Connection of a single-phase electric meter and automatic machines: standard schemes and connection rules

Amir Gumarov
Checked by a specialist: Amir Gumarov
Author: Mikhail Yashin
Last update: May 2019

To calculate the consumed electricity and protect the network at most residential and residential facilities, it is necessary to connect a single-phase meter and automatic machines. This event is usually to be performed by the owner of the premises.

If you have small skills in working with wiring, you can independently do this work without involving third-party specialists, and we will tell you how to do it.

Typical single-phase network input circuit

The vast majority of apartments, gardens and small household objects such as garages have a single-phase network. The method of connecting the measuring device (electric meter) and circuit-protecting elements (RCDs, circuit breakers and differential machines) is the same.

Depending on the operating conditions and powered devices, the connection diagram of a single-phase electric meter can undergo the following changes:

  • Lack of input "land".
  • The lack of an individual introductory machine in front of the counter. It can be common to several circuits equipped with metering devices, or an ordinary manual switch (circuit breaker) can be installed instead.
  • Lack of branching into several chains.
  • Lack of RCDs and automatic machines protecting the line after the counter.

If there are no automatic machines or RCDs between the meter and consumers, then in the event of a short circuit or significant overload, the metering device will break. Therefore, protection immediately after the meter is needed, especially since the simplest circuit breakers are cheap.

Typical Single Phase Power Input
A typical scheme for introducing single-phase power to an object. It is in this sequence that all the elements must be connected so that the system functions normally

Separation of liability for electrical appliances

The electrical wiring of the facility is protected by separate switches that regulate the maximum allowable current for sections of the circuit.Payment for their acquisition and connection is made by the owner of the premises.

The electric meter and opening machine can be physically located not only in the consumer's area of ​​responsibility. If these devices are located in a privatized apartment, in a garage, in a domestic building or within the boundaries of a cottage or a summer cottage, then their installation, maintenance and replacement are carried out by the owner of the property.

Electrical panel on the external wall of the house
According to modern requirements, a shield with an electric meter should be installed outside the cottage or cottage. Therefore, now they produce models that work at low temperatures

His duties also include providing access to the energy services and management company to the meter for taking readings, sealing it or checking it. Also, experts have the right to install magnetic seals. If the premises user refuses admission to the territory without good reason, the electricity supplier can transfer it to the general tariff.

If the devices are located in the municipal (non-privatized) property, in the common house territory (entrances) or outside the private area, then all expenses are borne either by the supplying organization, or they are shared. In this case, the organization of work and payment is made by the management company, HOA, GSK or a horticultural partnership.

In more detail about the legal intricacies of the replacement and installation of electricity metering devices we described in this stuff.

Connection of the counter and automatic machines

If the place for installation of metering and protection devices is located in the area of ​​responsibility of the owner of the premises, then it is necessary to install them according to the standard scheme for connecting the electricity meter and automatic machines.

Switchboard Installation

For ease of installation and protection of electrical appliances, it is best to use switchboards specially made for this purpose.

Electrical panel in the apartment
According to clause 7.1.7 of the PUE, such complete devices are referred to as apartment shields. Their cost starts from 250 rubles and reaches 10 thousand

Usually, only equipment of the following type is installed in such a shield:

  • introductory machine;
  • electricity meter;
  • circuit breakersfuses and other control and protection devices;
  • residual current devices;
  • terminals, buses and other switching elements;
  • elements of non-power networks, for example, for cable television;
  • uninterruptible power supplies direct current with external batteries;
  • control units of the smart home system.

A metal or plastic box protects the devices placed in it from physical impact, moisture and dust. Apartment panels located in the consumer’s area of ​​responsibility will not be sealed so that the owner of the premises has access to circuit breakers. This procedure is carried out only for the counter.

The panels are equipped with a special profile, which is made of plastic or galvanized metal - a DIN rail. All modular equipment, including counters, is mounted on them. This allows you to compactly and reliably place block equipment.

Switchboards come in two types:

  • Mounted. Their back wall is collapsible. It is removed and attached to the wall using self-tapping screws with dowels, and then put on the body. When choosing this option, you need to determine in advance the place of the plant in the wiring board.
  • Flush mounting. In this case, a niche must be hollowed out under the flap.

When choosing a model, you must first make sure that there is enough space for all components of the electrical system control. It is better to take a shield with a certain supply of volume, since in the future it is possible to connect new automation.

Flush-mounted electronic switchboard
The flush mounted shield will not protrude from the wall. But the amount of work needed to install it is much more than for mounted models

If you need to install a switchboard on the street, then for this there are special models that will protect the equipment from rain, snow, strong winds with dust and other natural phenomena.

We also recommend that you read our other article, where we examined in detail how to connect an electrical panel. More details - go to the link.

The need for an introductory machine

The need to install an introductory machine and its face value can be specified in the contract for the provision of services for the supply of electricity. If there are no such requirements, then the machine is still better to use.

The fact is that for installation and work with meters and control the supply of electricity, it is necessary to disconnect the network. If the introductory machine is located on the territory of the consumer, then you can independently turn it off.

Otherwise, it is possible to turn off the electricity supply only with the permission of the electricity supplier, and it will be necessary to call a specialist, since access to the general distribution panels of outsiders is prohibited.

This creates the following problems:

  • it is necessary to agree on the time of shutdown;
  • if several consumers are connected to one switch, you will have to notify them of a temporary power outage;
  • calling a specialist in an emergency will cost money.

Time for all work when the power is off will be limited. Therefore, you need to immediately prepare a place, a tool and perform preliminary steps that do not require a lack of power.

Bipolar input circuit breaker
Introductory machines with a nominal value of 32-64 A are inexpensive: from 300 rubles for the Chinese EKF to 1000 rubles for the French Legrand or Schneider

Therefore, before connecting automatic equipment and a single-phase electricity meter, it is better to install an input automatic device once than if you need to work with your electricians every time you need to work in your own electrical panel.

Modern electricity meters

Now there are two types of meters on electrified facilities: obsolete electromechanical or new electronic. There are two main indicators for any type of electric meter.

Accuracy class (CT) determines the maximum permissible error in percent when measuring electricity. Currently, there are classes of household meters (from the lowest to the highest): “2.5”, “2.0”, “1.0”, “0.5” and “0.2”. According to paragraph 138 of Decree of the Government of the Russian Federation No. 442 dated 05/04/2012 for individuals, this parameter must be 2.0 or higher.

Therefore, when buying a device there is no need to purchase models with a higher class, for example, “0.5”. They are less running and more expensive, so managers of trading companies often try to sell such devices to customers unfamiliar with the topic.

The second important indicator is the maximum current that the device can pass through itself. For domestic and residential premises, this indicator for a single-phase device cannot be more than 60 A.

Household single-rate single-phase electric meter
A domestic one-rate meter of the Russian manufacture of accuracy class “1.0” and designed for operation with currents up to 60 A costs about 600 rubles

There are also multi-tariff meters that can be programmed to calculate the consumed electricity in different daily periods.

Most metering devices are mounted on a DIN rail in a distribution panel. At the same time, the model of the shield and counter must be selected in such a way that it was possible to take readings through the window without opening the door - this is very convenient.

The single-phase meter has 4 power terminals for connecting wires. Always, if you look at the device, then they go from left to right in the following order:

  1. The coming phase.
  2. Outgoing phase.
  3. Coming neutral.
  4. Outgoing neutral.

Before starting installation work, it is necessary to disconnect the wires: disconnect the incoming machine or switch, and also be sure to check the absence of voltage multimeter or indicator screwdriver.And not only in phase, but also in neutral.

Both the counter and all automation are mounted on a DIN rail using the latches they have.

Assembly of the electric meter on the table
All the work on completing the shield is more convenient to perform on the table. Therefore, it is better to first completely assemble the structure, and then attach it to the wall

Next, you need to strip the wires that go from the input machine, using insulation puller or clerical knife. The length of the segments should be such that they do not hang out, but also are not tight. The cleaned ends are inserted into the clamps and tightened with a screwdriver, and both screws must be properly stretched.

Circuit Breakers and RCDs

With your own hands, you can connect not only an electricity meter, but also automatic machines that will protect the line and metering device from overload and short circuit.

All devices are also mounted on a DIN rail. Automata connect only to the phase, and RCD - also to the neutral, which is displayed on the bus. It is advisable to leave a small space between the machines, since they are heated during operation, and the access of air from the sides helps cooling.

The ground wire goes separately to its bus. He does not go into the counter, as well as in machines and RCDs.

Conclusions and useful video on the topic

Completing the shield with a counter, automatic devices, a socket and tires:

DIY apartment panel assembly:

It is quite simple to replace or install a single-phase meter independently. But when working with electricity, safety rules must be observed. Including do not change the sequence of devices in the connection diagram.

If you possess the necessary knowledge and skills to connect a single-phase electric meter, please share it with other visitors to our site. Tell us about the nuances of connection that are known to you. Leave your comments, ask questions in the block under the article.

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Visitors Comments
  1. Anton

    What happens if you mix the phase with zero on the counter? He will not burn, how will he count?

    I also heard that you can not put the machine in the zero wire in front of the counter and after it, so as not to violate its integrity. Installing additional machines on the neutral wire will lead to additional leaks, and when you turn on powerful electrical appliances, it will wait for voltage.

    I would be grateful for the clarification.

    • Expert
      Amir Gumarov

      Good afternoon, Anton.

      For clarification, I attached the circuit of the induction meter. Briefly, how does it work:

      - coils 4 and 3 create magnetic fields of a certain direction;
      - the resulting magnetic field crosses the disk;
      - the currents induced by the field interact with it, causing the rotation of the disk.

      If you confuse the phase with zero, then the directions of the fields will change, the direction of the current in the disk - the counter will begin to rewind the readings. True, the designers have provided for the possibility of error in the latest models, providing electric meters with a backstop. As you see, nothing will burn.

      With an electronic meter, the situation is different. I took at random a single-phase, single-rate passport CE101-R5. The instructions say that there is an indicator informing of “reverse power” (attached screenshot).In other words, the counter, if the phase is mixed up and zero will warn that a mistake has been made. It turns out that also does not burn. If other types of meters are interesting, I advise you to look at the passports.

      How to mount a counter, machines - it is written in the article. Do not use rumors.

      Attached photos: