How to protect an apartment from power surges. Protection of household electrical appliances from power surges. Resanta is a fairly well-known Chinese manufacturer on the Russian market. It produces a lot of things, including such voltage relays

Modern life leads to the appearance of more and more complex household appliances, equipment and electronics in our homes and apartments. At the same time, the quality of power supply wants to be the best for various reasons. On the other hand, the industry offers a whole range of electrical devices that allow you to solve these problems yourself in your own home. Let's get acquainted with them and make our choice.

Voltage level control in the network

Types of voltage surges in the power supply network

It is difficult to choose the right surge protection system without knowing its nature and nature. Moreover, all of them are of a natural or man-made nature:

1. Often the voltage in the network becomes stably low. The reason is an overload of an outdated power transmission line (PTL), for example, as a result of the massive connection of electric heaters or air conditioners in the corresponding season.
2. Under these same conditions, the voltage may be too high for a long time under insufficient load.
3. A situation is possible when, with a stable overall power level, pulses and high voltage surges appear in the power supply line. The reason may be the operation of a welding machine, a powerful power tool, technological equipment, or poor-quality contact in power lines.
4. A rather unpleasant surprise is a break in the neutral wire in the 380 V network of the supply substation. As a result of different loads on the three phases, a voltage imbalance occurs, that is, on your line it will be too low or too high.
5. A lightning strike on a power line causes a huge surge in overvoltage, which leads to the failure of both household appliances and internal wiring of buildings, which leads to a fire.

How do plugs and vending machines protect household appliances?

For a long time, in our houses and apartments, fuses called plugs remained a universal means of defense against the troubles listed above. They were replaced by modern circuit breakers (circuit breakers), and reckless people stopped installing bugs, restoring burnt-out plugs. Today, in many apartments, circuit breakers remain practically the only means of protection against problems in the home electrical network.

Circuit breakers are replacing fuses

During operation, a circuit breaker trips when the current flowing through it exceeds the value indicated on its body. This helps protect electrical wiring from overheating, short circuits and fire in case of overload. In this case, the overvoltage manages to damage the electronics, and with a short surge the machine will not even work.

Thus, a powerful impulse caused by a lightning strike passes through the circuit breaker and can puncture the wiring with the listed consequences.

In other words, the machine does not save you from increased voltage and its surges or drops.

Why is a surge protector connected to a home network?

SPDs (surge protection devices) have been developed specifically to organize a protection system against lightning strikes and the resulting overvoltage pulses. Note that power lines have certain means of compensating for lightning strikes. Also in the power supplies of modern electronic devices there are SPDs of class III.

Modular surge protectors for installation in an electrical panel

However, this is not enough if you live in a private house powered by an overhead power line. The method for selecting and connecting an SPD is given in the article. In any case, a lightning rod, which is described in the article “

RCD functions in the power supply scheme at home

The power supply circuit of a modern home necessarily contains an RCD - a residual current device. Its main purpose is to protect people from electric shock, as well as to protect electrical wiring from breakdown and leakage, which can lead to a fire. The method for selecting and connecting an RCD is given in a special article.

Single-phase and three-phase RCD

Undoubtedly, if your home has not yet installed an RCD, this must be done. At the same time, the protective shutdown device saves from voltage surges only to some extent and indirectly.

Protecting electrical appliances with a voltage stabilizer

An electrical stabilizer is a device that maintains a stable voltage at the output when it changes at the input within acceptable limits. The device can have different power and provide stable power supply to the entire house or individual consumers.

Voltage stabilizers of various capacities

The stabilizer does an excellent job of correcting slowly changing low or high voltages. Depending on the operating principle, it compensates for sudden surges or surges to varying degrees.

Modern units have a function to turn off the power supply when its level in the network reaches limit values. After the input voltage returns to an acceptable value, the power supply is restored.

However, the device does not protect against lightning overvoltage.

Of the devices we reviewed, the stabilizer is the most expensive. Read the article

An alternative option is a network voltage monitoring relay

A budget alternative to a stabilizer is a voltage control relay, which performs the specified function of turning off the power supply when the voltage in the network goes beyond acceptable limits. Depending on the design, the device is triggered when there is an overvoltage, or it also controls its lower level.

Modular voltage relay options

There are relay modifications that restore power automatically when it returns to acceptable limits, or this must be done manually. The most advanced devices provide the ability to set voltage levels at which consumers turn off and the delay time when power returns. For example, a refrigerator should not be plugged in again within five minutes to avoid damaging the compressor. This is the value that can be set on the relay.

The ASV-3M voltage relay must be turned on manually after activation

In this case, the relay does not provide a stable voltage, does not compensate for pulse surges and does not protect against lightning overvoltage. In other words, this method of protection is suitable in a situation where the voltage in the network is normal, but rare and significant deviations are possible, including as a result of an accident in the power supply network.

Voltage relay for low-power consumers

There are options for protecting individual consumers in the form of an extension cord or a monoblock with a plug and socket. These devices are designed for a load current of 6-16A. Similar devices in modular design are mounted on the electrical panel.

A modular type relay can have a switching group of contacts, normally open contacts, as well as two separate groups of normally open or normally closed contacts at the output. This allows you to implement different options for managing consumer power.

Wiring diagram for connecting a voltage relay in a 220V network

The wiring of a modular type voltage relay can be done according to the above illustration. In any case, the device is connected after the input machine. The neutral wire is connected to terminal N, and the phase wires are connected to the normally open contacts of the relay.

To protect a more expensive device, its rated operating current is selected one step higher than the value indicated on the body of the input circuit breaker. For example, if a 40A circuit breaker is installed in front of the relay, choose a device with a rated value of 50A.

If a device with the required operating current is not available or is too expensive, it can be replaced with a voltage relay with a minimum load parameter. In this case, a contactor of the required power or a starter is connected to its output, which supplies voltage to consumers.

Voltage relay connection diagram using a contactor

The wiring of the voltage relay paired with the contactor is shown in the diagram. In this example, the voltage relay itself is also connected after the input circuit breaker, meter and RCD. The phase wire from the output contact of the relay is connected to the terminal of the control winding of the contactor, and the neutral wire (the protruding part of the housing) is connected to its second terminal. The power phase and zero are supplied to the output terminals of the contactor (the far part of the housing) from above, and the phase and zero wires of consumers are connected from below.

If there is a normal voltage level in the network, the control relay closes the output contacts and supplies power to the contactor winding. He, in turn, closes the output contacts and supplies power to consumers. If there is no voltage in the network or it goes beyond the permissible limits, the circuits are sequentially broken and the power to the load is turned off.

Connection diagram for several voltage relays in a single-phase network

In some cases, it is convenient to use several voltage relays for different types of consumers. At the same time, for the most expensive electronic consumers, such as computers, you can set the permissible input power range within 200-230V using the appropriate relay.

Household electrical appliances with electric motors, such as a refrigerator or washing machine, can be set to a voltage range of 185-235V. Consumers such as an iron, heater or water heater can be powered by a voltage of 175-245V. The relay's internal timers can be configured to delay power restoration at different times.

How does a phase control relay work in a 380V network?

A three-phase voltage relay can be installed in a 380V network. This makes sense if the house has equipment with three-phase power.

Connecting a voltage relay to a 380V network

In this case, the relay is triggered when there is a voltage deviation in any phase and turns off the load along all three lines. In the absence of consumers with 380V power supply, it is more convenient and cheaper to connect three separate voltage relays. In this case, we get three groups of 220V consumers, for which different voltage limits and delay times can be set.

Connection diagram for a voltage relay on each phase in a 380V network

What does IPB protect against?

The main task of an uninterruptible power supply (UPS) is to provide consumers with electricity when there is no voltage in the network. Most often this device is used to power computers. Although the UPS provides 220 volts for a short time, it is possible to save the information and turn off the computer. It is relevant to use an uninterruptible power supply when using a small-sized power plant for continuous supply of energy at the time of its startup.

Common uninterruptible power supply

Obviously, the use of UPS is functional if a voltage relay is installed in the home's power supply network. When using a battery of sufficient capacity, a gas boiler can be connected to an uninterruptible power supply. A 60Ah battery is enough to supply a 160W boiler with voltage for about a day.

A double conversion UPS operates over a wide range of input voltage variations, but is very expensive.

Probably, in most cases, for domestic purposes it is more practical to use both an inexpensive uninterruptible power supply and a voltage stabilizer or relay.

How a surge protector can help

Most often, household surge protectors are made in the form of an extension cord. Thus, several units of household appliances can be connected to it at once. Filters differ in the number of sockets and cable length. Typically the device is equipped with its own switch indicating power supply. The filter may have individual power switches for each outlet.

Popular network filters

A number of models have short circuit and overload protection. The total load current of devices of this kind does not exceed 6-16A. The actual filter of such devices consists of several capacitors and inductors. This protects the electronics from low-power and short-duration interference pulses. The latter can be created, among other things, by household appliances connected to the home network.

Good afternoon. In my old apartment/country house, I recently had a power surge at the main switchboard. All the equipment in the apartment burned down. Thank God, so do the neighbors.

This dialogue with various variations is heard quite often in the office of our company. To prevent you from saying it one day, we suggest you familiarize yourself with some typical surge protection devices that can be used to protect against voltage surges

1. Surge suppressors - UZIP- are designed to protect equipment from surge surges that may occur, for example, due to a nearby lightning strike on a power line or the close operation of devices with high inductance.

Mainly used in suburban housing.

Operating principle: During an overvoltage pulse, SPDs increase their resistance and short-circuit the discharge propagating through the system to ground.

2.Voltage relay-used to protect equipment from power surges or “zero break”

It is used in both urban and suburban housing.

The principle of operation is that the relay breaks the circuit when voltage deviations in the network are greater than the specified values. After the network voltage is restored, the device automatically closes the circuit. .

The most famous devices on the Russian market. Installed when

Relay RN 113

Maximum current -32A

Voltage regulation Umin 170-230 Umax 240-290

Availability of a display showing the current voltage in the network.

Installed in residential distribution boards in single-phase networks. If an apartment or house is tangled using a three-phase network, then each phase is usually protected

Relay 101M

Rated current 16A,

Voltage regulation Umin 160-220 Umax 230-280

Installed by plugging into an electrical outlet, the protected equipment is connected directly to the PH 101M.

Availability of an LCD screen with indication of the current network voltage

Our company is a dealer of the Novatek Electro company, so we preferably recommend the use of the RN 113 relay to our clients.

Relay UZM 51

Load protection from surges in mains voltage

Max. pulse shunting current with varistor - 8000 A

Provides suppression of pulses with energy up to 200 J

Load protection from high voltage (more than 270 V, for UZM-51 242-286 V)

Load protection from low voltage (less than 170 V, for UZM-51 154-198 V)

Fixed response delay - 0.2s when voltage is exceeded

Voltage relay RN-106 Novatek Electro (analogous to UZM51)

Protection of outgoing lines from over/under voltage (in the range of 160-280V) and neutral breakage

Rated current - 63A

Power of connected electrical appliances - up to 14 kW

3.Phase switch PEF 3

used to increase the uninterruptibility of power supply to single-phase loads from a three-phase network.

When the voltage in the supply “phase” changes, the relay will switch the power to another phase in which the voltage corresponds to the specified values.

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!

In this article, we will analyze in detail, how to protect yourself from power surges and surges in the household electrical network.

Voltage surges are especially relevant for old housing stock, where the electrical wiring is already old, in some places completely dilapidated, connections are loose, and the neutral wire often burns out. And this, in turn, leads to the fact that in some apartments the voltage drops below the permissible level, while in others, on the contrary, it increases abruptly and can reach almost 380V.

A sharp increase in voltage leads to the fact that household appliances simply burn out and fail. And reducing the voltage below the permissible level is especially dangerous for household appliances, which include electric motors: refrigerators, air conditioners, washing machines, etc. The reduced voltage leads to an increase in starting currents in electric motors, which can ultimately lead to damage and failure of their windings .

In order to protect electrical wiring and devices connected to it, special devices are used - voltage control relay. They are also called overvoltage relays, as well as maximum and minimum voltage relays, or simply “barriers”.

Let's take a closer look at the operating principle and connection diagrams of these devices using the DigiTOP voltage relay as an example.

I will not go into detail about the technical characteristics; if necessary, you can find it on the Internet. I will briefly note the most important thing.

The relay circuitry measures the effective voltage value and when the upper setting is exceeded, or when the voltage becomes less than the lower setting, the relay opens its power contact, turning off the phase, thereby disconnecting the external power supply from the internal wiring.

The left down arrow button adjusts the lower voltage threshold (default 170V). The right up arrow button adjusts the upper voltage threshold (default 250V).

By pressing both buttons at the same time, you can adjust the delay time when the relay is re-energized when the voltage returns to the operating range.

In single-phase 220V networks, two main schemes for connecting voltage relays are used:

—in the first circuit, the relay contacts directly control the load, i.e. all the current consumed by electrical appliances connected to the home network flows through them;

— in the second scheme, the relay contacts control the contactor winding, and the load is already connected to the network through the power contacts, thereby relieving the contacts and increasing the reliability of its operation.

The circuit with the contactor is discussed in detail in the video at the bottom of this article!!!

We will consider the first scheme.

The voltage relay is installed after the meter, usually in. The phase wire from the external power supply (after the meter) is connected to the terminal 2 power contact of the voltage relay. Further through the power contact from the terminal 3 phase is supplied to the home electrical wiring network. Zero is supplied to the terminal 1 in order to power the circuitry of the relay itself. Those. the zero is not broken, the relay contacts control only the phase wire.

When the input circuit breaker is turned on, power is supplied to the voltage relay. If the voltage value is in the operating range, then after a delay time (set using the buttons on the front panel), the relay contacts close and the phase is supplied to the internal electrical network and it is ready for operation and connecting consumers.

Let's assume that there was a voltage surge and its value exceeded the upper threshold of 250V. The relay monitors this change and, when the upper limit is exceeded, opens its power contact, thereby breaking the phase wire and stopping the supply of power from the external electrical network to the internal network of the apartment or house.

This allows you to protect connected household appliances and other electrical appliances from failure.

When the supply voltage returns to the operating range again, i.e. becomes less than 250V, the voltage control relay, having withstood the set time delay, will again close its power contact and the circuit will return to operating condition.

In a similar way, protection against unacceptable voltage drop occurs.

Since in this circuit for connecting a voltage relay the load is connected directly through its power contact, when choosing a relay it is necessary to choose a model designed for a current greater than the current of the input circuit breaker. This will provide the necessary margin and protect the relay circuitry in the event of switching the maximum load. We do the same for .

Connection diagrams and operating principles of voltage control relays.

I recommend materials

Voltage surges and surges in our electrical networks are, unfortunately, not uncommon. At enterprises, special devices are installed to protect against such surprises, but there are none in the distribution boards of residential apartments and houses. And it is not the responsibility of housing and communal services to install such devices.

What are the dangers of “mood swings” online?

• Loss of data in computers due to electronics failure.
• Home appliances burn out.
• Ignition of electrical wiring and, as a result, fire.

According to Russian GOST, the permissible voltage deviation must be within ±10% of the nominal voltage, i.e. in a regular household outlet it should be from 198 to 242 Volts. During surges, the voltage in the network can fluctuate from 35 to 400 volts and higher.

You need to know that not only an excessive increase in voltage is dangerous, but also a significant decrease in it.

With increased voltage (surges), power supplies, especially imported equipment, either immediately burn out from overload or reduce their service life for years.

Low voltage (sag) is less dangerous, however, it can also lead to failure, for example, of a refrigerator compressor, household appliance power supply, etc.

There are several reasons for voltage surges:

• Lightning discharges (lightning) near power lines. Therefore, during a thunderstorm, it is imperative to unplug all household appliances.
• Accidents at high-voltage networks and substations, when high voltage (6 or 10 thousand volts) reaches the low voltage side.
• A break (burnout) of the neutral wire in an electrical cabinet or at a substation is the most common reason. The wire can burn out if it is not securely or incorrectly connected. If it breaks (burns out), a so-called “phase imbalance” occurs, when in some apartments the voltage rises to 380 V and higher, while in others it drops to 25-40 V.

To protect household appliances from premature destruction, and the house from fire, it is necessary to purchase and install special protection devices.

Yes, these are additional expenses, but they are worth it. After all, even if it is possible to repair a broken computer, refrigerator, TV or washing machine, the victims will still face headaches, loss of time and financial expenses.

Currently, there are a lot of technical devices for protection against voltage surges. And not all of them are equal, both in price and quality. In addition, unfortunately, there is no single state standard for protective devices of this class yet. That is, there are no standards establishing at what voltage value the load should be turned off, what the time delay should be, etc. Due to the lack of a general standard, certification of such devices occurs under technical conditions determined by the manufacturers themselves and at their expense. And this makes it difficult to compare similar devices with each other.

Let's look at the most proven and common surge protection devices.

This is the most affordable protection option, but only for one separately located electrical appliance. Popularly, this device acquired the name “pilot”, thanks to the brand name of one of the surge protectors.

A surge protector protects only low-power equipment (computer, audio or video system) and only from small voltage surges. It will not save you from significant throws; at best, it will burn itself out.

Or rather, the varistor built into it will burn out - an electronic element that, during a short-term voltage surge, dissipates the energy of the surge in the form of heat.

The second important element of a surge protector is the rejector. It protects against high-frequency interference generated by running electric motors, generators and welding machines near your home.

The third element - a fuse (fuse) - protects against short circuits.

But all these elements are built only into real surge protectors, and not into “extension cords”, which do not have any protective elements, but which they will happily sell to you if you don’t know the difference. Therefore, in order not to make a mistake, before purchasing you should study the technical data sheet - all the protective systems of a particular model should be indicated there.

For any, even the most expensive, surge protector, it is necessary to have a high-quality, well-made grounding.

Because the filter drops all impulse noise and overvoltage to the ground through the grounding conductor.

Without a physical ground, the filter turns into a regular extension cord.

This is an ideal option for those who use expensive equipment. Unlike network filters and UPSs, if the voltage in the network fluctuates within acceptable limits, the stabilizer does not turn off the power supply, but normalizes the voltage to exactly 220 V. But if the voltage rises to 250 V or more, it will cut off the power supply from the network. After the operation of the electrical network is normalized, the stabilizer will automatically connect the power.

The stabilizer can be installed either on a separate large power receiver or on the entire home network. In the second case, you need to sum up the power consumption of all electrical equipment in the house and, based on this power, select a stabilizer.

4. Voltage control relay (VCR)

The most advanced devices on the list, designed specifically for protection against voltage surges. And not only from high, but also from low. These craftsmen independently turn on the power supply after the network voltage returns to normal, with a short delay.

They look like 2-3 ordinary modern modular machines connected together. And they are also installed in panels on a DIN rail.

Of the fairly large number of ILVs offered on the market, the most tested and in demand are AZM-40 (automatic protective module) of RESANTA LLC and UZM-50 (multifunctional protection device) of MEANDR CJSC.

The operating principle of both products is based on comparing the mains voltage with reference values ​​using an analog control device.

Protection of apartments and offices from high voltage UZM-50, UZM-51

• Rated switching current 63 A
• Maximum switching current 80 A (for 30 minutes)
• Setting the upper response threshold from 230 V to 280 V in 5V steps
• Setting the lower response threshold from 210 to 160 V in 5V steps
• Two-threshold overvoltage protection /(delay) > 230...280 V /(0.2 s) > 300V /(20 ms)
• Two-threshold undervoltage protection / (delayed response)< 210...160 В/ (10 с) < 130В /(100 мс)

Multifunctional protection device UZM-51, UZM-50 protection of equipment (electrical equipment of an apartment, office, etc.) when the mains voltage goes beyond the permissible limits of single-phase networks. After power supply or after an emergency shutdown, switching on occurs automatically when the mains voltage is restored to normal.

ZUBR D340t Improved model of voltage relay with thermal protection.

• Built-in protection against internal overheating
• Possibility of adjusting voltage indication
• Shutdown time when exceeded no more than 0.05 s
• Shutdown time when decreasing no more than 1.10 s
• Maximum load current 40 A
• Maximum load power 7.2 kW
• Supply voltage 100-400 V
• Main dimensions 80 × 90 × 54 mm
• Display correction ±20 V

Voltage relay ZUBR R216y is a successful model of voltage control relay for use in the kitchen. For example, you can protect a refrigerator and a TV at the same time. The grounding contact of the socket and plug of the device provides additional safety by protecting against electric shock. Complies with all standards for the operation of household equipment.

• Domestic standard plugs and sockets Availability of grounding contact
• Adjustable upper voltage limit 210-270V
• Adjustable lower voltage limit 120-200V
• Off time when exceeded no more than 0.05 s
• Off time when decreasing no more than 1.20 s
• Maximum load current 16 A
• Maximum load power 3 kW
• Supply voltage 100-400 V
• Fully assembled weight 0.12 kg
• Main dimensions 42 × 53 × 143 mm
• Turn-on delay time 3-600 s