Which Uzo to choose. Why is the UDO at entering a private house? What a protective shutdown device to select

The choice of the UDO (protective shutdown device) is a non-trivial task requiring a person of some immersion in the field of knowledge of electrical installation and the principles of electrical equipment. Many, frightening possible mistakes in the calculations, shift this duty on a professional electrician, but such a service is worth money. In addition, you can not always be sure that a third-party person will make the optimal choice in the price value and the required characteristics. Therefore, it is useful to know how to choose a Uzo for a home or apartment yourself, especially since everyone can cope with it.

Varieties of devices

The principle of action of the protective shutdown devices fully corresponds to their definition - when the network that feeds through this device occurs, current leakage occurs or a short circuit, the machine immediately opens the circuit inside itself, stopping the current. This avoids the occurrence of fires, shocks of people from the body of electrical technology and other consequences of varying degrees of severity. The system works so quickly that a person who touched the case under voltage will not even have time to take a blow (if the RCD is adjusted for instant response). Similar actions occur when closing or limiting wiring temperature.

Uzo disassembled

Before you choose the UZO, you should know that these devices are divided by the type of leakage current into two categories:

• AC is simple UzOs that react to changes in the parameters in the AC circuit section. Frequently used to protect household appliances of small power or branches of the apartment.
• A - more advanced devices working with leaks not only alternating, but also straightened pulsating DC. Modern apartments are needed to protect washing machines, electric stoves, boilers and other powerful devices.

The second type UDO has a more complex design, therefore, is expensive when buying. In addition to the data of the two types, there are still several less frequently used devices:

• B - Machines for working with constant and alternating currents intended for use in industrial and industrial facilities;
• S is a protective shutdown device with a given time setting on shutdown. The main purpose is to prevent fire due to cable ignition. For this reason, s Uzo are installed in the distribution shield of the apartment, to protect the entire wiring.
• G - automata for fire protection of individual devices, which is usually less reaction delay.

Select the device by network parameters

Perhaps this is the most important section in the article. It is he who will help competently choose protective equipment.

Selection of a protective shutdown device must be carried out in accordance with the operating parameters of the network in which it will be built in, for example, by power. During repair, this work falls on the electrician, which can correctly enroll the wiring, installing individual branches for powerful electrical equipment. However, in a situation where the repair is performed independently or laying a separate posting line arises due to the purchase of a washing, dishwasher or boiler, you will have to pick up the UDO.

The main operating parameters of the UZO is the nominal disconnecting differential current and the rated current of the load. The first value should be no higher than not a third, relative to the sum of the leakage currents of all devices connected and connected during the operation of the instrument network. Such a feature is due to the fact that the machine works in a rather wide range: 50-100% of the rated current. This is necessary for the reason that the connection to the network is any network can "overlap" 17% (third of 50%) of the differential current and the RCD will stop the power.

If the ability to determine the amount of leakage currents is not possible, an approximate calculation is used, in which the load leakage current is taken to be 0.4 mA per 1A power consumed, and the current leakage current is 10 μA per 1 m phase vein.

Payment

An example of the calculation for the electric stove from the value of the power consumption of 5 kW and the wire laying distance to the distribution panel is 11 meters. Based on the conditional data presented above, the calculated leakage current is 11 mA. The approximate consumption of the electric stove at full power is 22.7 A, and the calculated leakage current is 9.1 mA. The sum, respectively, is 9.21 mA. To protect against leakage currents, in this case, it is proposed to use the device with the nearest value of the diop rating. Current, that is, the RCD is 30 mA.

After that, it is necessary to determine the value of the rated current of the RCO. To do this, take the maximum consumption current and select the appropriate protective device. In the example, this maximum is 22.7 A, it means that it is necessary to take the RCO on 25a or 32a. Thus, a shutdown device should be suitable for protecting the shown electrical stoves should have a rating of 25a 30ma or 32A 30mA. The Differential Machine for the protection of the UDO should have the corresponding parameters - 25a for the first and 25-32a for the second case.

Protection in apartments and houses

It should be said that the Uzo and the machine must be selected correctly so that their operating parameters allow you to turn off the current in the desired moment. In situations where the bundle of the automatic-Uzo is set to protect the wiring from the ignition, the devices are taken with a very high summary value of the leakage - from 500 mA or 300 mA. Such a back prevents constant false shutdowns, but has a certain feature.

The fact is that the consumption current of the incandescent bulb with a capacity of 60 W is no more than 0.3A - the machine does not work, because this value is lower than the nominal even in a situation where the current goes to the "Earth", and not to zero living. It turns out that protection against fire is done correctly, but contradicts the requirements of human protection from shock.

To date, certain standards are accepted on how to properly select a protective disconnection device for an apartment or a private house. To begin with, it should be said that today for both cases, it is recommended to install only AC-type protective disconnect devices that support the operation of electrical appliances with a pulsating constant current.

So, in most modern apartments, a single-phase electrical network with a variable voltage of 220V is laid. Therefore, for them to properly install the UZO and the machine with a nominal current 32 A. This indicator is optimal - the device does not work too often due to overload, ensures reliable protection of people from electric shock and does not allow the wires to light up. The machine must be shared if the total load does not exceed this indicator (taking into account all possible connections). But for washing, dishwashers and similar equipment are set separate devices.

Number of Uzo in the apartment

In the average studio apartment with a modern technical equipment (TV, microwave, computer, washing machine, iron) The following NMO will be optimal:

1. One device with a leakage current of 30 mA - to the kitchen.
2. One device with a leakage current 10 mA - on a branch that feeds the bathroom.
3. One device with a leakage current of 30 mA - on the rest of the room.

In private houses, as a rule, a three-phase high-current highway is now served, so here in the distribution panel, a four-pole Uzo should be installed and the same differential machine. Due to the presence of a large number of high-power electrical appliances, there are not one automatic in switchboards of private houses, but several on line lighting, sockets and powerful consumers. Often it turns out a cascade power scheme.

Under these conditions, it is recommended to establish a disconnection device with a leakage current not lower than 100 mA in compatibility with the type S rattomatom (selective shutdown delay). AC type AC with a par value of 30 mA in this scheme is suitable for the nutrition of individual rooms and groups of rooms.

Technical requirements and features of the selection of the UZO

1. To get rid of possible difficulties, it is desirable to choose a protective device that opens the chain not only phase conductors, but also zero. This is done so that it is not necessary to think about protecting from the superflock on the "zero".
2. The worker "zero", which is in the circuit, protected by the UZO, should not be contacted with the protective "zero", or grounded elements, it always leads to a network shutdown.
3. Regardless of the scope of use, the protective device must be calculated for possible overload in the action zone. By default, it is provided with a 30% margin in the selection of nominal values. So, with a total leak of 20 A, it will be safer to establish the RCD by 32 A, and not 25 A.
4. The protective device must continue to work with short-term voltage drops up to 50% (not more than 5 seconds) from the nominal. This is necessary for the work of the response delayed.
5. Due to the increased electrical hazard in bathrooms and bathrooms, kitchens, shower and other rooms with high humidity, it is required to install a Uzo with a current current of 10 mA if they are connected to a separate line on the camshaft. If the kitchen, the corridor and the bathroom are located on the same branch of the power grid, the rated current of the UDO must be standard - 30 mA.
6. To properly install the RCD with maintaining performance, pay attention to the technical features of the requirement. Many import models, for example, eliminate the possibility of connecting aluminum wires.
7. In the houses of the old building, where the dilapidated, often aluminum wiring was laid, with unreliable insulation, the protection of protection in the power shield has little meaning. Due to weak wiring with a multitude of leakage damage, they will occur quite often and lead to regular disabling networks. In this case, to ensure the safety of equipment and people, we need to use portable UZOs, similar to the adapter for the outlet.

Main characteristics for selecting Uzo

Consider a number of important features for the choice of the RCD. Devices are;

- for single-phase and three-phase power grids 220/380 V;
- two-pole RCD for a 220 V network and four-pole for 380 V;
- the value of the rated current of the UZO for different loads is 10, 16, 25, 32, 40, 63, 80. 100 A;
- the size of the differential current or current of leakage of the differential switch to 6, 10, 30, 100, 300 and 500 mA;

Two-pole and four-pole

Type of differential current;

- and for alternating current;
- AC The ability to work the RCD on the variable and non-straightened constant current;
- in for the operation of protection on alternating and constant current;
- s work UDO with time delay;
- G Work with a time delay less than S. type devices

Also, the protective shutdown device has the same characteristics as the machine.

1. "Inc" The short circuit current value when the device is turned off, shows reliability and short-circuit resistance.
2. "IM" switching capacity of the trouble-free operation of the contact group.

The values \u200b\u200bof 1000-5,000 A. are considered good indicators.

How to choose the right ed

The differential device can be electronic or electromechanical execution. The electromechanical version has a differential toroidal type transformer and an executive unit in the form of a polarized relay. Electronic differential devices have an electronic board running from the network voltage.

Since the electrical network, we have not reached a good quality (voltage jump, frequent shutdown, lowered or overestimated voltage), the electronic device of the device may refuse. The recommended option is a more reliable electromechanical device, the power source is not used for it.

When choosing a RCO, it is also important to consider leakage currents in the electrical instruments themselves. All electrical appliances have their current leaks, the magnitude of which depends on their quality of execution. The leakage current value is usually indicated in the characteristics of the device. These values \u200b\u200bshould not exceed 30% of the values \u200b\u200bof the leakage of the protective shutdown. For example, for a leakage current of 30 mA, the current leakage of electrical appliances should not be more than 10 mA.

When choosing differential protection, it must be considered, otherwise there will be frequent false network disconnects. The voltage of the electrical network we have the form of sinusoids, so the protective switch is selected the appearance of the AC or A for alternating voltage.

How to choose an apartment for apartments

Before installing protection in the apartment, the rated current of the introductory automaton is calculated and after the bipolar protection with the rated current is selected by an order of magnitude or two above the current of the input machine. Suppose the introductory machine you have 25 A, then a rated current of protection is selected 32 A.

Basic parameters on the EMP housing to select

Less than 30 mA device of the device should not be chosen, since the amount of leaks of all consumers can be sufficiently high and the protection will give false responses.

How to choose a Uzo in a private house

Connecting a three-phase network at home, set four-pole differential protection. The electrical wheel is installed on the first floor, the "S" type is set with the delay time and the leakage current values \u200b\u200bof 100 mA. From the introductory machine, the lines of power grids on floors, rooms, kitchen, bathroom are bred.

For individual premises, protection should not exceed the current leakage of 30 mA. If the wiring has already served its time, then there is a possibility of frequent false response of the device. It is recommended to install the built-in socket.

The increase in the number of household appliances increases the risks of obtaining the electrician during its operation. Therefore, in the premises it is recommended to install protective systems, warning current leaks.

To ensure the stability and safety of the use of devices, it is necessary to correctly pick up and install the RCD. Before buying, it is necessary to estimate the operational features of the room, the type of electrical wiring and decide on the connection scheme of the protective device.

Doubt how to handle the task? We will tell you how to choose the Uzo, what parameters it is important to take into account to ensure the normal functioning of the technique, and how can I trust.

To prevent a random blow to a current when contact with household and industrial electrical applications was invented.

It is based on a transformer with a toroidal core, which monitors current strength on the "phase" and "zero". If its levels diverge, the relay is triggered and disabling the power contacts.

You can check the UZO by pressing a special button "Test". As a result, the current leak is simulated, and the device must turn off the power contacts.

Normally, any electrical device has a current leakage. But its level is so small that is safe for the human body.

Therefore, the RCO is programmed to trigger when the current value that can cause electric crawling to people or lead to a breakdown of technology.

For example, when the child is satisfied with the rosette of a bare metal pin, electricity leakage will occur through the body, and the RCD will turn off the light in the apartment.

The speed of the device is such that the body does not experience any negative sensations at all.

The Uzo adapter is convenient to move the possibility of quick movement between the outlets. It will suit people who do not want to engage in stationary protective devices

Depending on the power of the connected technology, the presence of intermediate protective devices and the length of the electrical wiring is used with the various limit values \u200b\u200bof differential currents.

The most common protecting devices with a threshold level of 10 mA, 30 mA and 100 mA. These devices are enough to protect most residential and office space.

It should be remembered that the classic Uzo does not protect the wiring from a short circuit and does not turn off the power contacts during network overload. Therefore, it is desirable to use these devices in a complex with other mechanisms of electrical protection, for example.

Classification of protective devices

Despite the simplicity of the internal device, the selection of models of the Uzo on the market is quite large. Each device has a specific set of technical parameters that cannot be configured during operation.

The manufacturer and sizes of the UZO do not affect the possibility of sharing within the same scheme. They can be mounted in any combination

To facilitate the choice of the Uzo, one should consider the options for the classification of these devices.

1. In speed of response The RCD mechanism is divided into ordinary and selective models. The first turns off the power contacts almost instantly, and the second - with a delay. Selective UzOs are used in multi-level systems where the sequence of response is important.
2. By type relays The UZO is divided into electromechanical, tearing contact with the mechanical manner, and electronic, preventing current supply using a semiconductor circuit.
3. By type of current. AC type AC is disconnected from AC leakage, type A - from variable and permanent.
4. According to additional features: Without protection against network overloads and with that. The RCD with a short circuit or high current response mechanism is usually called diffanttomatics.
5. By structural execution. There are UZOs attached to a DIN rail on the wall, as well as instruments in the form of a socket, a portable device, an adapter.
6. Over working voltage: for 220V, 380V, combined.
7. According to energy dependence. There are models of Uzo, capable and unable to disconnect the power load in the absence of operating voltage.
8. By the number of connected poles: Two-pole and four-pole.

For the right choice of the RCD, it is not necessary to know its technical specifications. In order for the device to effectively perform its protective function, it is necessary to take into account when purchasing the length of the domestic wiring, the power of the connected devices and some other parameters.

Rules for selecting protective devices

Before buying Uzo, you can visit the electrical forums to search for the Council on the reliability of a manufacturer.

However, select the maximum and threshold current, the number of poles, the mounting scheme and other technical parameters is necessary individually, based on the features of the room and the electrical wiring.

Power device selection

The protective shutdown device does not control the power consumption of the connected devices, but has limitations to the maximum flow of current.

Conclusions and useful video on the topic

Selecting the UDO with the consideration of options, as well as the explanations of the features of various schemes for connecting them:

Rules for the choice of UzO, part 1:

Rules of choice of UzO, part 2:

Choosing a suitable RCD, especially when installing two-level systems, it is better to entrust professionals.

It is easier to invite an experienced electrician to the house and consult him than to change the unimportant goods in the store. After all, the health and life of loved ones who will enjoy domestic electrical appliances.

Have something to complement, or have questions about choosing a protective device? You can leave comments to the publication, participate in discussions and share your own experience of the selection of the Uzo for home or apartment. The form for communication is located in the bottom block.

Step 3.
Select the rated current of the RCD.

Remember that the UZO protects the chain only from the leakage currents, and from the short circuit currents and overload currents - does not protect. Therefore, in series with the Uzo, you must install the circuit breaker.

The rated current of the UzO is selected equal to or level above the rated current of the circuit breaker, which protects this section of the chain.

In this case, the nominal current of the introductory UzO must be equal to or more than the nominal nominal circuit breaker. After an aqueous machine and the circuit breaker, the electrical wiring can be divided into any number of groups, the main thing is that the nomas of group automatic switches correspond to the cross section of the cable used in these groups.

Suppose that in each group there will be at the same time a lot of consumers will be included, and overload will occur on the network. In this case, the introductory machine will work and turn off the internal network from the external power supply. Uzo in this situation will not be overloaded, because Its rated current is equal to or more than the nominal nominal circuit breaker.

The introductory UDO is installed after the introductory circuit breaker.

In the group, the UZO is first installed, and after it is a circuit breaker (if the Uzo is installed per group), or several circuit breakers (if one UzO is installed immediately into several groups).

The rated current of the group UzO is selected so that it is equal to or larger the sum of the group automatic switches. If the sum of the group automatons rating exceeds the nominal circuit breaker, then the rated current of the RCD is selected equal to the nominal current of the inner / RCD, and if the introductory UzO is not set, then equal to or more than the nominal circuit breaker.

Step 4.

Select the Type of Uzo.

In the household wiring, two types are usually used:AC and BUT.

In detail, various types of UzO I have already considered in the article. I remind briefly.

The most common type AC.Protects from the current leakage of the sinusoidal variable form.

However, in modern household devices, TVs, computers, power tools are used rectifiers, pulse power supplies, thyristor regulators, which, when testing insulation, can create pulsating DC leakage currents. At such leaks of UDO type AUs do not react, therefore it is desirable to use the Uzo in residential apartments type A..

Step 5.

By constructive execution should be chosen electromechanical Uzo.They, unlike electronic, do not require any nutrition for their work and enough for their triggering to appear to appear differential current.

The difference between the electromechanical RCO from the electronic I considered in one of the previous articles.

Step 6.

The next step - choice nominal Conditional Current Circuit I NC. This parameter determines the reliability and strength of the device, the quality of the execution of its mechanism and electrical connections.

It is better to use it with an indicator of 6000 A. By the way, in European countries are not allowed to operate URO with this indicator, less than 6000 A. If the house is new and there is a transformer substation, then this parameter, as well as the disconnecting ability of circuit breakers, At least for the introductory RCO, it is desirable to zoom in to 10k.

Step 7.

Selectivity.

I have already considered the issue of selectivity in detail in publication.

Therefore, here we will not dwell on this issue and go further.

Step 8.

Choose temperature execution. Standardly RCDs are calculated on the range of ambient temperature from -5 to + 40 ° C.

However, if, under the operating conditions, more "frost-resistant" UzO is needed, it is necessary to select with the symbol on the front panel, they operate in the temperature range from -25 to + 40 ° C.

Step 9.

Degree of protection of the UDO.

In the standard version of the Uzo are issued with the degree of protection of the IP20 and on the case it is not specified. In case another design is needed, we select it according to the directory for a specific brand.

Step 10.

Select the manufacturer (brand).

We chose the basic parameters of the Uzo, now we choose the brand and manufacturer. To do this, it is convenient to use product catalogs of a particular manufacturer, which can be found and downloaded on the Internet.

To comply with selectivity, use the devices of one brand and one series. It is convenient to order at once the entire set of electrical protection from the official representatives of your chosen brand.

See the video version How to choose a circuit. Part 2:

So we disassemble all the subtleties and moments that you need to know when choosing a protective shutdown device for domestic use.

On this, a series of publications on the UDO within the framework of the course does not end.

Want to know about the release of new materials on this topic? Then subscribe to the site newsletter and you will receive a message about the appearance of new articles on the e-mail.

Firmly deciding with the help of the RCD to protect your family from the electric current, and your home from fires, you need to correctly calculate the characteristic indicators of protection and consumption, in order to find a suitable nominal value.

Three-phase and single-phase UZO

First of all, it is necessary to clearly realize and distinguish between the parameters of the most protective device and the characteristics of the connected consumers of electricity.

UDO parameters and examples

On the housing of the RCO indicate:

• ICZMAX - short-circuit current limit (KZ) no more than 0.25С. - dependent on the cross section of the conductors, and their lengths, approximately equal to the distance to the supply transformer substation. What it is closer, the bigger it will be ICZMAX. This parameter is indicated in the form of a number circled;

Explanation. In practice, it is used: for private residential buildings ICZMAX \u003d 4500A, for apartment ICZMAX \u003d 6000A, for industrial installations ICMAX \u003d 10000A.

• Un - rated voltage, 220V for single-phase, 380V for a three-phase network;
• In - nominal (working) current. This parameter is selected for one value greater than that of the protective machine. That is, you need to pre-calculate the load of the network by losing the current consumed by all devices.

Explanation. If the introductory automatic is regulated by the technical conditions, then it is no longer necessary to read, simply select the following value from the row: 16, 20, 25, 32, 40, 63, 80, 100.
For example, if the machine is installed 25a, the Uzo should select 32A;

• IΔn is a differential leakage current, a distinctive parameter, characteristic of only protective shutdown devices and diphants (UZO + automatic). It has a number of values: 10, 30, 100, 300, 500 mA;

1. IΔn \u003d 10mA - for individual household appliances or groups: electric stove, refrigerator, washing machine, boiler; Power supply in the bathroom, bath, basement, - that is, to power the electrical appliances with a metal case in places with high humidity;
2. IΔn \u003d 30mA is the most popular parameter for installation at entering the entire home or apartment;
3. IΔn \u003d 100mm and more - used to ensure fire safety of branched energy systems. The procedure for calculating IΔN for such needs is presented below.

Table of some parameters of the UDO

Differential leakage current type, causing the operation of the device, is denoted by letters or symbolic symbol:

• AC - IΔN variable. Designation - sinusoid. Used for electric heating devices, lighting systems, electric motors;
• A - iΔn variable and pulsing permanent. Preferably, its use for connecting refrigerators, washing machines, other equipment, in which a dangerous constant voltage may appear on the housing. The most popular in everyday life;
• In - iΔn variable and smoothed permanent - used mainly in industrial installations;
• S - Provides selectivity (selectivity) of triggering devices of protection. Has a time delay 0.1-0.5 s. It is used to install on entering large facilities with a large number of consumers and increased electrical safety requirements. For example, if the hotel is lounged in the hotel a hair dryer in the bathroom, the entire hotel or floor should not be disconnected, but only the device for this consumer.
• G is also used for selective protection with high resistance to false response, has a delay of 0.05-0.09 C;
• The degree of protection of the IP20 (the most common option) means that the device has a second class of protection against touches and zero class (no) moisture proof. If devices are required in wet places, you need to be interested in the second digit of this parameter;
• The manufacturer's logo is an important characteristic requiring a special consideration that goes beyond this article. Attention should be paid to the reputation of the company, customer reviews, as well as to the appearance of the product itself - slopfully applied designations, poor-quality assembly, the irregularities of the joints should woisten the buyer. A distinctive feature of producers is the wear resistance of the product.

Uzo close-up. You can consider the parameters

Temperature mode. For conventional devices is in the range of -5 + 40 ° C, but in the post of Soviet space, the special performance devices were specially popularity: -25 + 40 ° C;

Electrical circuit. For not a specialist, she can not say anything about, but it is necessary to pay attention to the presence of a triangle that denotes the amplifier, which means the belonging of the RCD to the electronic type.

They are cheaper, but less reliable, especially under the conditions of unstable network voltage - the electrical gain circuit feeds, inclined to failure under these conditions. When a zero and simultaneous leakage of phase voltage, this system will not work.

Description of the parameters of the UDO on the housing

It is worth recalling once again that the Uzo apply only together with protection machines.

Taking note of the above characteristics, knowing the nominal value of its introductory protective automaton, for a country house or apartment you can make a choice of the RCD, operating only by these data, not the adhesive complexity of electrical calculations.

An example of the choice of UZO without calculation

Suppose the input automatic in \u003d 20a. A suitable value of the nominal safety device will be 25A, type A (this requirement is often found on many household electrical appliances). For the input device IΔn \u003d 30 mA, for individual electrical appliances IΔn \u003d 10 mA. (In this case, it is also necessary to put a consistently protective automatic machine, in which the load is selected accordingly).

The value of IN UZO should also be higher for one value.
In order to choose a suitable RCO of fire protection for large branched networks, first need to learn the total current consumed Iς by all devices.

Iς \u003d IP1 + IP2 + IP3 + ... IPN

In the case of calculating power, calculate iς can be based on the formula:

where Pς is the total power.

Then you should calculate the total leakage current IΔς. According to the request of the Pue 7.1.83, if I cannot know the leakage current IΔP in a particular electrical receipt, it is selected equal to 0.4 mA per amper load, and the value of IΔL \u003d 10MK \u003d 0.01ma for each meter of the length L of phase wire is received.

note

Having an already calculated value iς, you can calculate IΔς \u003d 0.4 * iς + 0.01 * L. Also, the aforementioned PUE paragraph requires that the nominal differential disconnection current of the device exceeded three times the total leakage current.

The final formula for calculation becomes like:

IΔn \u003d 3 * (0.4 * iς + 0.01 * L) \u003d 3 * iΔς

Specific example with the calculation

I mean low temperatures (special temperature performance, -25 ° C), no gas (heating and cooking and cooking only due to electrical appliances), the presence of refrigerators, washing machines, boilers, various household equipment. We assume that the calculations for individual groups of users are already produced, it is required to calculate the overall input protection device (type S).

You can find out the consumption current for each device from the drive's passport, using the calculator to produce calculations. We accept the conditional settlement value Iς \u003d 52a. The nearest value of the protective machine - 63a, respectively, in the Uzo will be 80A. Using a ruler, roulettes to measure the length of the entire cable of the voltage, regardless of the connection to the load.

We will assume that the length of the wires in the amount of 280 m. We substitute the data in the formula: IΔn \u003d 3 * (0.4 * iς + 0.01 * L) \u003d 3 * (0.4 * 52 + 0.01 * 280) \u003d 70 , 8 (MA).

The nearest value iΔn \u003d 100mA will be sufficient to ensure reliable protection without false positives.

Final Uzo:
80A, type S, IΔn \u003d 100mA, T -25 ° C.

How to choose the right ed

Content:

One of the devices that are of great importance in the electrical engineering is a protective shutdown device. Its main purpose is to disconnect from the power of the entire electrical network or its separate area by opening the contacts. Thus, protection against electrical damage and fire prevention is ensured.

In modern electrical engineering, the use of these instruments in many cases becomes mandatory, therefore, the question often arises how to choose the RCD.

These protective devices are applied not only in single-phase, but also in three-phase networks under various loads, therefore, their choice is carried out depending on the specific operating conditions.

Purpose of the UZO and the principle of work

The main task of the RCD is the neutralization of currents in the event of various damage in electrical installations. The protective shutdown device serves as the most efficient protective agent. Unlike fuses or automata, the RCD is capable of breaking the chain for a split second and save human life.

Danger represents not only the likelihood of direct electric shock. Sometimes there is a fairly simple touch to the details of the instruments and devices that are under voltage. Therefore, protective devices must be activated in a timely manner. In order to properly solve the task, how to choose the Uzo for the house, the conditions in which it will function should be taken into account.

In the work of protective devices, the phenomenon of electromagnetism is used. In this regard, the design of the RCO includes coils with a magnetic core, connected to current-carrying wires transmitting electricity to the consumer.

At the same time, the magnetic flux occurs, which is an arithmetic amount of currents flowing through these conductors. In this case, incoming currents are positive, and the outgoing is negative. In the absence of leaks and closures, they will be equal and in the amount will be zero.

Such a state of the chain indicates the health of the installed equipment.

In the event of a leak, a partial reverse current of the current conductors occurs, which leads to an imbalance. The difference in differential currents causes the excitation of the magnetic flux in the core. Its value will be proportional to the difference in electrical current. When a certain threshold is reached, the device works and turns off the power supply to consumers.

How to choose the right

In order to select the optimal version of the protective shutdown device, it is necessary to know its main parameters. Devices with different characteristics are used in specific conditions that need to be considered when choosing.

The nature of the leakage currents allows you to divide them into different types. This division depends on a smooth or sudden increase in current.

Uzo with such characteristics was most common as the most suitable for the widest conditions of operation.

The response technology allows us to divide the RCD on electromechanical and electronic. In the first case, the high-precision mechanisms are triggered as a result of leakage currents. These are the most reliable and expensive devices capable of working under any conditions.

Electronic devices are cheaper, however, for normal operation of electronics, use of external power supply. Their effectiveness is significantly reduced when the voltage drops occur. The trigger speed of the UDO allows them to be used in multi-level protection systems.

This allows you to disconnect all the emergency sites.

There are other parameters requiring knowledge of electrical engineering. Therefore, when choosing an RCD, it is best to seek help to qualified specialists. However, if the exact characteristics of the electrical network are known in advance, you can independently select the most suitable protective device. Among them are the most important following:

• Voltage. The UDO can be calculated on a single-phase network with a voltage of 220 V or three-phase - at 380 V. The first option is usually used in apartments, and the second is in private homes, cottages and cottages. If there are sections with one phase in three-phase wiring, then protective devices designed for 220 volts are used for them.
• Number of poles. In single-phase networks, bipolar UZOs are used, calculated on one phase and zero, and in three-phase - four-pole devices to which three phases and zero are connected.
• Rated current. It is a bandwidth of the UZO, depending on the number and power of the connected electrical appliances and equipment. Consequently, this indicator for the overall (introductory) security device should be designed for all established consumers. For linear Uzo, the total power is calculated based on the number of devices on a line or another line. Nominal Uzo, installed by manufacturers matter 16, 20, 25, 32, 40, 63, 80, 100 A.
• Current leakage UDO. The value when the shutdown is reached. It also differs in the rates of 10, 30, 100, 300 and 500 mA. For ordinary apartments, the device is best suited for 30 mA. With a smaller denomination of the current, the device will constantly react even to minor fluctuations on the network and turn off the power.
• Type of leakage current. On the body of the device, the symbols of the AU, A, B, S and G are applied. For example, the AC reacts only to the alternating current of leakage, and B - on constant and alternating currents. The rest of the label also corresponds to certain parameters, including the detection of the device shutdown.

What are the Uzo

The main classification of protective shutdown devices occurs at the current of their triggering. For example, fire fighting devices react to currents at 100, 300 and 500 mA. They protect wiring from fire when insulation violation and short circuit.

Usually, the introductory UzO is installed for the electric meter and ensure the protection of the entire object. For people, electric current becomes dangerous at 50 mA. Therefore, devices protecting against fires are not able to protect a person from shocking.

For these purposes, devices that turn off the network are used when the current reaches a value of 10 or 30 mA.

Protective devices differ in the number of poles and can be used in single or three-phase networks. Each type of devices is characterized by a functioning method. The marking applied to the body of the device must be properly decrypted and to know exactly what it means:

• AC - Category UzO, used only in AC networks. Accordingly, the device reacts only to alternating current.
• A - Protective devices of this category are triggered not only with a variable, but also at constant current.
• B - has more advanced features and reacts to three types of current. In addition to constant and alternating, the device is turned off when the differential current is straightened.
• S - selective devices with the possibility of time delay when disabled.
• G are also selective devices, but with a smaller time delay.

The RCD classification occurs on technical execution. This allows you to better pick up the RCO. Most often electromechanical devices are used, which does not have its own power supply. They are triggered and disconnected by the appearance of differential current.

Another type refers to electronic protective devices requiring connection to an external power source. In this regard, the reliability of protection is reduced, so such RCOs are applied less frequently.

When you turn off the additional power, they turn off the network automatically, when the network is renewed, the network is also automatically turned on.

Separate device designs do not provide for automatic switching on the circuit when the power supply is resumed.

How to choose the UZO by power

Unlike automatic switches that protect against overload and short circuits, the protective shutdown devices are designed to protect against current leaks. The reason is the faulty insulation of electrical appliances or contact of the current-carrying parts with the housing. In these cases, an instantaneous disconnection of the RCDO, de-energizing the line, protection of consumers from lesion to the current.

In order to perform the calculation of the Uzo by power, you need to know the total number of consumers connected to this line.

In the event that the question is solved, how to choose the UDO and the power machine, both protective devices must have appropriate values \u200b\u200bthat ensure their normal operation.

If the installation of circuit breakers is not provided for by the project, in this case the cumulative power consumed by electrical appliances is calculated. As a rule, this value in the standard apartment of a multi-storey house does not exceed 25a.

When installing the UDO in private houses of all consumers, it is recommended to divide into groups connected to individual lines extended to each floor, economic buildings, outdoor lighting, etc.

If the Uzo has less power than the available consumers, it will be constantly disconnected due to overloads. That is, the device will actually not work normally and will not be able to protect the line.

Partially solve this problem will help sockets with an UPO mounted in them, calculated on current consumption in 5a.

How to calculate Uzo.

In order to calculate the protective device and solve the problem, how to select the power UDO, the parameter table will help to make it as quickly as possible and accurately. It is necessary to use two technical characteristics of leakage and maximum current to obtain a desired result. The calculations use a 220 V network voltage, with a frequency of 50 Hz.

Calculation and choosing the nominal NMO maximum current is fairly simple. It is necessary to set the value of the total electrical power of instruments and equipment included simultaneously.

For example, if this indicator is 6000 watts, then the value of the calculated current will be: i \u003d p / u. Substituting the necessary values \u200b\u200bin the formula, we obtain the result: 6000W / 220V \u003d 27A.

note

The nearest RCD from the standard range of nominal currents will be 32A.

If the current leakage current is calculated, in this case a simplified scheme is applied, according to which various types of protective devices are selected in accordance with the operating conditions of objects:

• In ordinary residential premises - for 30mA.
• Bathrooms, kitchens and other facilities with high humidity and higher electrical safety requirements - on 10mA.
• On large objects with electrical networks, with a length of over 1000 m or input - 100mA.

Quite often, there is a need to select the UDO on the machine group, the calculation of which is performed according to certain rules. The installation of these devices into the chain is carried out in series, the automata can be installed both before and after the RCD.

Current values \u200b\u200bof circuit breakers must be lower than in the Uzo, but no less real consumption current.

The correct calculation of the UDO and automata shows that in the case of overloads and short circuits, the machine will protect not only the line itself, but also the protective shutdown device installed on it.

Current nominations

The rated currents of the main types of Uzo are 16, 25, 40 and 63a. This value corresponds to the value of the current that the device can pass through itself without restrictions on time. Within this line, it is possible to choose a Uzo for the electrical panel of an apartment or a private house.

The value of the rated current is necessary when solving the question, how to calculate the RCD on the machine group. In this case, it is necessary to choose a machine with a rated current smaller or equal to the rated current of the differential switch.

Experts recommend choosing a stage higher than that of the machine, since he can pass through itself a current, more nominal for a long time. With the equality of currents, during this period, the RCO can simply burn.

What a Uzo to put on entering the apartment

In modern high-rise buildings, it is forbidden to use three-phase wiring, so many owners are wondering how to choose an RCD for an apartment.

Meanwhile, there is nothing complicated here, because for single-phase wiring, a two-pole device with marking AU is used. For the current leakage, the zoo for the apartment is selected at the rate of 30 mA.

Devices with a lower shutdown threshold can provoke false responses.

How much to put in the apartment? It all depends on the total power of consumers. If it is too big, it is recommended to break the home network into separate lines and to put a protective device for each of them. Additionally, the general UZO is installed at entering the apartment to protect against fire during insulation damage.

Often, false responses occur due to the old wiring. If these processes will occur systematically, its complete replacement may be required.

Uzo at entering the house

Unlike a typical apartment, a private house has an individual layout with a variety of rooms.

Therefore, it is often a question arises, what kind of Uzo put in a private house? At such objects, not only single-phase, but also three-phase electrical networks with a voltage of 220 or 380 volts can be used.

Therefore, in the first case, the same UDOs are used as in apartments, and in the second - four-pole, where terminals for the three phases and zero wire are provided.

In addition, the choice of UzO for a private house is carried out by the type of current. However, it should be borne in mind that in private homes, powerful electric motors are often launched, for a short time consuming a powerful starting current. It is recommended to determine in advance which threshold threshold and then choose the necessary device that maintains performance under these conditions.

The question of how to choose a Uzo for a wooden house to protect not only from leakage currents, but also from fires.

To this end, a multistage protection system is used, in which powerful devices prevent fires, and devices with a lower trigger threshold are protected from current leaks.

However, it is not necessary to install the UDO with a minimum cut-off current in 10a, especially if electrolyney has a greater length. The sensitive device will respond to the slightest drops and cause false responses.

How to choose Uzo.

Like any other device, the RCD or as they also call the differential current switches, has different specifications.

The main parameters that pay attention to choice of Uzo.are:

• - voltage of the network 220/380 V;
• - the number of poles, for a single-phase network - bipolar, for three-phase - four-pole;
• - The rated current on which the UzO is calculated. Produced on the rated load current 16, 20, 25, 32, 40, 63, 80, 100 A;
• - the differential current to which the UDO (leakage current) reacts - 10, 30, 100, 300, 500 mA;
• - by type of differential current:

AC - react to alternating leakage current;

A - reacts to the leakage of alternating current and constant pulsating;

B - reacts to a constant and variable;

S - to ensure selectivity has a shutdown time delay;

G - also as s, but has a smaller time exposure.

Errors when choosing a UZO

From the point of view of isolation, absolutely ideal devices do not exist, each electrical appliance has a natural leakage, although very insignificant.

For choice of Uzo. It should be understood that the sum of natural leakage currents can cause a false response of the device. Based on this, there is a rule in which it says that the sum of the natural current leakage currents that are connected to this protective shutdown device must be no more than 1/3 of the rated leakage current.

For example, if the protective shutdown device has a rated leakage current of 10 mA, then the sum of natural leakage currents should not exceed 3.3 mA, for 30 mA is 10 mA, etc.

Therefore, in order for the selected Uzo to be falsely false, it is necessary to take into account the natural leaks of the electrical appliances that are connected to it (high-quality firms manufacturers indicate the leakage current in the passport or on the device housing).

Which protective shutdown device to select?

Consumers of electrical energy over power lines flows the current of the sinusoidal shape, therefore leaks in this case will also be sinusoidal. Therefore, by type of differential circuit breakers, you need to choose - speakers.

Protective Disconnection Device for Apartment

To protect in a regular apartment, the differential current switches are usually called single-phase (bipolar) type - speakers, with a nominal voltage - 230 V and a rated current to 32 A.

The minimum leakage current, which can feel 10 mA. However, choose a Uzo with such a leak current is not necessarily. The fact is that the current value of 10 mA may be a total leakage for electrical dispensers and apparatuses of an apartment as a whole, especially with the old electrical wiring.

A protective disable device Feeling this leak will be false. To protect people from electric shock, there will be sufficient choosing a Uzo with a leakage current of 30 mA.

Protective shutdown device for home

In large houses and cottages, three-phase (four-pole) Differential Switches are installed. To protect for such structures, it is reliable, then in this case it is required to install not a single differential current switch, but several. Power diagram for the house as a rule has a cascade character, with a multitude of branching (especially if the house is a multi-storey).

In this case, the RCO must be installed on each branching. It is usually an introductory electrical panel, first floor, second floor, individual extensions, etc.

To install in the introductory power switch, the differential current switch is selected with a leakage current 100mA and above. By type, there is a place to install a VDT type S. This type of VDT is selective and have a shutdown time.

For individual groups of premises, it is suitable as for the apartment, with a leakage current of 30 mA, and type A or AU.

If the Uzo is planned to be installed in a room with an old, unreliable electrical wiring, then in this case the choice and further installation of the UZO for such premises is not an idea.

As is known, the RCO reacts to the leakage current and for the wiring of the wire of which they have old unreliable isolation (especially in the houses of the old building) small leakage currents arise constantly. Uzo in such cases can work often and usually without visible reasons.

How to choose the right RCD: Calculation of the operation of the operation and power of the machine

Despite all the advantages that electrical energy possesses, it has and cons. The main one is the danger of electric shock.

To protect people from electricity, a variety of devices have been created, and one of them is called the RCO - a protective shutdown device.

But for the organization of effective protection using these devices, it is necessary to present well how to select the Uzo and how to connect it.

The device is an automatic device that turns off the voltage when the differential current occurs (Dyftok, leakage current).

It is he who arises with one or another malfunction of electrical equipment, in most cases a consequence of accidents. The worst thing is that a fault that causes leakage does not show any way.

Washing machine erases, the computer is calculated by the task, the boiler diligently warm water. But it is worth a person to touch the casing of such an appliance or stand under the shower, as an irreparable.

Principle of protection

Electrical equipment, as you know, gets energy on wires. Household appliances use two conductor - phase and zero. If the equipment is industrial or just powerful, then it can use three phases, but the essence of the problem does not change.

So, rudely speaking, the current runs in phase (phases), drives electrical equipment and runs away through zero *. In this case, the incoming and emerging values \u200b\u200bof currents are always equal - how much energy in the device is carried through a phase wire, as much as it turned out through zero.

Suppose there was an abnormal situation - droves the gland in the washing machine and flooded the control board, water got inside the electromazor, the insulation of the wire was pulled due to the vibration, or it happened to the thermal test of the electric motor. For this reason, voltage appeared on the metal parts of the unit.

If the device is grounded, then this voltage from the chassis or casing flows into the ground contour, causing difts. In ungrounded equipment, the leakage will not be, but it will appear if a person standing on a conductive surface (concrete floor, metal or wooden, but wet flooring, etc.), touches the casing.

The occurrence of Dftok through the grounding circuit or the human body

In this situation, the current currently incoming the current will not be equal to the extending to zero. The value of the leakage flowing into the ground is added to it: IPhaza \u003d Inever + Items.

The task of the UDO is precisely in the definition of this shame. In the process of operation, the device constantly compares the current value passing by phase and zero. While they are equal, everything is in order. As soon as the phase current exceeds zero, the device emergency turns off the voltage.

Characteristics of the protective shutdown device

From how much you choose the protection device, your health will depend on, and perhaps life. That is why it is necessary to approach this issue with full responsibility. What is characterized by the UDOwho have another name - differential switches (not to be confused with automata)?

• Differential current. The main parameter of the device. In essence, this is the sensitivity of the protection system. For example, the differential switch shown below will work when leakage of 30 mA (position 3 in the photo).
• Operating current or power. Current load in amperes, which the device can long withstand without damage and overheating (position 1).
• Operating voltage. The maximum voltage of the network in which the UDO will be embedded (position 2).
• Voltage genus. The supply of the network in which the protection device will be embedded. It may be variable, constant or variable + constant (position 5).

How to choose Uzo.

Obviously, each of the above parameters is equally important when choosing a RCD. A device with low operating voltage and power will simply burn, and the wrong choice of the Dftka value and the kind of voltage make the device absolutely useless - it either will be falsely to work, or will not work at all.

Choice by diftoku

This is the main and responsible selection criterion. We'll see, how to calculate the UzO for a specific object. According to PEU, the permissible leakage value in electrical installations is taken at the rate of 0.4 mA per 1 and current load.

Additionally, it is necessary to know the length of the electrical circuit and add to the resulting result by another 0.01 mA per each meter of the supply wire. Agree, this calculation of the Uzo for, say, the house wiring is quite complicated and time consuming.

But it is possible to do everything much easier, and the level of protection does not suffer.

If the device is planned to be installed not for fire safety purposes, but to protect people (usually this is the main task in house networks), then it must confidently respond to a leak of no more than 50-80 mA.

This value is considered extremely permissible for the human body.

On the other hand, if the house network is very extended and branched, and even with rawrooms (the same bathroom), then the magnitude of the natural leakage distributed over the entire line can be higher than the same 50 mA.

note

How to be here? To put a more powerful device, how do some "specialists" recommend? In no case! After all, if you, God forbid, get to the tension, powerful automation will not be able to save you - it either will work after passing through the body of the deadly current, or will not turn off at all. In any case, the person himself will still be anyway.

Exit from the situation is not the choice of a coarsest Uzo, but the installation of several sensitive devices, each of which will follow the individual section of the chain. For example, one device on the bathroom and kitchen, another on the sockets, the third - to the lighting.

Power and voltage

According to these criteria, the choice of UzO is much easier. The magnitude of the voltage in the networks is known to you: with a single-phase line it is 220 V, three-phase - 380 or 660 V. Rod of voltage in both cases variable. If your network is single-phase, then the device can be selected single-phase. If the phases are three, then the diploma will need three-phase.

Single phase and three-phase differential switches

Now about how to choose the UDO and the power machine. Why and automatic? The fact is that the differential switch does not work from overload or short circuit, and reacts only to the differential current. It happens in the KZ house, the Diphaptomat will safely burn from overload along with the wiring. Therefore, the installation of the UZO in a pair with a machine is mandatory.

As for the operating current of the differential switch, it should be no less than that the introductory machine is calculated. If you already have the circuit breaker, just look at what current it is designed. If not, it will have to put it.

For a regular apartment without particularly powerful consumers, it is usually enough with a capacity of up to 32 A, withstanding a load of 7 kW.

Here it should be noted that the voltage and the rated current indicated on the housing of the switch and the machine can be greater than necessary, but never less.

How to connect Uzo.

In order for the differential switch for a long time and reliably worked, it must be properly installed in the house scheme. Here are some mandatory conditions that need to be performed when installing the UDO:

1. Proper phasing. In order for the diffusion switch to control the difference in phase and zero currents, he should be able to distinguish them. Therefore, the phase and zero wire must be connected to strictly defined terminals indicated accordingly on the instrument housing. If you confuse zero and phase, then the device will either constantly work, or does not turn on the protection at all, which is worse. In multiphase devices, the phase sequence can not be taken into account, but the zero should be strictly in its place.
2. Mandatory protection against KZ. As mentioned above, the RCO does not have its own short-circuit protection, therefore should be installed consistently with the machine. Where it will stand the machine - before or after the Uzo, the role does not play. It is allowed to install one machine into several UzOs and vice versa - the output of the differential switch can be loaded into several automata serving different lines.
3. Protection against external influences. Almost all the UzOs do not have protection against moisture, so it is necessary to place them in dry rooms or in special closed cabinets. Otherwise, the device may refuse the most inopportune moment with all the ensuing consequences.

Connection option of the UDO to the house network

Checking the correct connection

After the protection device is set, it is necessary to check the correctness of its operation, so as not to know about the problems in the post-factum connection - occasionally under the voltage.

The check is carried out by two methods - a test button and artificial leakage current creation. The first is exceptionally simple - press the button located on the UDO housing and signed accordingly.

The scheme built into the device will create a leakage current imitation, and the protection will work, de-energized the line.

If you do not trust this button (you never know what and what does it imitate), then you can check the device with artificial creation of leakage current. Connect between the phase contact of the outlet and its ground terminal, some electrical appliance - a table lamp, a soldering iron, etc.

Diagram of checking the correct operation of the differential switch

The Uzo will immediately notice the leakage and immediately turn off the chain. Everything is fine. If your sockets are not connected to a grounding contour, which is very good, then a semi-meter pin, stuck in the ground, can be used as a grounding contact. This, of course, is not a complete ground, but the current through it is more than enough to ensure that the RCO fixed the leakage.

DIFAVTOMAT AS OPTION OF DOUBLE PROTECTION

There is another device that can work from the leakage current. It is called differential automatic.

Its difference from the usual UzO is that the device additionally has an automatic switch that reacts to a short circuit.

The installation of the DIFAVTOMATA makes sense if you do installation from scratch or your wiring does not have a machine at all. By buying a diphawtomat, you get two devices in one case - Uzo and automatic. It is cheaper, and easier to install.

The rattomate appearance is similar to the protective shutdown device, but has a built-in automatic

The choice of differential automaton is made according to the criteria:

1. Differential current.
2. Rated current.
3. Operating voltage.
4. Rod of current.
5. Cutching current.

Almost all of this list you probably have a sign - you chose the UZO. It is suitable for choosing a rattomate. An additional criterion is only a cut-off current, which is triggered by the automatic built into the device. It is usually equal to the triple operating current, so if you have chosen the working current correctly, the cut-off current will be optimal.

How to choose a Uzo for an apartment or private home?

On the appointment of the UDO has already been repeatedly mentioned, and it is definitely its installation in a modern household power grid is the most important human protection from electricity defeat. But how to choose a Uzo? Based on which parameters? How to calculate the device for one or another protected consumer? We will try to figure it out.

To make the right choice of the UDO, you need to understand its purpose, the main characteristics and parameters. When you buy the device, pay attention to its body, all important information is indicated. So that these numbers and letters tell you about something, we will analyze each of them separately.

Purpose

Most importantly, what needs to be understood, the circuit breaker protects the electrical network from superhoks, and the RCD ensures human protection.

If, as a result of a breakdown of isolation on the body of an electrical appliance, the potential appeared, when touched it, there is a possibility to get a stream.

So that this does not happen, immediately when current leakage occurs, the protective shutdown device will respond and turn off the damaged section of the chain.

It's important to know! The UzO does not protect against overloads and short circuits, so automatic switches are connected in a circuit.

Trademark

Speaking about the brand, we, in fact, will disassemble the ratio of price and quality. The fact is that there is a chemless classification of all UZO manufacturers in their territorial location - European models, Asian and Russian.

One way to distinguish fake on video:

Each of them products have their own characteristic features:

1. And the fireproof RCD, and the device that protects people from electricity lesion produced in Europe will be an order of magnitude more expensive than the models of Russia and China. But such a price guarantees quality and reliability. It will not be worthwhile to know that some companies in Europe, in addition to the main high-quality range, are issued for the markets of other RCD countries with the same reliability, but with underestimated technical characteristics.
2. Domestic manufacturers offer an RCD with a lower price than europe, nevertheless, they respond to all regulatory requirements of Russian standards. While the manufacturers of Russia, the trading network is not so strong, and the devices themselves are not able to compete with Asians at a price, with Europe in terms of quality.

1. Uzo Asian manufacturers have the greatest demand in the world. Some manufacturers from Asia make contracts with a supplier of products to the Russian market and in this case produce devices under the trademark of Russia.

Before you choose a trademark of the RCO, decide what means you have for arrangement in an apartment or in a private house of protective automation. The most preferred firms:

• swiss "avv";
• french "Legrand" and "Schneider Electric";
• german "Siemens" and "Myllle".

Among domestic producers, products are most widely used:

• Kursk plant "CEAZ", the average price and quality, the guarantee for the issued UzO firm gives two years, which indicates the reliability of products;
• INTEREEKTROKOMPLEKT MOSCOW FIRM (IEK), not always positive feedback gets products, nevertheless, the demand for it is large due to low cost;
• Ulyanovsk plant "Contactor", he is included in the group of LEGRAND, which affects the quality of products and respectively;
• the relatively young St. Petersburg firm "DEKRAFT", in the Russian market, is a company with a global name "Schneider Electric".

As for Chinese manufacturers, they produced by them of the RCO are direct competitor to the devices of the Russian firm "IEK". The price and quality are approximately at one level, while the warranty period of the Chinese goods is five years.

Main settings

After the brand on the housing, the main nominal and performance of the UZO are designated.

1. Name and series of model. Please note that here you will not always see the letters of the UZO, some manufacturers are denoted by this device as a VDT (Differential Current Switch).
2. The magnitude of the rated voltage and frequency. In the Russian power system, the operating frequency is 50 Hz. As for the voltage, then for a single-phase network in the apartment is 220-230 V. For a private house, a three-phase network is sometimes necessary and a working voltage will be 380 V.

Characteristics of the Uzo on video:

1. Nominal working current, this is the maximum value that the RCD is capable.
2. Nominal differential disconnection current. This is the value at which the device works.
3. Also, the temperature limits of the UDO operation are indicated here (minimum - 25 degrees, maximum + 40).

1. Another current value is the nominal Conditional Code of the KZ. This is the maximum short circuit current that will withstand the device and will not turn off, but provided that the chain will use the appropriate automatic with it.
2. Rated response time. This is the time interval from the moment when a current leakage suddenly occurred and before it should be reset all the poles of the Uzo. The maximum permissible value is 0.03 s.
3. Mandatory on the housing should be drawn the circuit of the RCD.

Shape of current leakage

By this parameter, all devices of the protective shutdown are classified into three types:

1. "BUT". Such a device is triggered to shut down with instantaneously arising or smoothly increasing current leaks having a sinusoidal variable or pulsating constant form. This is the most common type of Uzo. Due to the fact that it controls both alternating, and the constant current is characterized by a higher cost.
2. "AS". Also common and more affordable device. It works only on the occurrence of variable sinusoidal current leakage.
3. "IN". This device is mainly used to protect industrial premises. In addition to the variable sinusoidal RCO, reacts to the straightened and pulsing form of a constant current leakage.

There is a fully logical question, in household networks there is an alternating current of the sinusoidal form, maybe it can be enough to install devices like "speakers"? But if you carefully study the characteristics of modern household appliances, most of them have power supplies with electronic semiconductor components, reaching which sinusoid is converted to pulse semidewrites. And if the leakage is not a sinusoidal character, then the Uzo of the "AU" type will not lock it and will not turn off.

That is why the manufacturer specifies in passports to many household appliances, which is necessary to connect through which update.

Tips for choosing a Uzo on video:

Operating principle

There is an electronic and electromechanical circuit.

The second is more expensive, but does not depend on the supply network. It will work as soon as a current leakage occurs in the circuit.

The electronic type device in its work depends on the enhancer built into the electrical circuit. And so that this amplifier is always in working condition, it requires an external power source. In this regard, the reliability of the response is reduced.

Selectivity

The selectivity of the device for the protective shutdown is two types - "G" and "S".

These UzOs are triggered after a certain period of time, called shutter speed. Apply them when several devices are consistently connected to the circuit.

To protect the exhaust consumer branches put devices without exposure time, and at the entry of the UZO type "G" and "s".

If a current leakage occurs, and the outgoing UzO has not responded, then a certain time should turn off the device on entering.

Uzo type "S", the exposure is rebuilt ranging from 0.15 to 0.5 s, like "G" - from 0.06 to 0.08 s.

Two-level fire protection

For a wooden private house, a fire safety guarantee is especially important. Therefore, in this situation it is necessary to choose the RCDO, planning a two-level differential protection system. Its main goal is that the protective function is divided:

• fireproof UzO provides triggering at high current leaks that contribute to fire;
• ordinary devices will prevent the defeat of the human electric current at low leakage values.

Since the fireproof UzO is of great importance of the rated current leakage, in itself it will not protect the person. Therefore, it is always installed in conjunction with the Uzo, which has less leakage current.

Regardless of which value of the nominal working current and how many poles has a fireproof Uzo, the leakage current parameter in such a device is 100 mA and 300 mA, in the rest it does not differ from ordinary.

The connection scheme is performed sequentially, closer to the power source (at the input), we put the fireproof RCD, and on the exhaust branches of the versatile wiring protected.

Visually about fireproof RCO on video:

This looks like this: the introductory UzO is selected with parameters 63 A (rated operating current) and 300 mA (leakage current), the remaining devices, respectively - 40 A and 30 mA for the socket group, 25 A and 10 mA for the bathroom, 16 A and 10 mA for the lighting group.

The use of fire fighting devices is advisable and in the apartment. Often, the lighting group is left unprotected from leakage currents. With a minimal probability, but high current leaks may occur in this branch, and if such an RCD is put on entering, it will be a kind of substrate.

Execution of calculations

Not always in practice, you can perform an accurate calculation of the total leakage current. Therefore, it is about it to be determined by the following method: 0.4 mA current leakage takes a capacity of the load. It should also be calculated based on the length of the phase wire - 10 μA is taken on 1 m.

Suppose you need to properly select the RCD for the power of the electric stove (3 kW). To begin with, we carry out the calculation of its load: 3000 W / 220 V \u003d 13.64 A. Leakage current for the plate: 13.64 A x 0.4 mA \u003d 5.46 mA. Similarly, we make calculated for the padded conductor, for example, 10 m: 10 μA x 10 m \u003d 100 μA \u003d 0.1 mA. In the amount of the leakage current, it turned out: 5.46 mA + 0.1 mA \u003d 5.56 mA.

note

The resulting value of the amount of current leakage should not exceed 33% of the differential rated current of the UZO. And then the calculation of the school lessons of mathematics, we prepare an elementary proportion and we obtain: 5.56 mA x 100% / 33% \u003d 16.85 mA.

There is a special table of standard values \u200b\u200bof the rated leakage currents, based on it, a device for 25 mA is suitable for the electric stove.

How to choose a Uzo for an apartment or at home you now know, and you can determine the total calculated leakage current. If at least we doubt your knowledge and abilities, invite a professional electrician to fulfill this work. Do not forget that the protective shutdown device is a guarantee of your safety.

We choose the UZO according to the characteristics of various types of devices

Differential current switch (UZO) reduces the likelihood of electric shock in rooms, the occurrence of fires by protection against leakage currents. Therefore, in our time, this type of protective electrical equipment is in high demand. The article will help to choose a power UDO, taking into account the design and different types of device classification.

Classification of protective shutdown devices by different criteria

By the number of poles, the UDO is divided into several groups, of which interests are of:

• Two Poly Uzo. - Designed to work in single-phase networks. They are most often produced in the form of modular equipment and occupy two places for DIN (35 mm) in standard electrical parses.
• Four-pole Uzo. Work in three-phase networks and occupy 4 places according to DIN standard (70 mm).

By the form of the design of the UZO there:

• Electromechanical Uzo.where the mechanism for measuring differential currents works independently of the loss of voltage in the network due to the burst of zero, since the differential transformer responds only to the difference in currents. Such UZOs have a very thin mechanics, which explains their higher cost.
• Electronic Uzo. - In which the current comparison occurs in electronic comparators, then the difference signal is enhanced to actuate the separator. Such UZOs have electronic circuits that require a stable supply voltage.

The reliability of electronic RCD is less, but the lower price justifies their widespread use.

Under the conditions of functioning, when the constant component of the differential current of the circuit occurs:

• AC typeA variable sinusoidal differential current, which can increase slowly, and may occur with a jump.
• Type A.The sinusoidal current reacting, as well as the straightened pulsating constant, which can also slowly increase or occasionally jump.

Uzo type and more complex and therefore have a large price.

In addition to the modular, installed in the shields, there are special types of UzOs that have the shape of a socket or even an electric fork.

Such application is justified in cases where electric wiring in the apartment or house, having a small insulation resistance and, accordingly, large leakage currents.

The Uzo installed in the shields in such cases will have frequent false responses, which will make it impossible to work the electrical appliances.

The right choice of UzO for the apartment must be justified by specialists who make the project of the power supply of the premises or the whole house, because you need to consider many technical nuances that can be known only to electrical engineers. The project is better to do in the construction of a new home or with overhaul of housing, which must include and repair or fully replacing the wiring.

Uzo selected by nominal current In, which can skip the device in continuous modes of operation.

This value can be from 6 to 125 amps. Another important characteristic is a nominal disconnecting differential current. IΔn.at which the UDO is triggered (more on the principles of operation of these devices can be found here).

This parameter has fixed values: 10 mA, 30 mA, 100 mA, 300 mA, 500 mA, 1 A and selected based on safety requirements.

For example, if the RCD has a differential current of the operation of 30 mA, then this is done for the safety of people and animals, because such a current does not lead to strong defeats.

Switches with differential trigger current 100 mA and above Calling among specialists fireproof Uzo.which will turn off the entire wiring when the leakage currents have already occurred for a person.

• High leakage currents concentrated locally in one place can lead to a large amount of heat capable of changing fire.
• Very often, not all electrical circuits are protected by UZO, for example, lighting circuits. The presence of a hydraulic fireproof RCD will save from high leakage currents, which can also be caused by fire.

Electrical equipment installed in the bathrooms requires the protection of the UDO with a differential current of 10 mA.