Each electrical installation has mechanisms for the input and distribution of electricity. Often, these devices are combined in one input-distribution device, in the form of a shield or cabinet, consisting of several panels. As a rule, these are introductory, distribution and ATS panels. This is where the various names of this device come from: VRShch, MSB, VU. Depending on the operating conditions at the facility, the task of changing the input switchgear inevitably arises.

With timely maintenance, the replacement of parts of the ASU is carried out in stages, according to the failure of the equipment, but even with this approach it is not possible to avoid a one-time overhaul. This is due to the aging of the insulation of cables and wires, as well as the necessary replacement of the ASU circuit. After 20-25 years of operation, ASU becomes so obsolete that it is easier to replace old equipment than to constantly repair it.

It makes no sense to order an analogue of the original ASU, since the original circuit and the loads themselves have changed over a long period of operation. Therefore, the first thing to start with is to draw an electrical installation diagram with load calculations. Already having the actual scheme in hand, you can order the design and manufacture of a new one, taking into account all the loads of the ASU.

Before installing a new ASU, it is necessary to work out a temporary power supply scheme. In the case of a large capacity of the electrical installation and if several work shifts are required to replace the ASU, temporary power supply schemes are activated using a diesel generator or other sources. Such cases occur when working on consumers of the first category of reliability, which include hospitals and enterprises with a continuous cycle. In fact, if there is no need for a backup circuit, then the replacement of the ASU is carried out on weekends or at night. To work on the ASU, it is necessary to de-energize by turning off the automatic switch or knife switch. Often, turning off the power is possible only in the TS. If the substation is on the balance sheet of the electric grid company, then the planned shutdown is coordinated in the operating area to which the transformer substation belongs.

After the installation of new equipment at the input, the installation of electricity metering devices takes place, which are sealed by representatives of Energosbyt. Prior to this, the scheme of the input switchgear is coordinated in Energosbyt. Along with this, the numbers of new meters are entered into the energy supply agreement. Replacing an ASU is a lengthy and complex procedure of increased danger, and in cases of unplanned downtime, it is possible to stop the entire activity of the enterprise. Trust the replacement of ASU to professional contractors.

27.05.2014

Install input distribution device necessary only after the location of the shield has been determined. Most often, the shields are located near the place where the designers indicated the exit point of the cables from the foundation of the structure through reinforced holes or from a specially equipped pit. After choosing a location, you can proceed directly to the installation of the shield.

To carry out this operation, you will need: a screwdriver equipped with a 10 mm metal drill, a hammer drill with a 10 mm drill installed, a tape measure, electrical tape, a set of key heads, a grinder or metal scissors, a level, an ordinary clerical or better dielectric knife, a set of dies with a press, as well as a marker.

This type is fixed on the walls at a height of 30 centimeters from the floor. This is required in order to qualitatively and smoothly start the cable. In this case, aluminum armored cables are usually used. To mount the cabinet, you can use silicate bricks as a temporary stand for it. Next, you should install the shield itself on them. It must be leaned against the wall on which the fixing will be carried out.

Now you can drill holes in the wall for the anchor. Before this, it is necessary to make four holes in the shield body. They should be such that the anchor bolt simply enters it. The marking of the holes obtained must be transferred to the wall by circling them with a marker. Thus, the markup is completed. Now you can remove the shield, put it aside, and drill holes with a puncher with a 10 millimeter drill.

After drilling holes and hammering dowels into them, it is necessary to reinstall the shield in its place. In this case, it is necessary to align the holes in the shield body with the holes in the wall. To tighten the anchor bolt, it is better to use a ratchet wrench. It is best to use bolts from the market leader - HILTI. On this, the process of mounting the shield on a concrete wall can be considered completed.

Then you can move on to the next step! This is. She is quite labor intensive. Moreover, serious knowledge and remarkable experience are required. You should start by cutting the cables. To do this, use a prepared dielectric or ordinary clerical knife. Along it is necessary to cut the cable insulation and remove. Before this, it is necessary to measure in such a way that the stripped part of it is not visible from the bottom of the shield. Simply put, the cable must be wound into the shield in a sheath, and already go inside without it. Since an armored cable is used, it is necessary to wind up the armor without cutting it off. After all, it will sit on the ground bus.

Next, you need to prepare the cable, or rather its ends, for crimping using aluminum lugs. It is necessary to strip the ends of the cables along a length of 3-4 cm. The end of the cable, which is exposed, must be completely immersed in the cavity of the tip.

After crimping all cable lugs, it is necessary to wrap the part of the lugs that is clamped with electrical tape. Next, the cables are led into the shield and fixed on zero and phase buses. After the cables are inserted, they are fixed with a nylon tie at the bottom of the shield. The latter is equipped with a special bar for these purposes. In order to carry out landing phase wires, you need to use special small tires on the machines below.

The neutral wire is fixed on a large bus at the bottom of the shield. Grounding is fixed on the lower bus. It is necessary to plant phase cables in the sequence white, black, red. A white core must be planted on a yellow tire, black on a green one, red on a red one. It is important that the lugs are firmly fixed on the tire with nuts. After all, it depends on whether it will work efficiently and smoothly electrical equipment. Cables must not be interchanged with phases in the substation.

Next, you can begin to fix the zero cables to the zero bus. The process is similar. The cables are secured with nuts and washers. The aluminum winding of the cable is fixed to the ground bus in the same way. It must first be drilled with a suitable drill.

Now it remains only to mount two electricity meters, and the process of mounting on the wall and assembling the ASU can be considered completed.

The input distribution device (ASU) is designed for safe reception, reliable distribution, accurate metering of electrical energy, protection of outgoing lines from overloads and short circuits, operational switching in order to control the state of electrical equipment. The installation of the ASU must be carried out by qualified personnel in accordance with a previously developed and approved project. When installing the ASU, one should be guided by the requirements of the PUE and other regulatory and technical documents.

Price for

from 35 000 rub.

Features of choosing a place for mounting ASU

Installation of the input-distributing device is carried out in special rooms that are designed for these purposes. The ambient air temperature range in the room should be between +5 0 C and +40 0 C. When installing ASU outside specialized premises, a whole list of conditions must be observed:

1. It is forbidden to install input distribution devices closer than 100 centimeters from pipelines for heating, hot and cold water supply, sewerage and gas supply.
2. Distribution devices must be covered with casings or installed in boxes.
3. The place for mounting the input-distribution device must be accessible around the clock for electrical personnel.

The price for installing an ASU outside the electrical room and inside it may differ due to the need for additional laying of supply wires. If there is a risk of flooding of the premises with the installed input-distribution device, it is necessary to carry out installation above the flood mark. The room for the installation of the ASU must have ventilation and electric lighting. The doors of the premises where the ASU is installed should only open outwards.

Requirements for the installation of input distribution devices

When supplying power from an overhead power line, it is necessary to provide for the installation of surge arresters at the input. The input of supply cables is carried out from below as standard, but the customer has the opportunity to make changes to the project and carry out the cable entry from above. At the points of connection of cables and wires, it is necessary to leave a margin that will ensure that there are no problems when reconnecting or transferring the ASU. Installation of the ASU must be carried out by qualified personnel who will ensure the competent connection of all wires, cables, switching and measuring equipment. Upon completion of the installation of input distribution devices, it is necessary to carry out electrical measurements that will help identify errors or factory defects in the equipment.

ASP installation cost

The price for installation of ASU depends on the complexity of the installed electrical equipment, which is determined by the following criteria:

• number of inputs;
• availability of commercial metering units;
• number of outgoing lines;
• availability of control and measuring devices;
• availability of relay protection devices;
• the presence of ATS and other types of automation.

The price for the installation of ASU, to a large extent depends on the design decisions made. When drawing up an estimate for the installation of an ASU, be sure to take into account all the additional equipment that is present in the electrical panel.

Our company will perform professional installation of ASP, the price of which is calculated individually for each object. The estimate for the installation of the ASU is compiled by our specialists based on the design decisions made and the local features of the customer's facility. We guarantee that our ASU installation rates will be one of the most affordable in the region.

Portfolio

The main activity of the Signal company is the professional development of projects, production, installation of ASU, as well as other switchboard equipment.Our employees have specialized education, have the necessary competencies for high-quality work.

Functional blocks of ASU devices - input, AVR, accounting, distribution, lighting control - allow you to create a workable and fault-free network.

Instruments

The preparatory stage of installation work involves the design of internal power supply and the selection of the necessary installation of ASU tools.

P a puncher with a drill will help to drill holes. Tape measure and level - measure the footage and installation location. To work with metal, you will need a grinder, a drill. You will need a set of wrench heads, a screwdriver, a cable or clerical knife, a set of dies, adhesive tape, a press and a marker.

Installation steps

Choice of installation location. The first stage of electrical installation work is to determine the location of the ASU according to the requirements of the PUE and other standards. The orientation becomes the point of entry of the power cable, marked in the project documentation.

The installation site must be accessible for equipment maintenance, located above the possible flood level. It is forbidden to place ASU under bathrooms, toilets.

Attaching the shield to the wall. The installation of the ASU is carried out taking into account the standard distances. The cabinet is placed at a height of 30 cm from the floor: space will be needed for laying cable chains. Installation is carried out at a distance of at least 1 m from gas meters, sewer pipes, heating, water supply, gas pipelines.

The ASU is fastened with anchor bolts and dowels. Products are installed in the holes prepared in the device and the wall. The anchors are tightened with a ratchet.

ASU assembly. The ends of the cable are separated with a knife. Outside ASU- the conductor must remain in the protective sheath. Cable armor is connected to the main ground bus. The ends of the cable are exposed, immersed in the cavity of the tip. After crimping, the clamped part is wrapped with adhesive tape.

The conductors are brought inside the cabinet and fixed on the corresponding tires, zero and phase. Fixation is carried out with a nylon tie. The conductor ends are fixed with washers and nuts.

Testing. The final stage of installation is a series of measurements to eliminate violations of standards or identify inaccuracies. Installation quality control begins with a visual inspection of the electrical installation. Special instruments are used to measure grounding and insulation resistance. The quality of windings of devices, insulating sheaths of wires, cables is checked.

Installation cost

The complexity of the project being implemented, the type and price of the input distribution device chosen by the customer, the urgency of installation, the tools used, the wall material, cramped working conditions - all parameters affect the installation cost.

The Signal company offers favorable terms of cooperation for customers and attractive prices due to the use of inexpensive components and materials. approximate cost electro installation work is 20% of the price of the electrical device.

Employees of our company advise clients on the issues of electrical installation of input distribution devices and prices remotely. You can ask your questions by mail.

ASU or input-distribution devices are widely used when performing electrical work. Their main task is the reception and subsequent distribution of electrical energy between individual consumers. ASUs provide reliable protection of all installed instruments and equipment from the effects of short circuits and emergency overloads.

ASU in electrics:

The control devices available in each input-distributing device allow you to accurately take into account the consumption of electricity, exercise control over the correct distribution of the load in the networks. Electric meters can be installed both general and individual, designed for individual consumers. In general, for the normal operation of most ASUs, a mains voltage is required in the range from 220 to 380 volts. Frequency alternating current can range from 50 to 60 hertz. All devices are solidly grounded.

Scope of ASU

Input-distribution devices are widely used, they are suitable for installation on any structures where the presence of electrical equipment is provided. ASUs are installed at almost all industrial and production facilities, as well as in residential and public buildings.

With the help of ASU, electricity is supplied to houses with any configuration and number of floors. The building may include groups of premises - offices, business centers, enterprises consumer services and catering. All necessary design parameters and technical requirements to the configuration of input-distribution devices are determined in the project documentation.

When assembling the ASU, all customer requirements are observed. This allows us to fully ensure the further reliable and trouble-free operation of electrical networks.

Complete set of input-distributing devices

All ASUs are made as a one-sided panel, placed closed, in a protective steel box. In the future, this panel is used for installation of automatic electrical devices for control, metering and distribution of electricity. The designs of input-distribution devices may include one, two or more panels. In some cases, they are assembled in sections. For complete assembly ASU there is a floor or suspended version.

At the request of the customer, the device can be included Various types circuit breakers, electronic or capable of taking into account active and. Additionally, test boxes, instrumentation and other devices are installed.

Existing standards assume the resistance of input-distributing devices to surge current during short circuits up to 20 kA. The rated insulation protection is 1000 volts. In addition, international protection parameters must be observed in case of contact with live parts of the device. ASU equipment is carried out taking into account local climatic conditions.

The principle of operation of the ASU

The input of the main power cable is made directly to the introductory machine of the device. calculated in advance and reflected in the project or terms of reference. The introductory circuit breaker protects electrical wiring during emergency situations. With its help, it is possible to deliberately turn off the power for work on maintenance networks. In some ASU designs, the introductory machine can be replaced with a special disconnector.

After the introductory machine, arresters are installed. Here the phase conductors and the protective PE bus are connected. When impulse overloads occur, the arresters are triggered, the phase voltage hits the PE bus and the final operation of the ASU protection.

The final distribution of the power supply, in accordance with the groups of wires, is carried out using circuit breakers with different ratings. Each consumer group is connected to a separate circuit breaker. As additional protective measures, if necessary, RCDs are installed.

The installation of distribution machines must ensure an even distribution of the load between all phases. When calculating the automata for each phase, the demand coefficient, which determines the probability of the maximum load of electrical networks, must be taken into account.

The use of ASU in residential and public buildings

In public buildings, residential buildings with elevated number of storeys, as well as in small manufacturing enterprises, the use of input-distribution devices, which are shields, in which one-sided or two-sided service can be performed, has come into practice.

The kit of each such device includes input and distribution panels, or cabinets manufactured in the factory. In large electrical installation organizations, very often their own ASU designs are developed and used, taking into account the individual characteristics of an object.

Input panels are equipped with equipment designed to operate at rated currents of 250, 400 and 630 amperes. In panels rated for 250 A, fuses PN-2-250 are installed, as well as a knife switch or knife switch. In panels for 400 and 630 A, the same protective and disconnecting devices are installed, in accordance with the rated current.

Distribution panels are manufactured in several variants. In one of them, outgoing lines are equipped with circuit breakers. Other types of panels have automation that allows you to control the lighting on the stairs and in the corridors. Some panels have accounting departments. In addition to automatic machines, distribution panels are equipped with magnetic starters, intermediate relays and batch switches.

In the process of assembling and completing the ASU, the location of the input and distribution panels is carried out next to each other. The production of these elements is carried out in the form of separate panels, in which all the necessary equipment and devices are pre-mounted. Connecting conductors are provided between the panels. Introductory and distribution panels have a large number, thanks to which it is possible to layout any input-distribution device based on the electrical diagrams of a particular building.

The use of ASU in industry and production

Production and industrial enterprises differ in the consumption of quite significant capacities. At these facilities, with high energy consumption, special designs of input and distribution panels and cabinets are installed. As a rule, these models are included in the SHO-70 series. In addition to enterprises, such devices are in switchgears of substations, with a voltage of 0.4 kilovolts.

By their design, these devices involve one-way or two-way service. All panels provide for the installation of fuse switches or circuit breakers.

With one-sided maintenance, the installation of panels in shields is carried out right next to the wall. They are serviced from the front. Panels intended for double-sided maintenance are located freely or separately from the wall, at a distance of at least 80 cm. Single-sided shields do not require large areas for their installation and further maintenance and are more economical. However, devices with two-way maintenance are much more convenient during their operation.

Input-distribution devices are not only panel types. For their assembly, separate blocks in the form of fuses, switches, circuit breakers, meters and other electronic equipment can be used.

The premises where the ASU is installed should be located in a convenient place, accessible only to service personnel. These premises received another name for switchboard rooms, with access restriction for unauthorized persons.

The simplest scheme for automatic transfer of a reserve, and a budget ASU

Hello, dear readers of the Electrician's Notes website.

In past articles, I told you in detail about how to do it correctly.

Today's article will be devoted to the topic of the introductory switchgear, or in short - ASU. This phrase has been repeatedly mentioned in my previous articles.

Let's talk about this in more detail so that you can imagine what it is.

And I also want to add that in this article we will talk about introductory switchgear (ASU) of residential premises and buildings (administrative, domestic and public).

What is an input switchgear?

Introductory switchgear is a set of protection devices (, fuses, etc.), (ammeters, voltmeters,), (knife switches, disconnectors, current transformers, busbars, etc.) and building structures, which are installed at the entrance to the residential premises, or the building, including, among other things, protection devices and electricity meters for outgoing lines.

In short, the introductory switchgear is called the ASU.

Here is an example of ASU-0.4 (kV) of a residential apartment building, which we installed at.

In our own words, we can say that the ASU is an introductory switchgear that supplies electricity to the entire building. This may be a residential apartment building, a detached office building, or an ordinary private house or cottage.

As you can see, in the photo above it is fully observed, which I advise you not to neglect when performing installation work.

Place of installation of the input switchgear

The installation location of the input switchgear (ASU) is determined by the project. It is also possible that several ASUs can be located in the building at once.

According to the PUE, clause 7.1.30, the ASU should be installed in specially designed rooms with an ambient temperature of at least +5 o C.

Most often, in residential apartment buildings, a basement is used for these purposes.

Only trained service personnel have the right to enter the premises of the ASU, i.e. (PUE, clause 7.1.28).

If there is a risk of flooding of the ASU premises, then it is necessary to provide for its installation above the flood mark.

The cabinet of the inlet switchgear must be installed in an accessible and easily maintained place, where there is electric lighting and natural air ventilation. The cabinet must have a degree of protection IP31 and higher, and be located at a distance of at least 1 (m) from the following communications:

hot water supply

cold water supply

heating

sewerage

gas pipeline

The doors of the premises where the ASU is installed should only open outwards (PUE, clause 7.1.29).

Requirements for the VRU

If the input switchgear (ASU) is powered from overhead line(VL) power transmission, then it must be installed in it.

From the definition of the concept of ASU (PUE, clause 7.1.24), it follows that protection devices (automatic devices, fuses, RCDs, difavtomatov) must be installed on all incoming and outgoing lines.

Previously, residential apartment buildings were equipped with introductory switchgears of large sizes and dimensions. Their condition at the moment leaves much to be desired, as well as the entire housing stock of the Khrushchev and Stalinist buildings.

Let me give you some pictures as an example. technical condition ASU of residential buildings made during major repairs by our forces.

The simplest and most common inlet cabinet, consisting of a three-pole inlet switch, and ceramic fuses with quartz sand on outgoing lines.

And this introductory cabinet is in disrepair. And as soon as he finalized to the cherished day of his replacement? Outgoing lines are protected by old glass fuses with sand.

In this VRU-0.4 (kV), the power lines are protected by similar glass fuses, and the lighting circuits are protected by ceramic cork fuses (plugs) of the PRS type.

Here are photos after the completion of an overhaul of the electrical wiring of one of the residential buildings, which included the following:

• replacement of the input switchgear (ASU) with protection devices, current transformers and other switching devices
• replacement or mines
• replacement of introductory electric meters, as well as electric meters for consumers (at their request)
• translation of the old
• installation (including installation and)

P.S. On this article I conclude. If you have questions on this topic, then ask them in the comments. If you liked my article, then share it on social networks, and also subscribe to new articles.

119 comments on the entry “Introductory switchgear (ASU)”

I have met such cabinets in my lifetime, now I can imagine what it is. Helpful information for a professional and a beginner in your business.

Now I know what an input switchgear is, where and how to install it. The information is useful and necessary. Thank you, Dmitry!

Somehow it is not normal when the power cables block the terminal block of the meter

Dmitry, with your help we are already becoming cool, no, not electricians, but we can definitely be assistants. Thank you!

Thank you for your attention and support!!!

The fourth photo from the bottom, on the left side - what is the exact name of this old block with a knife switch and is it really possible to find it now?

Now this one is not for sale. Only analogues.

Unfortunately, everything is so clear. But what is behind the steel casing? The device of the cutter itself? And there are also two knife switches located side by side, connected crosswise.
I would very much like to take a closer look at the structure and purpose of these parts of the ASU. Thanks

And what are the analogues? I want it to be true to size...

I work as an electrician in Portugal. No offense, Portugal is not Germany, but these are very far away in terms of the quality of materials, the execution leaves much to be desired (the wires intersect, laid somehow, here for such work on hand). Why not unify the standards? A.B.C=L1,L2,L3:U,V,W.brown,black,grey? With uv.

If there is voltage in the lie, I can remove and install protection devices for outgoing lines if I need to connect to one of them

Marat, do you mean group (line) fuses? If yes, then remove the fuse and connect. Then put the fuse back in and you're done.

And if there is no basement, then where can you install an ASP?

Natalya, the article also says that ASUs should be installed in specially designed rooms with an ambient temperature of at least +5 oС. This room is defined by the project.

Please tell us more about reversible knife switches. I join the request of Victor.

But I just don’t see the insulators on the outgoing phase buses?

Valentin, in which photo do you not see the insulators?

Are the tires in ASU made of aluminum? When connecting to group fuses, do I need to use ferrules? Bus N and bus PE seem to be connected in two places? And I heard: an automatic device is installed to the arresters, so if the arrester is triggered, the automatic device turns off consumer groups. What kind of automatic characteristic is this? The input of group lines is made in a corrugation not in a pipe, but what about protection against rats and mice? How is the lighting in the ASU 220 cabinet taken from the input cable? For the sake of interest: is there a magnetic starter on the old ASU? What for?

Thank you very much, very informative. In my house (5th floor) under my apartment there is an ASU, which hums very strongly, there was no such hum before. Please answer what it is connected with and what anti-noise measures can be taken.

Elena, contact the management company about this. ASU should not make a hum. The hum is emitted by electromagnetic devices such as transformers, chokes, etc. Perhaps the electricians installed something additionally in the ASU room, which began to make a hum.

Tell Dmitry, the figure shows an ASU with a meter connected through current transformers, so the PE and N buses are connected together, and if the meter is directly connected, then the PE and N buses are not connected, i.e. The PEN conductor comes to the GZSH, and the N conductor is taken from the GZSH and goes to the meter, and already from the meter to the N bus.

When the building is powered by the TN-C system and its further transition to the TN-C-S system, the PE and N buses are connected to each other in the ASU. The PE bus is re-grounded. Read an article about and. Read about the meter connection schemes in the "Electricity Metering" section.

In the article Electric meter connection diagram - PE bus and N bus are not connected. I understand that the diagram does not show an introductory counter (in the ASU). I wanted to see how the direct connection counter is connected to the ASU.

I would like to continue this topic in the future. ASU for 2 inputs, ATS, etc.

Yes, Dmitry, it is planned. I am very familiar with ATS, especially ATS in electrical installations 10 (kV).

The article about AVR is very interesting

Good afternoon!! Please answer the question: Can I refuse to install an introductory machine that is installed in front of the electric meter??

Hello! Tell me why it happened: I changed the switchboard in Khrushchev (4 entrances) - put a 3-phase switch, automatic machines instead of inserts, new aluminum tires. All the wiring is old aluminum, the wires are connected to zero - through bolts with an M6 nut with enlarged washers, on a knife switch with shear bolts. I handed everything out from the heart.

Sergey, you need to see how the installation is done. A voltage surge can occur during switching overvoltages during the closing of circuit breakers, but these are milliseconds and the lamps should not burn out. Tell me what happened next. Have the ASU already been put into operation?

The shield was put into operation and no longer turned off (people began to grumble about the shutdown for 2 days). The damage was quickly revealed - it turned out to be not large - several thousand rubles (compared to the amount of work according to the estimate) and it was reimbursed. But As an electrician, this moment is unpleasant for me. I have doubts about the connections of old aluminum wires in interfloor shields, solder boxes.
In fact, I didn’t invent anything new in the connection diagram - I replaced the ancient knife switch with knives welded to death and pads with cylindrical fuses for 100 (!) A (I wrote above that the inserts are a mistake). And half of the fuses were with bugs!
How I did it: 1) they turned off the power in the local TP - I demolished the old shield, signing the wires along the phases-entrances. 2) quickly connected the switch and restored power to the house. 3) then calmly assembled all the stuffing of the cabinet: machine guns, tires. 4) connected the phase busbars to the automata (63A) under voltage and then turned them on, as quickly as he could, in the driveway and in phases.

I absolutely agree with Dmitry - transient processes in electric circuits take milliseconds and nothing should burn. But a bad contact or zero burnout in a three-phase four-wire network leads precisely to these results -
remember the vector diagram. Quite possibly this is your case.

Tell me please. Here my father has a private house that is powered by overhead lines. But in the basement there is just a small closet (where the counter, ouzo and automatic machines) turns out this is not an ASU? After all, there are no overvoltage limiters there. And it turns out there in the REN cabinet the conductor was divided into PE and H, because at home all the euro sockets. Is it correct? and whether the PE should be re-grounded and in what way

please tell me, are there any standard distances not only from communications, but maybe from walls or passages?

It’s unrealistic to find an understanding electrician. Some are French, that is, juliennes. A good landmark is cozy only in prices. Demand creates supply along the curve -B, C, D. The abbreviation Uzip or ops and how they differ leads electricians to a state of shock. I have nowhere to get clear, specific diagrams and explanations, what I can order in those organizations where you send us. As a result, without any thunderstorm, household appliances and silence burn in all the apartments of the multi-kv house. A house, an apartment, a private house. Before this, the light turns on, the socket works, money for the barrel.

Hello. On the building (1.5 sq.m) power consumption is 40 kW.
According to the formula P / (1.73 * 380 * c0s0.9) \u003d 68A. I pull vvgng 5 * 16 (do you need it in a corrugated or metal hose? 20m on the street) from a mains section of 70 meters along a perflot. Will the length of the “force” affect my calculations? To protect the wire right away
at the entrance to the ShRUV to the meter (direct connection to 100A?) put a 3- or 4-pole machine 63A on a din rail? There is no project, there is no energy. The authorities are not at all in the subject. Your pipe)

A corrugation or a metal hose is required for additional mechanical protection of the cable. If you think it's necessary, then use it. Personally, I would do it along the street in corrugation, and inside the building on trays without it. The cable is correct. Directly in front of the counter, set the machine to 63 (A) - this is.

Thanks Dmitry, everything is very informative, but I would like to know how meters should be connected in the ASU in an apartment building with two entrances? We have a big one. As our electrician says, we have three meters, one for the elevator, one for the right wing of two entrances and the other for the left wing of two entrances. The left wing is three one room apartments and lighting of the entrance and the right wing two apartments one and two rooms and lighting of the corridor. I have a question for you, can I connect in this way or should one meter be for apartments and the other for lighting corridors, padval and attic. Please tell me what to refer to so that everything is correctly done. Thank you very much in advance. Alexei.

Alexey, everything is being done according to the project, which is approved by the energy supply organization. But I will say that there are no special requirements here, it all depends on the ASU schemes and loads. In residential buildings, most often we installed one PU for the entire house. Sometimes it was necessary to install a separate launcher on the elevators, but this is again according to the project.

Hello Dmitry! The article is gorgeous, thank you! Please help: in an apartment building, in the basement there is an ASU, residents demand access there, as they are often “knocked out”.

Access to the premises of the ASU, as well as to other electrical premises, is allowed to persons who have at least group 2 for electrical safety, accompanied by a person with group 3. Well, with group 3 alone. strangers in the shield room.

Hello Dmitry, advise what to do.
We electrify a new house under construction for 8 apartments. According to the approved project, the ASU is located on the wall of the house, which means that clause 7.1.30 of the EMP is not fulfilled (The temperature of the room should not be lower than + 5 ° C.). Moreover, according to the project, the GZSH is located outside the ASU, below it and without a protective casing. That is, literally with the nuts out. The power engineer who oversees the construction has one answer - do it according to the project. How to be?

Question Why starter? What does it turn on and off. In the photo where the old lie is, where on the left there is a knife switch in the closet, and on the right there are cork fuses. Thank you.

Albert, this starter is necessary for automatic start outdoor lighting. A photorelay is installed on the facade of the house, which controls the coil of this starter. Here is a similar one.

Thank you! I thought it was some kind of ventilation or smoke removal. I saw a similar lie in a Stalinist house in one entrance.

Hello! I don’t understand, why do old-style ASUs use current transformers? Did you say for electricity metering? How does this happen?

And you can throw out the schematic of the new ASU? Thank you.

Hello! Help to understand the situation. I have no light in the entrance to the ASU room, as well as front door to this room. I turned to the management company to at least make the light. There is a switch on the wall and wires sticking out in place of the lamp. But he received a sharply negative reaction from local electricians and their power engineers. They say that the light is not needed there, they say you will climb in the cabinets. If they work there, they will connect in the distribution cabinets themselves or use flashlights. And they say the tenants have nothing to poke their nose into these matters. Moreover, the power engineer began to say that according to the design of the house, there is no light, although there are wires and a switch. In this room without light, there is only rubbish, homeless people have arranged a couch, small children play hide and seek. Well, at least he made them close the cabinets with a key, otherwise they were open. After all, children could easily climb up there. He brought them paragraph 7.1.30 of the EIC that there should be light in the room. But they don't care. Please tell me how to oblige the power engineer and his electricians to make lighting. Where can I complain in such cases (to the energy supervision)?

Oleg, you never know what they say. In the PUE, clause 7.1.28 it is clearly stated that the ASU and MSB should be installed in switchboard rooms accessible only to service personnel. In the PUE, clause 7.1.29. also mentions the doors of electrical rooms, which should open outwards. A In PUE, clause 7.1.30. it is said that the premises in which the ASU and MSB are installed must have natural ventilation and electric lighting.

Thus, the doors of the ASU must be locked from unauthorized persons, including residents, and have lighting. Please contact the energy department and explain the situation to them.

Hello. I am new to design and have a question. What switching devices are recommended to be installed on the outgoing lines in the ASP?
This is not prescribed in the PUE, but no matter how many reads, fuses are installed everywhere. I would like to understand what and why we install.

As you can see, PE aluminum bus is used. According to PUE 1.7.119, the PE bus must be copper or, in extreme cases, steel

Dmitry, good day! In my and neighboring apartment buildings (16-18 apartments) built in the 70-90s, the ASU consists of a single knife switch with 100 amp ceramic fuses. Additionally, a couple of years ago, RES was installed on the facade of the house with a direct connection control panel with 80 ampere automatic machines before and after the control panel (all this is on the line before the knife switch). The question is: taking into account the increased energy consumption in recent years, are these current parameters not enough? What maximum rating machine can I install on the line running from the driveway to the apartment, when reconstructing the electrical wiring in the apartment located in the above houses?
P.S.: I would be very grateful if you indicate how this is all calculated.

Admin, but do not tell me such a moment.
School. ASU is not ah there - tires, a number of PN amperes per 100 and a knife switch to de-energize these tires. The knife switch is again open, without any arc extinguishing, similar to the RC

The organization that formally serves everything at the school refuses to cooperate, so we will work ourselves. It is necessary to install a new socket for PN at 16A, and for this, de-energize the bus.

Question: in order to turn off the RC-x switch, it turns out that you must first turn off all the floor boards powered by these tires? Or reduce the current / wait until the current drops to some value (5-10 amperes per phase, or how much) and with a sharp movement of the handle to the center?

General Drozd, switch switch switch strife. Those that are equipped with arc chutes, they can theoretically cut off the rated load currents. Which cameras do not have, then only a very small current or no load at all. In practice, it is better not to take risks and do not turn off the load with knife switches. In your case, can't the load be removed in the floor boards by turning off the input or all outgoing machines in them ?!

In my case, colleague, there are no cameras there, the knife switches are not even covered by the front panel. There is not even a diagram of which floor boards are fed from here, from this section of the ASU. Therefore, it’s just that you have to extinguish half of the building by enumeration, one with a walkie-talkie on the floors, turns off the shields, the second looks at the currents in the phases of the section.
There is no protection there at all. Therefore, it seems that you will have to turn it off when the currents drop. Tell me, the comparison is childish, but if I turn off the working kettle from the outlet, then nothing sparks or burns there. This is 2500W. Is it possible to consider 10A as a conditionally safe shutdown current on an open switch RTs-2 or very similar?

General Drozd, as an option, if possible (for example, in the evening after training classes), then order the machine to be turned off at the TP from which your ASU is powered. Get the job done quickly. Small currents, of course, can be turned off, only carefully, it is better to wear gloves and a protective screen - this is just in case. Well, or act as you described. About the kettle - that's just the same and sparks, and over time, such sockets are replaced.

Helmet + Wolverine screen and latex gloves are mandatory, I always carry them with me and all the inclusions of unfamiliar devices are so.
Switching off at the substation at 19.00 and later not a single soul will go is not an emergency. And the school is studying until 19.10, so them.

If the electrical circuit breaks under load, there will definitely be an arc or sparking, but you will not do this all the time (as in the example with turning off the kettle). I am sure at 10-15 A there will be a dangerous destruction of the power electrical contacts of the knife switch, and even more so there will be no overlap between the phases.

Alexei:
06/20/2012 at 08:36
“It’s somehow not normal when the power cables block the meter terminal block”
I see no problem turning the outgoing cables from the current transformers to the common busbars by 45 degrees to the left. The plastic cable holders can be re-glued... access the wires from the calibration block to the meter.

They worked (another 8.04) at 12 amps on a larger phase. When turned off, it's very quiet, no sparks or crackling. Everything just went out.
Naturally, the handle work quickly.
When turned on, it sparked a lot more.
I attribute it to the fact that the school is full of GLL on lighting, both square dots for 4 and long ones for 2.

But these 12 amperes ... extinguished everything that they found. So still GDE_TO consumers sat. And this is a post-1992 entry school, not a devil-shed.

Looked completely a subject of this section and comments to it. As always done at a good technical level, in detail, arousing great interest among the audience of the site. Of course there are a few additions and comments (as without them). I would suggest making number marking of groups in the ASU. It is clear that the group numbers should be from left to right, but without this marking it is impossible to work.

Good afternoon.
I have a question: in our 5-storey building in 1965, everything was as you described for the old housing stock, but they raised money and did:
- in the ASU everything was changed to a new one (in the main ABB);
-changed to copper all the lines in the risers;
-new nuts resp. everywhere;
- made a ground loop for the house (TN-C to TN-CS);
-carried out the 5th PE ground wire; (3-phase, zero, PE)
- in the shields, new tires O and grounding were installed everywhere)

Is it necessary to change the cabinet in the ASU to a modern one with IP 31 or is there still no such mandatory norm?
The Criminal Code requires us to make a ground loop also for the premises of the ASU (in addition to the brownie) - is this mandatory or not?

Sincerely. Thanks for the site - it really helps a lot.

Dmitry, it is not necessary to change the ASU cabinet if it is in a satisfactory condition (not rusty), it has a lockable door, etc. During major overhauls, the ASU was changed only after an examination of its condition or when it was impossible to install new equipment in it.

Why make a separate memory circuit in the ASU room ?! This requirement is unfounded and redundant. If you have completed the separation of the PEN-conductor, then you will have the main PE bus (GZSH) installed in the cabinet itself, ground all metal structures on it if necessary.

Hello!

Is it possible to invite employees of your Electrotechnical Laboratory as experts to assess the state of the ASU in the MKD - Stalinka?

Thank you.
Sincerely,
Olga.

Good afternoon!
On your website, the input-distribution device (in the picture) shows the ASU -0.4kv of a residential apartment building, tell me its type and the complete set of the cabinet, I will be very grateful, from the calculation of the electricians they picked up the ASU -3-41-UHL4, but something I doubt the choice. I would also like to know, when choosing an ASP, it is necessary to take into account the number of apartments in the house (for example, in one 16, in another 100) or not, maybe the number of groups is different or the inserts are small. Are you needed, does the equipment change?
With respect to you, Head of the Production Department of PZhT LLC Vladislav Movchan.

Hello!
At our dacha, we have power from a two-wire SIP overhead line. Counter with machine 63A on a pole in front of the house. Switchboard with voltage relay, RCD, Diff. machine guns and circuit breakers home. The body of the meter box on the pole is connected to the PEN conductor and is not grounded. The house has a ground loop. I have three questions:
1) Is it necessary or not to ground the box on the pole (when the zero breaks to the meter and the consumers in the house are turned on, the box is energized)?
2) In this situation, where is the ASU - in the house or on the pole? After all, protect the meter with the introductory machine on the pole, and everything else in the house?
3) in such a situation, what system would be recommended and where to divide PEN into PE and N.
Thank you.
Sincerely.

Hello Tariel.

1. Yes, it will be energized, because. shield is not grounded, but zeroed. Read more about this in the article about.

2. The question is rather rhetorical, because according to the PUE, p. In fact, both shields belong to the ASU, they are simply separated from each other.

Good afternoon. Tell me please, for what purposes was the contactor used in the old ASU? Not for automatic lighting or what? I also met a board near the contactor with a trance, relays and other strapping (resistors, electrolytes). Of course, this has not been working for a long time. And I met a small box near the ASU box, also with a contactor, a scarf, light bulbs and toggle switches, and it was connected by cable to the ASU with more than 5 wires. But the cable was cut off and I could not understand which circuits the contactor closed.
You've probably seen this at work. What is it and why?

And yet, is it possible to replace fuse-links (100 A) with automatic machines? As I understand it, 100 A selective machines are used for these purposes?

Dmitry, remote control is possible, for example, street lighting or other automation. A step-down transformer should be installed there to power the basement lighting. Now it's hard to say...

You can replace fuses with automatic devices, but you need to make a calculation, taking into account the load, the selectivity of other protection devices, the cross-sections of the cores of outgoing lines, etc. In any case, there is no way to do without a project.

Good afternoon!
Home is 47 years old. Recently, in the ASP (input to the house, 380 V), the wires coming from one of the fuses began to heat up. The consequences are periodic flashing, power outages in some apartments and in the entrance. The fuses are glass 63 A. The emergency workers suggested replacing the fuses with ceramic 100 A. The question is whether this will help solve the problem if the wiring remains old. Will it not turn out that the fuses at the input to the house will let a strong current through, and somewhere in the apartments with the old value, something will suddenly light up?
Do fuses actually affect wire overheating? Outwardly, overheating looks like the tip of a burning cigarette, then it flares up and smolders, then it goes out, once several centimeters of wire became hot and the insulation was charred. After that, the emergency workers advised the fuses to be replaced.

I would not only change the fuses. Although it may not give anything. If one phase is heated (one of the fuses), this indicates that one of the phases is most likely heavily loaded. So it is necessary to "unload" it. It is necessary to measure the currents throughout the house.

Your emergency workers are strange, so raise the denomination.

The cause of overheating must be looked at, perhaps the point is not in the PNs themselves, but in the holders for them. Judging by what you described, you need to check all connections around overheating

Agree with General Drozd, all signs of a bad connection, but in any case, tell the electricians to check the currents in the phases, as Albert suggests.

Thank you. And an ordinary electrician from management company cope with phase measurements? Or is it the competence of the electrical laboratory? Documentation for the house is no longer found.

There is a suspicion that the contacts were oxidized just at the holder, and for some reason it is from this fuse that a wire of a smaller cross section comes from than others. He was raised (visible tape), and he is without a tip. But the stripped end of the wire goes to the bolt to the holder, but somewhere in the holder it sparks.

And another question arises. Does it make sense to replace the ASP at all without changing the rest of the wiring at home? Capital repairs are planned only in 2024. Do you need a project for a replacement? And from whom to order it?

It's strange, but what, there is nothing to measure and compare the currents in phases, even if it's not accurate, then it's impossible to compare? Is it difficult to go broke on the cheapest ticks? Rather, there is already an avalanche-like process - the first overheating due to poor contacts can lead to a deterioration in the connection and no matter what you put later, at least at 150A., and the contact, for sure, no one touched.

“Can an ordinary electrician from a management company cope with phase measurements? Or is it the competence of the electrical laboratory? I somehow cope, and there are also crusts on measurements and tests. It is necessary to change the fuse holder, and colleagues to the emergency workers are reprimanded, because they complicate their work (when the wire burns out, there will be much more fuss). In my memory, the PN fuse holder stopped conducting current at all, so the examinations were carried out on it (unofficially), they sorted it out on their own . We found out that the assembly contact, where the outgoing tip is attached, was burned inside.

I apologize in advance for the question. Unfortunately, we did not receive a response from our power engineers. So, the house is two-story, the ASU is installed in the entrance under the stairs. There is a lot of space there, and residents store bicycles, sleds, etc. there. It does not look very aesthetically pleasing. So I wanted to hang curtains, behind which everything will be hidden from view, including the ASU. But, I was warned that there could be problems with power engineers, threatening a fine for violating safety rules. Is this really so, and what documents regulate it? The ASU itself is not additionally fenced. Thank you.

Problems with power engineers can arise if the curtains in any way interfere with the maintenance of the ASU - complicate access, prevent the door from closing, get in the way. In general, first of all, you need to ask a question to residents who turn a potentially dangerous object into a pantry. Bicycles, sleds, what's next? Rags? fuel? I now thought that all the same against curtains. You will get a separate fenced room in which the tenants will start throwing all sorts of rubbish. It's not the point.

Problems will arise not only from curtains, but also from bicycles, etc., if something happens in the ASU or after it and you have to quickly get to it, and at that time sleds, buckets, basins fall on your head ...

So I'm trying to explain to people that shields and other things are not crap that needs to be removed to the far upper corner, but a workplace in an emergency. And then fill up access, lock it up with a refrigerator, a closet.

Vladimir.
I just wanted to know what documents regulate the operation of the ASU in terms of its location and access in terms of safety.

Regarding the discussion of this issue.
In my case, fears are absolutely vain. There is no mention of clutter at all. There are enough places. The ASU is located at the entrance to this space on the left, access is completely free. And the curtains are simply moved aside (they are on the rings), I don’t see any problems at all. The residents (there are few of them, the house is two-story) are well-mannered and friendly, the entrance is kept clean and tidy.

Zinaida, there are no prohibitions in the PUE about curtains, you can, as it were, visually separate the ASU from the stairs, it will be even better. On the curtains, I would hang a sign "Caution! Voltage". But it is advisable to remove sleds, bicycles, etc. from there, because. they can restrict access to the shield and in the event of an emergency, they can become a serious hindrance. In general, according to the mind, instead of curtains, it would be better to fence off this square, for example, with a metal grill and install a door with a lock.

Here are a few quotes from the PUE about the ASU: clause 7.1.28. VU, VRU, MSB, as a rule, should be installed in switchboard rooms accessible only to service personnel. In areas prone to flooding, they should be installed above the flood level. VU, ASU, MSB can be located in premises allocated in operated dry basements, provided that these premises are accessible to service personnel and are separated from other premises by partitions with a fire resistance limit of at least 0.75 hours. distribution points and group boards outside the switchboard rooms, they should be installed in places convenient and accessible for maintenance, in cabinets with a shell protection degree of at least IP31.

Thanks a lot!!! I will use your advice.

Hello, help me collect a lie, power comes 95 aluminum, the power of all consumers is 170 kW

Alexander, how do you imagine it? Here's what I can do. But where am I, where are you, who will take over your VRU, respectively, what requirements for the project, if any?

Or do you think that we can help you with words here, and you yourself? So it's not just one line.

Hi Everyone. I have a question about how the lighting of the shield itself should be powered. Before the counter or after? and on what basis normative documents it is connected to the knife switch .. Inspectors came from Energia OJSC and write me a fine for connecting the lighting lamp in the shield itself, I lie to the meter ...

really looking forward to the answer

I read it with interest. I have a question. In a couple of years, in my pre-revolutionary apartment building, a house is planned overhaul power supply. Do I understand correctly that the wiring should be replaced, including from the floor panel to the meter located in the apartment (only one machine per apartment is installed on the floor panel)? Will a PE entry be made up to the apartment panel?

Thank you for the detailed answer. Apparently, the amount of overhaul will depend on the amount of funding. Introductory machine for an apartment 16 A with a modern household appliances-it's nothing. So far there haven't been any real problems.

Hello! I purchased a non-residential premises of 17 sq. m in an apartment building in which an ASU is installed. Can I, as the owner, demand that it be moved?

Anton, the ASU does not apply to your property and any of its movements must be coordinated with the management company or networks serving your home. Even if you are given permission to move it (although it is unlikely), then you still cannot do without a project.

Hello) do not prompt? Is it possible to connect 2 consumers to one group of inserts in a switch cabinet (assembly) 0.4kV. And vice versa, connect one consumer to 2 groups of inserts (because the tweezers in the first group in phase "C", for example, broke, and on hastily connected to another group), is this allowed by the rules or not?)) All consumers are 3-phase, if you tell me the point in the PUE where this is written, I would be very grateful)

Hello, please tell me what kind of knife switch is installed in the photo under the following description "In this VRU-0.4 (kV), the power lines are protected by similar glass fuses, and the lighting circuits are protected by ceramic cork fuses (plugs) of the PRS type."
Replacement is required, I can not find the marking in order to order (complete with a cell, when disconnected, the fuses move forward from the fixed knives).
Thanks in advance.

Konstantin, this is also an ordinary knife switch with fuses with a side drive (for example, RPS-4 type), the handle of which is located on the surface of the panel or shield case.

Find analogues without problems, they have the same designation.

There are options for circuit breakers with fuses, but only placed in separate boxes. Their designations are YABPVU.

Hello. My private house will be connected to the network, I need to make an ASU, which I plan to hang outside the house. Inside there will be an SPD, a meter, a division of PEN into PE and N. Rosseti gives me 15 kW. 0.4 kV. I decide which introductory machine to put in, so that in the future, if a short circuit happens in the house, I would not turn off the introductory in the ASU and do not have to run outside to turn it on.
Actually, is it permissible to put a D25A introductory machine in the ASU, if there is an introductory C25A machine further down the line in the house in the ShchR?

Alexey, it all depends on the magnitude of the short-circuit currents, under certain conditions both can work. I wouldn't do that in your case. At the input in the house, I would not install C25, but a HV load switch. So selectivity will be observed between the introductory and outgoing machines, and the switching device will remain, with which you can turn off the whole house at once.

Dmitry, VN is convenient, but it turns out that the meter and the line after it remain without short circuit protection.

Alex, you are wrong! The introductory machine protects the line from its lower contacts and to the nearest outgoing machine in the house.

I mean, if in this scheme we replace the introductory machine with a VN.

Aleksey, you first asked about two automatic machines, one in the ASU on the street, and the other in the house. I told you that it is not necessary to install an automatic machine in the house, and if you really want to, then instead of the automatic machine, you can install a load switch. Please note that I did not give you recommendations to replace the machine on the street, and the sales company will not go for it, because. the allocated power is just the same and is determined by the nominal value of this machine.

Good day! I want to apologize in advance for the stupid question. But it worries me, I can’t do anything. Tell me, please. In the new building, the ASU is installed on the first floor, there is a separate entrance from the street. Installed on our riser, our apartment is on the third floor. Is there any harm from such a neighborhood? The kitchen is located in this area. And on the second one too ordinary apartment. Is this allowed by the rules?

Yana, the norms allow and harm such a neighborhood in itself does not carry!

What is the harm and why?

Thank you very much for your reply!

Good afternoon, Dmitry.
Currently, the Criminal Code is placing the ASU on the facade of a private house. How does this agree with the requirement of the PUE clause 7.1.30 (The room temperature should not be lower than + 5 ° C.). And what is this requirement about + 5 C based on?

Hello. Here is a question. There is a building-kindergarten, in it the ASU, which is sometimes heated. Many fasteners in it and in the main switchboard are rusted and in poor condition. On the basis of what regulatory documents can they issue an order to bring the ASU into the proper form?

Michael, this is a broad question. Surely, in addition to rust, there is a lot to pay attention to. On your question, here is an excerpt from one court ruling on a similar problem: there are traces of flooding of the premises, the pipeline is covered with rust, there are traces of corrosion of metal parts of electrical panels and electrical equipment (EIC clause 7.1.28, 1.1.20 PTEEP clause 1.7.2).

Hello! In the photo I'm lying, taking into account, the fuse holders are installed on a solid sheet .. is this permissible? Is it not necessary to put them on special rails?

Hello dear.
Thank you all for the interesting questions and answers. In the internet, for some reason, there is no normal information about single-phase STPs. Although, this is very a good option power supply of a private house or cottage.
On a concrete support of a 10 kV overhead line, a STP 10 / 0.23 kV was mounted, a small single-phase transformer was installed. A 220V cable descends from it along the pole. Below,
on the same support, a shield with automatic machines and a 220V meter is installed.
Can this shield be considered RUNN or RU? Is this correct or not? The electrician did not accept from the networks, he said it was impossible to install a metering board on a 10kV pole.
Do you need another shield and another counter on the wall of the house? Wooden house.

Good afternoon. I would like to ask a question, in the work a small lie for the object.
According to the project, two supply lines go first to 160A atoms, then through the meters to the changeover switch.
This scheme is not familiar to me, I assumed that the introductory lines should first go to the changeover switch, in my case it is ABB OT400. Something tells me that the project is illogical ... am I right?
Thank you.

VU (input device), ASU (input switchgear), MSB (main switchboard), RP (distribution point).

VU (input device) - a set of structures, devices and devices installed at the input of the supply line to the building or its separate part.

ASU (input-distribution device) is an input device with devices and devices for outgoing lines.

MSB (main switchboard) - a shield through which electricity is supplied to the entire building or its separate part.

RP (distribution point) - a device in which protection devices and switching devices are installed for individual electrical receivers or their groups.

Group shield - a device in which protection devices and switching devices are installed for individual groups of lamps, socket outlets and stationary electrical receivers.

Floor switchboard - a switchboard installed on the floors of residential buildings and designed to power apartments or apartment switchboards.

At the entrance to the building, a VU or ASU should be installed. One or more VU or ASU can be installed in the building.
If there are several economically isolated consumers in the building, it is recommended to install an independent VU or ASU for each of them.
From the ASU, it is also allowed to supply consumers located in other buildings, provided that these consumers are functionally connected.
With branches from overhead lines with a rated current of up to 25 A, the VU or ASU at the inputs to the building may not be installed if the distance from the branch to the group shield, which in this case performs the functions of the VU, is not more than 3 m. This section of the network must be carried out by a flexible copper cable with conductors with a cross section of at least 4 mm2, flame retardant, laid in steel pipe, while the requirements for ensuring a reliable contact connection with the branch wires must be met.
For air inlet, surge suppressors must be installed.
It is not allowed to install additional cable boxes before entering buildings to separate the service area of ​​external supply networks and networks inside the building. Such separation should be carried out in the ASU or MSB.
VU, VRU, MSB must have protection devices at all inputs of supply lines and at all outgoing lines.
At the input of the supply lines to the VU, ASU, MSB, control devices must be installed. On outgoing lines, control devices can be installed either on each line, or be common to several lines.
The circuit breaker should be considered as a protection and control device.
Control devices, regardless of their presence at the beginning of the supply line, must be installed at the inputs of supply lines in retail premises, utilities, administrative premises, etc., as well as in the premises of consumers, separated in administrative and economic terms.
The floor shield must be installed at a distance of no more than 3 m along the length of the electrical wiring from the supply riser.
VU, VRU, MSB, as a rule, should be installed in switchboard rooms accessible only to service personnel. In areas prone to flooding, they should be installed above the flood level.
VU, ASU, MSB can be located in premises allocated in operated dry basements, provided that these premises are accessible to service personnel and are separated from other premises by partitions with a fire resistance limit of at least 0.75 hours.
When placing VU, ASU, MSB, distribution points and group shields outside the switchboard rooms, they should be installed in places convenient and accessible for maintenance, in cabinets with a shell protection degree of at least IP31.
The distance from pipelines (water supply, heating, sewerage, internal drains), gas pipelines and gas meters to the installation site must be at least 1 m.
Switchboard rooms, as well as VU, ASU, MSB, are not allowed to be located under sanitary facilities, bathrooms, showers, kitchens (except for apartment kitchens), sinks, washing and steam rooms of baths and other rooms associated with wet technological processes, except for cases when special measures are taken for reliable waterproofing, preventing moisture from entering the premises where switchgears are installed.
It is not recommended to lay pipelines (water supply, heating) through electrical switchboard rooms.
Pipelines (water supply, heating), ventilation and other ducts laid through switchboard rooms should not have branches within the room (with the exception of a branch to the heater of the switchboard room itself), as well as hatches, valves, flanges, valves, etc.
Laying gas and pipelines with flammable liquids, sewers and internal drains through these premises is not allowed.
Electrical room doors must open outwards.
Premises in which ASU, MSB are installed must have natural ventilation and electric lighting. The room temperature should not be lower than +5°C.
Electrical circuits within the VU, ASU, MSB, distribution points, group shields should be carried out with wires with copper conductors.

Hello. Introductory device ASU (in the particular case of VU) is a necessary element of the electrical circuit. Multi-storey building, office building, production room, a private house or a cottage, it doesn’t matter, everywhere, during construction or major repairs, you can come across a metal cabinet called - input switchgear ASU.

What is ASU, appointment

- this is an electrical switchgear in the form of a cabinet with a lock, with devices and devices installed in it. Such as: electricity meters, circuit breakers, knife switches, fuses, ammeters, voltmeters, etc.

The ASU device is used to receive, distribute and account for electrical energy at industrial, residential and administrative facilities. To protect the line and electrical equipment from overloads and short circuits in the network, as well as to implement operational switching on and off of equipment.

Introductory switchgear, installation

They are installed in special rooms, according to the power supply project, at the input of the power cable and supplies the entire building with electricity. In residential buildings this is most often a basement, the splitting of the combined neutral conductor is also done there, it’s more convenient. Served.

ASU cabinet should be located at a distance of at least 1 meter from other communications. In an accessible, well-lit, ventilated area to ensure normal operation and maintenance.

Input and output of power cables is usually done from below, but when ordering installation services and , you can make changes to . If the ASU is to be powered from an overhead power line, then surge arresters should be installed. The doors of the premises where the input-distribution device is installed must open outwards.

If the building, house or other structure is large, it is recommended to install a separate ASU for each input. After them, additional switchgears can also be installed - switchgear, with necessary equipment for the operation of electrical receivers of individual apartments and premises. I present to you the video:

ASU device of a multi-storey building

Let's analyze some elements of input-distribution devices:

W wires (conductive, grounding N, grounding PE), copper or aluminum. The wires are attached to the busbars using bolts with washers. To ensure a reliable connection, you must use .

BUT automatic switches, fuses. The rated current of the circuit breakers is selected according to the electrical project, or calculated from the power. Intended for wiring protection from overload, short circuits, overcurrents, etc.

With electricity meters. The name itself says why they are needed.

O voltage limiters, arresters. Protection against impulse overloads.

AT oltmeters and ammeters. For visual control of load current and voltage.

P wires and cables, for switching electrical appliances of the circuit. All wires must be insulated, multi-colored, according to GOST:

• N neutral - blue or light blue
• P E earth - yellow-green
• L phase can be black

Don't neglect it! The marking and color of wire cores must be observed throughout the chain, remember this!

ASU marking

Blog news

News #1. 333 comments, . This time it was left by the most active commentator of the blog Sergey Panagushin. The gift is 100 rubles for a mobile phone. Thanks for the additions Sergey, your comments are the best!

It seems that everything, the input switchgear of the ASU was dismantled, if there are additions, leave comments. Coming soon - ASU for a cottage or a private house, subscribe to the news if you are interested.