It is necessary to carefully and responsibly think over what UZO to put in a private house. The device must have the necessary operating power and in all technical parameters correspond to the electrical system in the room. How to correctly select the security element that meets the requirements?
We will tell you how to find a device that will function correctly for a long time. The selected model will protect the housing from fire situations, protect the equipment from burnout, and users from burns and electric shocks. The list of the best deals on the market will help in the selection.
The content of the article:
- General description and purpose of the device
- Design features of devices
- How does the protection device work?
- Functional classification
Main parameters of the product selection
- Selection by type of network voltage
- Number of poles at the instruments
- Throughput current level
- Leakage current difference
Top RCD manufacturers
- ABB Automatic Products
- What offers users IEK
- Nuances of products of the enterprise Contactor
- Classic installation solution
- Conclusions and useful video on the topic
General description and purpose of the device
The abbreviation "RCD" stands for a protective device off.
The unit is used for such important purposes as:
- differential protection of a person from current shocks at the moment of touching a household appliance, which due to various circumstances under stress;
- protection of residential real estate from fire caused by low-quality insulation of house electrical wiring.
From the physical point of view, the basic function of the device is to protect the power grid from high currents leakage by instantaneous and complete shutdown of the system at the moment of fixation of indicators exceeding the maximum allowable norms.
Some parameters of the RCD mounted in the instrument panels can be set using a practical and convenient multimeter or indicator screwdriver
There are certain requirements for installing and using the module. You can learn about them clearly and in detail in relevant documents, for example, in recent editions of OLCs or in brochures describing currently relevant series of standards for electrical installations IEC 60364 and the impact of electric current on people IEC 60479-1.
Design features of devices
The device of protective shutdown is arranged not too difficult and consists only of four main working elements, such as:
- differential current transformer;
- a special mechanism responsible for breaking the connected circuit;
- electromagnetic relays;
- check node.
Counter windings - zero and phase - are connected to the transformer device. When the network operates in the normal standard mode, the conductors in the region of the transformer core control the magnetic fluxes, which initially have the opposite direction.
By type of construction safety shutdown devices divided into electromechanical and electronic. Products of the first type are a simplified type of safety module, and work immediately during the primary fixation of current leakage, no matter what voltage is currently in network.
The main working component of an electromechanical device is a toroidal core with windings. When a leak occurs at the device’s responsibility area, a voltage is generated in the secondary winding level to activate the relay. This process causes the mechanism to shut off the network.
For correct operation, the device does not need an external power source. It has good operational stability, since it has no electronic design parts that can be damaged or burned when the network is overloaded or as a result of sudden surges voltage.
It is quite cheap and is sold in almost any store that implements the range for household needs or the construction of electrical networks. It works reliably and for a long time without the need for complicated additional maintenance.
RCD, triggered to open the network, you can not immediately turn on. First you need to find the area of the problem and fix it. Only then it is permissible to return the device to working condition.
The electronic RCD is a more modern monitoring module and is equipped with sensitive microcircuits that react to any changes occurring in the network. It works even under the condition of an on-line voltage drop, since the transformer element “notices” only the difference in the difference between the current flows.
The main working body is the electronic board located inside with a special amplifier. For proper functioning, it necessarily needs power coming from an external network. If the system has a base voltage of 220 V, the protective device immediately responds to leakage and opens.
Despite a more advanced structural device, electronic protection devices are not always able to perform their functions. For example, at the time of the neutral wire in the network, they may not work
The electronic device is very sensitive and as a result of constant voltage drops can fail and lose protective functions, and apparently it will not be noticeable.
In order not to suffer because of such a situation, experts strongly recommend that users monthly check the RCD for operability by pressing the "Test" button located on the device.
How does the protection device work?
The connection of the protective module to the main electrics is always carried out after the introductory circuit breaker and electricity meter. A single-phase RCD designed for mains with a standard 220 V, has in its design 2 working terminals for zero and phase. Three-phase units are equipped with 4 terminals for 3 phases and a common zero.
Being in the activated mode, the RCD compares the parameters of incoming and outgoing currents, and calculates how many amperes goes to all electrical consumers in the room. When working correctly, these indicators do not differ from each other.
Sometimes the residual current device may work for no apparent reason. Usually, this situation is provoked by sticking of the buttons and unbalance of the device, caused by too intense operating load or condensation
The difference in performance between input and output currents clearly indicates that there is an electrical leak in the house. Sometimes it occurs due to the contact of a person with a bare wire.
The RCD fixes this situation and immediately de-energizes the controlled area of the network in order to protect the user from the potential impact of current, burns and other household injuries associated with electricity.
The lowest threshold at which the safety shutdown device operates is 30 mA. This indicator is called the level of non-release, at which a person feels a sharp current shock, but can still release an object that is under tension.
With an alternating voltage of 220 V and a frequency of 50 Hz, a current of 30 milliamperes is already felt very strongly and causes a convulsive contraction of working muscles. At such a moment, the user cannot physically unclench the fingers and throw aside the part or wire under high voltage.
All this leads to dangerous situations that threaten not only health, but also life. To prevent these troubles can only properly selected and correctly installed RCD.
All protective devices on the market for related electrical equipment and accessories today differ in type of work. AC modules are mounted in systems designed to protect household appliances from surge or slowly increasing voltage and operate with alternating current.
Products A pick up a constant pulsating current, growing in a jump-like manner, and react to it. Usually placed in homes for individual protection against drops and combustion of washing machines, televisions and dishwashers. They have a structurally complex device and are much more expensive than other elements of this class.
The best place to locate the RCD in a residential building is an area nearby with a power source. Experts recommend placing the device directly next to the total meter.
Apparatus B is not suitable for homes and other residential areas. Their field of operation is enterprises and production shops with a large number of electronic equipment.
Selective devices S and G are triggered in 1-4 seconds after the leak is fixed. Usually embedded in the network, where several protection devices are present in one power line.
Main parameters of the product selection
It is necessary to choose the RCD in strict accordance with the main performance indicators of the electrical system located in the house.
Too strong protection, far exceeding the power of all household appliances available to the owners, will not cope in the future with the task and will not be able to protect the user and housing from flammable situations because it does not fix dangerous leakage.
Purchase an RCD better with a small margin. Otherwise, the appearance in the home of any new module of household appliances will cause overload and will lead to a constant response of the protective device
A device designed to operate at relatively small elevations simply will not withstand an elementary load. In addition, it will start to work too often, thus causing a lot of inconvenience to the owners of the dwelling.
Selection by type of network voltage
The voltage of 220 V is a classic indicator relevant for single-phase networks used to supply standard consumers with electricity. Normally, the tolerance from the index is within +/- 5%.
According to these data, the voltage range of 209-231 V is considered optimal and does not exert unnecessary loads on the system and the devices connected to it.
If several electrical circuits come out of the switchboard, you need to equip each of them with a separate RCD. This will entail additional costs, but in case of problems and the device is triggered on the same line, everyone else can continue to work as usual.
To protect such a network, usually built in a small house, a simple RCD, designed for single phase network connection and minor voltage surges and correct operation with the circuit breakers already existing in the house.
Indicator power protection device must be an order of magnitude greater than the total total power of all household appliances available in residential premises.
In large houses with a large number of household appliances and the presence of specific appliances, premises providing life support, often more powerful and operationally stable three-phase are used. network 380 V.
A special protective device is used for it, which differs somewhat in configuration from the standard single-phase device. The level of the threshold of such a product is very high. It is placed in a special shield. In the shield of the RCD and machines arranged in a specific order according to the purpose and rules of selectivity.
The distributor, regardless of the height of the building, is always located at the bottom near the entrance to the house. As a rule, it is equipped with an “S” protection with a certain delay time and a leakage current indicator of 100 mA.
In order to avoid false alarms of the device, in some rooms where the wiring is outdated and has served its time, a built-in RCD socket is installed. Such a device controls the level of the current flow when activating consumer or lighting equipment and reduces the load on the system.
Electric lines on the floors, living rooms, technical rooms, kitchens and bathrooms are laid with an introductory machine. In separate rooms, where, according to the fire safety requirement, the leakage current cannot exceed 30 mA, an individual single-phase protective unit is installed.
Number of poles at the instruments
The presence of a certain number of poles for safety devices is also an important criterion for selection. Bipolar products are used only in single-phase networks where you need to connect one working phase and zero.
If the single-phase network is equipped with a grounding system, the installation of the RCD is made according to the schemes given in recommended article. It describes in detail the options and rules for connecting the protective equipment to the phase, ground and zero.
Located in conventional electrical panels, RCDs with two poles occupy two seats according to the generally accepted DIN standard. Four-pole device requires 4 places for correct operation.
In systems of three-phase type with a base voltage of 380 W, units with four active poles are used, designed to activate zero and three phases.
Throughput current level
The throughput or rated current of the RCD directly depends on the number and total power of instruments and equipment connected to the electrical network.
So that the input protection device works correctly and does not knock out the phase, when the user simultaneously activates several household appliances, this indicator should be designed for all energy-consuming modules available in house.
The most common products used in everyday life are designated as 16, 20, 25, 32, 40, 63, 80 and 100 amperes. For protective units of linear type working power is calculated based on the number of electrical products connected to each individual branch
Manufacturers for convenience of choice mark safety elements with numbers indicating the maximum size of the throughput current in amperes.
Leakage current difference
The leakage current is a certain value, upon reaching which the RCD opens the electrical circuit and stops powering the devices. This extreme threshold is called the nominal, and for various protective devices is usually 10, 30, 100, 300 and 500 Ma. How to set the selective RCD, learn from next article, the content of which we advise you to read.
A unit of 30 mA is considered optimal for small private houses. It copes well with the assigned task and turns off the line when a leak is detected that does not pose a danger to human life.
Products of lower ratings are excessively sensitive and will deactivate the power supply of devices with energy resources at the very least network fluctuations. There are others reasons for knocking out the RCD, which should know the zealous owner.
Top RCD manufacturers
The market for modern automatic equipment designed to monitor and control electrical systems is undergoing a period of active growth. The venerable manufacturers and promising newcomers are trying to offer the customer the highest quality products with good functionality.
ABB Automatic Products
The Swiss-Swedish firm ABB in this segment confidently holds the leading position for more than one year. Residual current devices manufactured at the company's production facilities are considered very reliable, durable and completely safe.
At the same time, they in all respects meet the latest requirements of the EU for equipment and accessories of this kind.
Modules of ABB concern are more expensive than similar devices of domestic production. However, experts say that all costs are fully justified, since the RCD of this brand is several times higher in all respects similar devices of other brands
In the manufacture of its devices, the company uses innovative materials and parts with unsurpassed high operational stability. The range of models is very wide and meets the needs of electrical systems of any capacity and complexity.
What offers users IEK
The company IEK is a leading domestic manufacturer and supplier of products of light and electrical products. It has been successfully operating on the Russian and post-Soviet market for more than 17 years. Creates a variety of high-quality equipment and provides a prolonged warranty on its products.
Protective disconnecting units from IEK are in great demand in Ukraine, Russia and Belarus due to a combination of optimum quality and affordable cost. Products are included in the line of budget goods and allow you to equip the security of the electrical system for reasonable money
IEK products are selling very well due to the price, which is significantly different from the cost of products of world brands.
Each device fully complies with the declared characteristics and, when properly used under the conditions described by the manufacturer, always fulfills the prescribed period.
True, customers sometimes complain that the devices have a weak plastic case that can crack or disperse in case of over-tightening with clamping screws and often hum, even when they are very small load. Nevertheless, these disadvantages have virtually no effect on the turnover of IEK, which only increases from year to year.
Nuances of products of the enterprise Contactor
Kontaktor Plant is one of the most large-scale industries engaged in the manufacture of electrical products and related parts in Russia. Since 2007, part of a group of companies that own the famous French brand Legrand. Concern specializes in the creation of lighting and electrical engineering.
Electricians and electricians very well speak about the products of the plant Contactor and call them among the highest quality, reliable and durable products of the budget of Russian brands
The peculiarity of the plant’s products is that they make it exactly the same as at European enterprises Legrand, and the cost does not exceed the price of similar devices of domestic production.
Classic installation solution
Of course, in each case, the UZO is selected taking into account the individual characteristics of the electrical system and household appliances in the living room. However, there is a universal option, suitable for most average homes.
All work on the installation of the RCD should be carried out with the power disconnected and with strict observance of basic safety rules.
In reality, the circuit looks like this: after the input automaton, the first device is the 100 mA protection device. Outgoing lines that distribute the current flow directly to the floors and rooms are protected by more sensitive and sensitive devices with a rate of 30 mA.
On the line that supplies the electrician to the devices located in rooms with high humidity levels, for example, in the bathroom, bathroom or the kitchen is placed a protection device of 10 mA with a nominal current not lower than the current of the automaton mounted in front of RCD.
What is the difference between a safety device and a “closest ally”, a differential automaton, you will learn by reading article recommended by us. In it the difficult, but very interesting subject is in detail sorted.
Conclusions and useful video on the topic
What is RCD, what is it for and how to install this device correctly in a private house:
Rules for the selection of RCDs for residential houses in terms of the differentiated current and the length of the wiring. Detailed explanation of the process from the professional master:
Installing a UZO in a private house does not require significant material investments from the owners, but it will increase safety of the electrical system, protects residents from electric shocks and burns, and real estate will protect against fires.
To make the device work conscientiously, it is better to choose a reliable product of a popular brand, and not a Chinese nameless. Save here will not succeed, but the result of the proprietary module will be several times higher than that of a cheap counterpart.
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