buildings, and so on - it is impossible to take everything into account. As a result, energy consumption needs are increasing. But the existing power transformer, due to its design features, is no longer able to provide them. This is rarely taken into account, and power engineers practically do not modernize substations (which are the property of resource supply organizations) - it is too expensive and does not promise profit.
Equipment wear and tear
This applies to both the power Tr itself and power lines. The process is completely natural, and there is only one way to get rid of power surges - reconstruction.
One-time shutdowns
It is enough to decommission several fairly powerful consumers (and simultaneously stop their operation), and surges in the network cannot be avoided. This is typical not only for areas in which there are any industrial enterprises, but also for high-rise buildings. If the lines and switchboard equipment are worn out, then in the evening, with a massive shutdown of lights and modern powerful household electrical appliances (for which the wiring in old houses was not originally designed), power surges are more than likely.
Zero break
Such a fault somewhere on the line (substation) is unlikely. The main reason for the jumps is the intervention of a person who does not have the slightest idea about the organization of power supply to buildings and structures. There are three standard power supply schemes for houses, so before you engage in any independent reconstruction, you should clarify which one is implemented in a particular building.
In practice, various “homemade” people try to do everything on their own. Most of our houses are supplied with 1 phase and zero, but... It must be connected to modern devices, especially powerful ones. Some craftsmen, without contacting the management company, try to solve this problem on their own, not knowing all the features of the general house scheme. The result, as a rule, is the same - the common neutral wire burns out. The most common cause of voltage surges in apartment buildings.
Accidents on the line
Their unsatisfactory condition in some areas is only one of the reasons. Strong gusts of wind, icing of wires and their subsequent sagging (or even breakage) - all this leads to short circuits and mechanical damage on the route.
Violations in the ground loop
This may be the same conductor breakage, loosening of the contact, or its oxidation. In apartment buildings, such malfunctions can be caused artificially, by the already mentioned “homemade” ones. Without knowing the circuit and wiring of the conductors, they often confuse “zero” with “ground”.
Low quality of installation work
This applies both to the organization of power supply to private buildings and to high-rise buildings. Often, to restore (remodel) the electrical wiring in an apartment, owners involve low-skilled specialists (acquaintances, “knowledgeable” neighbors, and so on). What did they connect, how, to what? And if they get into the driveway, then everyone can feel the consequences.
Incorrect operation of household appliances
If the model is powerful, then it alone is enough to cause surges in the power grid. This happens in devices that are not equipped with various circuits or power regulators (or when they fail). This happens only periodically, when such a product (for example, an oven) is connected to the network, which is why it is often called the “flickering effect” or “floating” fault.
In addition, there are a number of other reasons that are not systematic (let alone permanent) in nature - welding work near the house (at the entrance), turning on a powerful heater in an adjacent area, a lightning strike, some kind of natural disaster, and so on.
What to do
In the house
- Power up powerful household. devices (the latter are required for PCs). Each product has its own individual device. This primarily applies to those that are used intensively or continuously for a long time. For example, heating boilers, dishwashers.
- Install protective devices on the line - AB, RCD or differential circuit breakers. As a rule, they are placed in apartment (entrance) panels. There are other product options - surge protectors, special switching (protective) units.
- Check all devices for correct operation. This is not difficult to do; you just need to alternately supply mains power to them and record voltage drops (if any). The simplest indicator can be a regular Ilyich light bulb, so when testing the equipment you should turn on the light in the room.
- Carefully inspect the power cabinet in the entrance. If one of the neighbors did work in it (this is noticeable at least from the new wires) - there is already a topic for conversation. Perhaps the cause of the jumps that appear is incorrect or poor-quality installation of a section of the circuit.
Outside the home
Check whether any construction (repair) work is being carried out in adjacent areas. Voltage surges can be caused not only by turning on the welding machine, but also by the operation of powerful installations - pumps, concrete mixers, and the like. If so, then changes in the nominal value in the network are a temporary phenomenon, and power engineers do not bear responsibility for this. This means that it is useless to make claims against them.
After inspecting the area (if no obvious reasons are identified), you should contact your management company (DEZ, Housing Office, Homeowners Association) with a request to send an electrician. The goal is to measure the voltage at the entrance to the apartment and find out whether the quality of the service provided meets regulatory requirements. Many articles still refer to the old GOST, although there is already a new document - No. 54149, which came into force on January 1, 2013. It describes in detail all the requirements for mains voltage and permissible deviations from the nominal (jumps).
If violations of at least one of the points are detected, the measurement results should be validated. With this document you can now go to the power engineers. Since changes in the voltage rating are caused by reasons beyond the control of the owner (that is, they are located outside his home), and the resource supplying organization does not take action, there is a reason to appeal to the law on the protection of consumer rights.
In this case, upon the provision of a service that does not meet the requirements of regulatory documents. And if, due to deficiencies in power supply, a breakdown of complex household appliances occurs, you can safely file a claim in court. But this is another topic that requires separate consideration.
By the way, one of the functions of housing inspections (which not everyone knows about) is precisely to check the quality of services provided in the housing and communal services sector. Before suing, you can write a statement to this organization.
Not many of us know that the service life of household appliances in the house depends not only on the quality of the devices, but also on the stability of the electrical network. If the voltage level is unstable and surges occur frequently, then the consequences for equipment can be dire, and surges are dangerous not only for equipment, but also for the person who uses electrical appliances.
Power surges: why they occur
In general, to put it simply, surges in the electrical network occur when it is overloaded. The network cannot cope with the voltage and begins to work incorrectly. If the surge in electricity is insignificant, then electrical appliances as a whole will not feel it. However, if the electrical failure is serious, accompanied by short circuits, it can lead to damage to the devices. As a result, the equipment burned out: TV, refrigerator, computer, and in this case, either very expensive repairs or replacement of the device will be required.
When you plug in a device, the voltage of the general network jumps a little, but this does not at all affect the overall operation of the equipment connected to the network. An even bigger jump occurs when you disconnect the device from the power supply.
But even if you and your neighbors, along with many others, turn off many devices at the same time, this is unlikely to lead to serious surges and overloads, since the network is protected in such a case. It’s a different matter for enterprises where serious equipment, which consumes the lion’s share of the total network energy, can be turned off at the same time as a result of a failure. It turns out that the amount of energy consumed is sharply reduced at one moment and does not have time to be distributed evenly, the voltage has nowhere to go and it goes to devices that are connected to the network. In other words, the electricity that was supplied to enterprises does not dissipate without a trace after a shutdown, but is distributed for some time, causing large overloads.
Why the voltage in the electrical network jumps: reasons
If you have, for example, a computer connected to the network, then the surge will lead to the fact that not 220 V will enter the device, but much more - the equipment will burn out. Sometimes in this case it is enough to replace the power supply, in others the motherboard or processor may burn out, then the repair will cost almost as much as the computer itself.
Protecting electrical appliances in an apartment or on the territory of a private house is possible, and it is best to worry about possible surges in advance before anything burns out.
The great danger of spikes is that they are very difficult to detect. If this is a big jump that knocked out all the equipment in the house, then of course you will notice it. However, if these are minor surges, then they will remain undetected, while their regular occurrence significantly reduces the life of electrical appliances. Regular jumps can “kill” equipment slowly, even if you don’t realize it.
In general, according to the standards, the voltage in the network should be 220 V and deviate up and down by only 10%, while in practice it can drop to 180 V or less, or, on the contrary, rise to 270 V or more. An increase in voltage is much more dangerous for electrical appliances, but some of them can fail even with a sharp decrease.
Where to complain: power surges
Of course, if your equipment burns out due to network failures, then someone must be to blame. The voltage is jumping, the power level is unstable, why should you just put up with it? If your expensive equipment burned out due to faults on the line, then you need to contact the responsible authorities for investigations.
It is best to draw up a collective appeal from the residents of the entrance or several affected apartments to the management company with a demand to compensate for the damage.
In general, if the grounding cable breaks in the transformer serving the house, then a voltage of up to 380 V can be sent to the apartment. Of course, such a current will destroy all devices connected to the network. In this case, the chances of receiving compensation are quite high. However, for example, if a network failure occurred not due to the fault of the utilities and equipment serving the house, but, for example, due to a thunderstorm, then you may receive a counterclaim and it will be impossible to prove anyone’s guilt.
Power surges: what to do to protect yourself
First of all, you must remember that using appliances in your home during a thunderstorm is very dangerous. It is during a thunderstorm that serious accidents occur in the network and voltage arises that can damage equipment.
Therefore, if you have devices plugged in during a thunderstorm, first turn off:
- Fridge;
- Computer;
- TV;
- Washing machine;
- Microwave oven.
As for the daily use of technology in familiar conditions, there are several ways to protect it.
In general, all such methods involve the use of additional equipment that “takes the hit” in case of failures, this can be:
- Surge Protectors;
As for the voltage relay, this is a special device, similar to a tee, through which you simply connect the plug of the device to the socket. This primitive device passes all the current through itself and, in the event of surges, will simply disconnect the device from the network, preventing too much voltage from entering the device. Typically the relay has a display that shows the current voltage level.
The second device is a voltage stabilizer, this is already a full-fledged technique that passes all the current through itself and in the event of small fluctuations does not turn off the device, but corrects the power by directing the required voltage to the device. As a result, even with small fluctuations, you will not even detect any failures; all equipment will work as it did.
A UPS or uninterruptible power supply is an excellent device for a computer; it not only protects equipment from overloads, but also in the event of a power outage, it can power the device for some time, so you can safely turn off the device and save all current work on the computer.
Why a power surge is dangerous (video)
Power surges in the network are a massive phenomenon and they occur due to overloads on the lines. You can protect equipment from surges thanks to special voltage stabilizers, and if your devices burn out due to surges, then you have every reason to demand compensation from the management company. The most difficult thing when claiming compensation for damage is to prove guilt, since sometimes failures occur due to weather conditions or the general congestion of the network by consumers.
Changes (jumps) in network voltage have existed for a long time, but recently this problem has become increasingly relevant for our country. This is due to the constant increase in electricity consumption.
If until the 90s all household appliances consisted of a TV, refrigerator and tape recorder, now every apartment has a lot of powerful and at the same time sensitive household appliances (computers, air conditioners, freezers, microwave ovens, washing machines, video and audio equipment, etc.). etc.), which is connected to the network almost all the time.
The result of a voltage drop in the electrical network may be the failure of part of the household appliances installed in the apartment and connected to the network at that moment. In the vast majority of cases, the cause of failure of household appliances is overvoltage in the network.
After consumers' household appliances burn out, people begin to ask questions: How could this happen? What is the reason? How to avoid? And perhaps the main question is Who is to blame?
Why do network surges occur?
There are several reasons. Let's highlight the most common ones:
1 . Let's start with the fact that not only you alone (your apartment or house) are connected to the AC power network, but many consumers like you, which is important, and many more industrial and construction sites. It would seem, what impact can one house have on the power grid? Definitely a minor impact.
And if at the same time a thousand consumers turn off their equipment, especially high-power ones (electric kettles, water heaters, microwave ovens, air conditioners, washing machines), then we get some kind of overvoltage, you all noticed voltage drops in the evenings, this is noticeable in incandescent lamps.
But don’t be alarmed, it will still be less than the permissible GOST and all your equipment will continue to operate normally.
Another thing is that if an entire plant or construction site turns its equipment on/off at the same time. Imagine what a “spike” of voltage will happen!
This option is possible in areas where the infrastructure is associated with a large plant or large construction. Then it is possible that your equipment will fail.
2 . The most common reason for the residential sector - These are breaks in the neutral wire.
You all know the deplorable state of electrical transformer substations, building input devices and floor electrical switchboards at entrances, most often due to the lack of a service electrician or his illiteracy.
Periodically, it is necessary to carry out preventive repairs in electrical switchboards, which in principle is not done, therefore, over time, the bolted connections weaken, the reliability of the electrical contact deteriorates, which can lead to burnout of the supply wires.
Much more often the neutral wire (blue) burns out, which leads to the appearance in your socket group of voltage above the permissible level due to uneven electricity consumption.
The figure shows that during normal operation, the voltage between any phase wire (red) and zero (blue) is always approximately 220 volts, the current flows from phase to zero, and the voltage between phase wires is 380 volts. At the moment the neutral wire breaks, the current will flow between the phases, i.e. in the sockets there will be an overvoltage of up to 380 volts, it depends on the power of the electrical appliances connected at that moment.
For example, an electric kettle is turned on in one phase, a light bulb in another phase, and a TV in the third phase, when the neutral wire disappears (burns out), the voltage between the phases 380 Volt ends up on your household appliances. The power that the electric kettle consumes will pass through the lamp and the TV, the lamp will dry out brightly, and the TV will probably smoke.
3 . The reason is purely human factor, more precisely, the illiteracy of an electrician or the self-confidence of a home handyman.
The lights went out at home, one of the most common reasons phase wire burnout(L1, L2, L3) or zero working conductor(N), you yourself or by calling an electrician restore the power supply; when connecting, you mixed up the wires, connecting instead of 220V (phase-zero), the voltage is 380V (two phases), perhaps not even for yourself, but for your neighbors on the floor.
Result, instant failure of all electrical equipment connected to the mains.
4 . Voltage surges caused by lightning discharges near power transmission lines (PTLs) occur in areas where overhead power transmission lines are used.
5
. Another reason for voltage drops (spikes) is theft of a grounding conductor (grounding) in electrical risers of floor boards, entrance of a residential apartment building. I've been encountering this quite often lately.
As I hope you know, grounding is needed to protect against electric shock when the insulation of electrical equipment breaks down, and, in principle, everything will work without it.
What “advanced” collectors of non-ferrous metals sometimes use is to cut out the grounding from the cable riser of the entrance; this is done very quickly, literally in a few seconds on each floor of the house.
Someone will say what does overvoltage have to do with it. But the fact is that when connecting apartments, three wires are used, phase, neutral and grounding, the last two (zero and grounding) are sometimes confused with each other, so it turns out that when the grounding is stolen, if at least two apartments on the floor were connected to it , both apartments come with two different phases, between which 380 Volt.
The harm of low mains voltage
A situation is possible when the voltage in the network is greatly underestimated. This is often found in old buildings due to the inability of old wires to produce the required power, as well as the switching by utility services of all apartments of the riser to the same phase, for fear of burning out the neutral working conductor, which would lead to overvoltage in the network. Low mains voltage can damage some household appliances or their functions, for example, a microwave oven spins the plate but does not heat; the washing machine works without stopping; The most common breakdown is the failure of the refrigerator compressor, due to the constant on position, even when you are not at home.
Equipment damage from undervoltage is less common than from overvoltage. You can also avoid equipment failure by also using the points from the section “How to deal with network overvoltage”
And so we looked at the main causes of voltage drops in the electrical network, but this does not make it any easier because the equipment has already burned out, then read on.
Who is responsible for lost household appliances?
Paradoxically, despite the fact that the electricity supplier undertakes to provide you with voltage of the established quality, most likely you will not be able to receive compensation for the lost equipment.
This is due to the following considerations.
How can you prove that the cause of equipment failure is an overvoltage in the network, and not a defect in the equipment.
The lack of real control and collection of statistics leads us to the following conclusion. In 99% of cases, you will not be able to receive compensation for lost equipment because... it is impossible to prove whose fault it is, as we said earlier, there are many causes of overvoltage, both related to human factors and force majeure by definition (lightning strike near power lines).
What to do, really throw out the equipment every time? Of course not. There are methods to combat voltage surges in the electrical network.
How to deal with network surges
There are several ways:
1 . Reconstruction of electrical networks and maintenance by competent electrical personnel, a very expensive option and only reducing the risk of overvoltage, most often depends on utility services
2 . The use of voltage stabilizers is an ideal option for those who use very expensive equipment. You connect the network wires to the stabilizer and remove high-quality voltage from it. The option is very good - there is only one drawback - the price. The price for a good (high-quality) stabilizer with a power of 5 kW is over 30,000 tenge.
Accordingly, if you have a large amount of equipment you will have to spend a tidy sum, but after that (if you choose the right stabilizer) you can rest assured that your equipment is reliably protected.
3 . If you work with valuable information on a computer, then choose an uninterruptible power supply (UPS), which is most often used in administrative buildings, but only for office equipment; you cannot install an “uninterruptible power supply” on all household appliances due to the high price and high operating costs. expenses.
4 . A voltage relay is the most affordable option for protection against voltage surges in household and office electrical networks.
In Kazakhstan there are the following devices:
Single-phase voltage relay RN-113
Single-phase voltage relay RN-111M
Conclusion
In this article, I expressed only my view on the existing problem of voltage drops in household and industrial networks. I do not claim to have the absolute truth on all points. It is worth considering that the methods of struggle are valid at the time of writing.