It is known that once a year the things around us acquire the power of speech. On Christmas Eve, in an apartment where a major overhaul had just been completed, the electricity meter suddenly started talking. Since each of us in the process of repair and reconstruction of housing is faced with the problem of electrification, it makes sense to listen to the advice and recommendations of the patriarch of the residential electrical installation
About the hybrid «Zaporozhets» and «Mercedes»
Do you know, dear ones, that in the 60s Moscow’s power grids were designed with a design load per apartment of 1000Tue, and in cities with a population of up to 1million people— 800W? As long as citizens were content with three or five forty-watt light bulbs, a weak refrigerator and an iron, if it was electric, there were no big problems. Silence and grace ended when apartment meters began to «wind up» from200 to1000kW per month. The energy consumption of simultaneously operating devices and equipment today is several times higher than the permissible load, while electrical networks in old houses are in a «primitive» state. Wires in fabric insulation and open wiring in communal apartments and pensioners’ homes— and now is not uncommon. ATthese houses retain outdated two-wire power lines, while most modern electrical appliances are designed to be connected to three-wire lines that have a neutral protective conductor. Leakage currents and short circuits in such networks— a common occurrence. That is why the number of fires and cases of electric shock to people in apartments built after the war and in the 60s, has risen sharply in recent years.
What about the owners of those «Stalinist» apartments, where there is an abundance of useful household appliances? I will not hide, even if their electrical installation is put in order, the need for forced use of electrical appliances in turn is not eliminated by this. When they are turned on at the same time, the entire entrance can remain without light.— the circuit breaker installed at the entrance to the building will work.
Surprisingly, many owners of valuable home appliances are often remarkably careless when using them. BUTin vain … I’m sure it would never occur to anyone to drive a Zaporozhets if there is a Mercedes in the garage. However, worn-out wiring, circuit breakers of an unknown manufacturer, or an unreliable electronic residual current device of the type UZO-20 in the apartments saturated with modern household appliances and lighting fixtures, wealthy people can be found very often. Believe me, this phenomenon is just as ridiculous and dangerous as driving a «new Russian» on a «Zaporozhets» at the speed of a foreign car.
It’s time to remind you that the electrical installation in the apartment— this is a set of household electrical appliances, auxiliary devices (electric meters, circuit breakers, residual current devices, timers, control devices, etc.), wires, electrical installation products (sockets, switches) designed to convert, transform, transmit and distribute energy.
What is the «root of evil» and how to deal with it?
The danger is outdated or incorrect wiring diagrams. ToFor example, the power supply scheme for a luxury apartment recommended by the State Energy Supervision Authority, unlike an ordinary dwelling, assumes the presence of separate power circuits for an electric water heater, a sauna, sockets in the bathroom, and additional socket groups in the rooms. Meanwhile, during the reconstruction of apartments, individual circuits are often connected with a “loop” (in series). This is illiterate and creates unnecessary problems. For example, it becomes impossible to turn off one of the circuits, let’s say a socket group in the kitchen, without de-energizing the entire apartment. Quite often, three-wire lines (mandatory today) are not laid from introductory shields (group, floor) to sockets and lamps. Conductors do not always have the same cross section. Zero protective and zero working conductors are erroneously connected on the shield under one terminal. Structurally, there should be two clamps, and they are connected by a jumper, then in case of «burning» (during a short circuit) of one of them, the second ensures the safety of the protection line. Not all homes have a grounding system that is done correctly and functions reliably.
Electroshock or electroshock?
Almost all modern electrical appliances, with the exception of appliances with double plastic insulation, marked with a sign (meaning «can be plugged into any socket»), are designed for connection to euro sockets with a zero protective conductor PE. ATunlike the Soviet two-wire network in Europe, and now in Russia, a three-wire network with phase, zero working and zero protective conductors has been adopted, which, in the presence of protective shutdown devices, makes the electrical installation many times safer. Do not think that the problem can be solved by simply replacing the sockets: the zero protective wire must be laid from the sockets to the switchboard itself, and this entails replacing a two-wire wire with a three-wire one. Do you want to sleep peacefully— then replace the old-style electrical wiring in the apartment. Otherwise, sooner or later it will let you down.
The electrical switchboard and the apartment shield deserve special attention. ATIn the practice of previous years, it was customary to install a switchboard, and in a number of houses and an apartment shield outside the apartment. ATin our unsafe time, it is necessary to securely lock the switchboard on the landing, and put all the circuit breakers on a new shield from inside the apartment.
What should be the housing shield? Firstly, have a strong lock. Secondly, be spacious enough to install an electricity meter, the necessary devices and automatic machines, their control and verification, third, convenient for conducting electrical work in the apartment. Fourth, look aesthetically pleasing. Quality shields are produced by ABB (Switzerland), LEGRAND (France), SPELSBERG, SHNAIDER, FG (Germany), «SVETOLYUKS» (Russia).
In an electrical installation, mounted without taking into account modern requirements, as a rule, there are no new and unmistakably selected electrical installation devices at all. ATfirst of all, these are protective shutdown devices and automatic switches that provide electrical and fire safety of a home and a person. Household RCDs that respond to leakage currents with a power of 30mA, within 0.03seconds turn off electricity when a person touches live parts. The advantage should be given to electromechanical RCDs— they can be trusted more than electronic ones. In practice, a family of domestic RCDs produced by OAO TECHNOPARK-CENTER has proven itself well (trademark «ASTRO*UZO»).
Automatic circuit breakers are triggered by short circuits in the network and protect primarily electrical equipment. ABB products are characterized by high reliability and quality, SIEMENS, HAGER (Germany), LEGRAND. High-quality circuit breakers are manufactured in St. Petersburg under the license of ABB. Household circuit breakers must be marked with the index «B» and «C» on the body.
But even «branded» devices do not work «in good faith» if they are not installed according to the optimal scheme. The reason is that even competent electrical publications sometimes give mutually exclusive recommendations for their installation and operation. For example, it is proposed to install an RCD only at the entrance to the apartment. Imagine that your electric bell has deteriorated (it began to spark, which means that leakage currents arose). ATIn this case, the protective device will turn off the electricity in the entire apartment, and in your absence, the refrigerator will defrost and the automation dependent on the network will be deprogrammed. Therefore, there should be several RCDs in a modern apartment, while it is recommended to install them both at the entrance to the apartment and on individual electrical receivers, such as a water heater, washing machine, etc. If a separate electrical device is faulty, the device will turn off part of the circuit, while the electrical installation as a whole will remain in working order. RCDs can be stationary in the form of a separate device (on a shield, in combination with a socket) and built into an electrical appliance (jacuzzi) or into its plug (hairdryer, mixer, vacuum cleaner). According to the old rules, sockets in bathrooms were installed only using an isolating transformer, the power of which only allowed electric shavers to be included in them. Now, according to the new rules for performing electrical work, it is allowed to use electrical outlets without an isolating transformer, but equipped with an RCD for rooms with high humidity. Protective devices simplify troubleshooting in the electrical installation of the apartment. How this is done in practice, we will describe in a separate article. The cost of electromechanical RCDs is $30-50, automatic protection— $5-15, housing shields— $17-30.
In most cases, hidden wiring is laid in the apartments. In case of mechanical and other damage, the wire is removed from the channel in the wall and a new one is pulled in its place. If the old wire breaks or gets stuck in the channel, then you have to chisel the wall. Thinking about the future, it is important to competently and efficiently perform electrical work, using wires, junction and branch boxes, protective PVC pipes, and high quality connecting terminals. They prolong the life of the wires and make it easy to replace them. Connoisseurs of household electrical engineering speak well of protected insulated copper wires of domestic production (see N3 per1998g.), installation, connecting and branching boxes of KAISER (Germany), SPELSBERG, connecting terminals WAGO (Germany) and TOWER (England).
Today, plastic cable channels are becoming increasingly popular, with which you can easily lay open wiring in any room. However, architects and designers are by no means ardent supporters of their widespread use. FROMFrom an aesthetic point of view, cable channels are not always and everywhere acceptable. ATto a large extent they— an element of office design, although they are also installed in apartments. The German company REHAU offers plinth cable channels, in which, along with electrical wires, plastic pipes for hot and cold water supply are laid in the insulated part of the plinth. The use of REHAU plastic plinths, LEGRAND, THORSMAN (Norway) cable channels makes wiring more accessible for diagnostics and preventive maintenance, and, if necessary, allows you to make changes to the electrical installation diagram. If their appearance does not go against your ideas about aesthetics, feel free to use them for wiring inside the apartment.
Candidate of technical sciences V.TO.Monakov comments on the differences between grounding systems. The classification of their types is presented in GOST R50571 «Electrical installations of buildings», p.312.2.
There are the following types of grounding systems: TN-C, TN-S, TN-C-S, TT, IT.
The first letter in the designation determines the nature of the grounding of the power source: T— direct connection of the neutral of the power supply to the ground; I— all current-carrying parts are isolated from the ground.
The second letter determines the nature of the grounding of the open conductive parts of the electrical installation of the building: T— direct connection of the open conductive parts of the electrical installation of the building with the ground, regardless of the nature of the connection with the power source; N— direct connection of the open conductive parts of the electrical installation of the building with the grounding point of the power source.
Following for N letters define the nature of this connection— functional method of arranging the zero protective and zero working conductors: S— functions of zero protective (PE) and zero worker (N) conductors are provided with separate conductors; FROM— the functions of the zero protective and zero working conductors are provided by one common conductor (PEN).
Until now, Russia has been using the system TN-Cin which the open conductive parts of the electrical installation (cases, casings of electrical equipment) are connected to the grounded neutral of the source by the combined zero protective and working conductor (PEN)— «nullified». This system is relatively simple and cheap. However, it does not provide the necessary level of electrical safety.
In system TN-Sthe most widespread in Europe, all open conductive parts of the electrical installation of the building are connected by a separate zero protective conductor (PE) directly with the grounded source neutral.
In system TN-C-S in the input device of a specific electrical installation, a combined zero protective and working conductor (PEN) divided by zero guard (PE) and working zero (N) conductors. At the same time, in this electrical installation, the zero protective conductor (PE) is connected to all conductive open parts and can be repeatedly grounded, while the working neutral conductor (N) must not be connected to earth. The most promising for our country is the system TN-C-Swhich allows to ensure a high level of electrical safety in electrical installations without their radical reconstruction.
Important note! In grounding systems TN-S and TN-C-S electrical safety of the consumer is ensured not by the systems themselves, but by the possibility of using residual current devices (RCDs) in them— the most modern and effective electrical protective equipment.
Miser pays twice
Many owners of apartments being reconstructed, attracted by the appearance of wiring accessories, purchase them without paying attention to quality. On the shelves of shops there are hundreds of varieties of switches, sockets and other products, different in design and construction. Outwardly, a completely identical socket manufactured by the company SIEMENS can cost three to four times more than Turkish. In all respects, the exclusive socket of the German company JUNG costs even more. The difficulty of the buyer, who does not know what to give preference to, is understandable. ATelectrical engineering, the price, as a rule, corresponds to the quality of the goods. ToFor example, if there is incomplete contact between the prongs of the plug and the socket terminals, sparking occurs and heat is generated. High-quality imported plastic conducts heat well and transfers it to the mass of the wall, as a result of which the socket does not overheat and does not fail. By purchasing a cheap Polish or Belarusian-made socket, you increase the risk of fire, especially if it includes an energy-intensive electrical appliance, such as a grill or boiler. Toto thatit is not always possible to be sure that the «left» sockets and switches are designed for the current strength indicated on their marking. The same can be said about electrical wires and cables. Not only is the cross section of the conductor in the home electrical circuit often much less than required, the quality of the insulation of the wires leaves much to be desired. ATnetworks with wires of Polish and Turkish production, the percentage of short circuits is higher than in domestic ones. You should be aware that in addition to the quality certificate, each type of wire (as well as RCDs) must have a certificate of compliance with fire safety standards.
Just like laser discs and sneakers, Chinese, Polish, Turkish manufacturers of non-certified electrical goods copy protection devices and circuit breakers from well-known companies. It can be quite difficult to distinguish a fake from the original. Therefore, buy products of this kind in specialized stores or trading houses, or (if you are planning a comprehensive repair) entrust this business to a reliable company that has a license and a positive reputation.
Suppose you managed to independently bring the electrical installation to perfection in the apartment. However, you do not have the right to officially operate it. The point is that with1995year, by order of the Ministry of Fuel and Energy, all electrical installations in apartments that differ from standard design documentation must be certified, to which local regulatory authorities are now paying special attention (see our magazine N1 per2000G.). Therefore, before proceeding with the reconstruction of the electrical installation, you are obliged to coordinate the project, the development of which can only be entrusted to an organization that has the appropriate license, with the local Gosenergonadzor authority. After completing the electrical work and testing, you should receive a certificate from one of the accredited laboratories. Wouldn’t it be easier, saving time and nerves, to turn to professionals who will perform design and electrical work on a turnkey basis and hand you the document you are looking for?
So, the power supply of your apartment is made in accordance with the rules for the installation of electrical installations, the regulatory authorities have no complaints. The electric chic of the apartment is shocking even for connoisseurs and connoisseurs. They envy you and try to imitate you. Success, however, is momentary, and ideas about comfort with the introduction of scientific and technical innovations change almost daily. It is possible that tomorrow you will want to put into action another novelty of electrical engineering in your apartment. Is your electrical installation ready for the next replenishment? And is there a limit to the saturation of the dwelling with useful mechanisms and equipment? It makes sense to think about these problems when starting to design an electrical installation, we will talk about this more than once on the pages of our magazine.