All existing models of electricity meters are designed to perform one main function - they measure the amount of electricity consumed by the consumer. As a rule, specially trained people are hired to install electricity meters. But if you really want to, you can install such a device yourself. You just need to thoroughly understand the connection diagram and follow the instructions in everything.
Remember: only you are responsible for all possible consequences of unauthorized installation of accounting equipment.
| Parameter | Classification of electricity meters |
|---|---|
| Type of current used | constant and variable |
| Number of phases | single-phase, three-phase |
| Number of tariffs | single and multi-tariff |
| working mechanism type | mechanical, electronic and hybrid electricity meters - a rarely used intermediate option with a digital interface, an inductive or electronic type measuring part, a mechanical computing device |
| By connection type | devices for direct connection to the power circuit and devices for transformer connection, connected to the power circuit through special instrument transformers |
There are two main types of meters on the market: induction and electronic. They differ in their mechanism of action and measurement accuracy.
Induction models are rapidly being forced out of the market. The government is actively promoting this. The main disadvantage of devices in this category is that they are very easy to “deceive,” which unscrupulous consumers happily take advantage of.
Electronic meters are more versatile, compact and accurate. An additional advantage of modern models is the ability to configure them to work in . This point is especially relevant for consumers living in regions with different tariffs for daytime and nighttime.
Thus, when choosing for self-installation, it is strongly recommended to give preference to modern electronic models.
Additionally, meters are classified according to indicators such as accuracy class and rated current. The smaller the meter class number, the more accurately it works.
The required rated current is determined individually. To calculate, check with your local energy sales office for the permissible active power indicator established per consumer. This number must be divided by 220V or 380V depending on the voltage of your electrical network.
For users connected to a three-phase network, a higher active power threshold is usually set, however, using a three-phase connection in everyday life is not entirely advisable.
Important! If the meter is connected to buildings for which the calculated current value exceeds 100 A, current transformers are additionally installed. Directly “embedding” the measuring device in such conditions will not work.
In such situations, it is important to take into account that the inclusion of intermediate elements in the circuit can negatively affect the accuracy of accounting, so planning a transformer circuit must be approached with knowledge. To do this, it is better to contact a qualified specialist.
When choosing a meter, be sure to pay attention to the integrity of the seal and how long ago it was installed. You will find the seal on the screws of the meter casing. The maximum permissible limitation period for installing a seal for single-phase devices is 12 months, for three-phase devices - 24 months.
Self-connection of the meter: what does the law say about this?
To avoid problems with the energy sales service, first contact its local representative to conclude an agreement and obtain the necessary permits to carry out the planned work.
An employee of the mentioned service will give you documents that, among other things, will detail the requirements that must be observed before and during the installation of the electric meter.
The law requires that meters connected to private houses be installed outside the residential premises. This is done so that, if necessary, an energy sales service employee can gain access to metering equipment. The law obliges apartment owners to install metering devices in a common panel, located, as a rule, on the landing.
Studying the meter connection diagram
We will not consider complex connection options - we will leave them to professionals, because... Without the appropriate skills, it is unlikely that you will be able to cope with such work on your own.
The simplest option is . It is performed using a maximum of 6 cables and load. The ground, phase and neutral wires are connected to the input of the meter. Similar wires are connected to its output.
An automatic switch is installed in front of the meter. This is done for greater safety and ease of use. A small device will independently disconnect a house or apartment from the power supply if any kind of dangerous situation occurs.
To avoid problems with the energy sales service, be sure to seal the switch. To do this, we use a basic kit consisting of a mounting DIN rail, a seal and a plastic box.
The design of a typical electric meter includes a bus. This product is made in the form of a copper strip. Dielectric clamps are used to secure it. A number of holes are made along the length of the bus for supplying electrical cables and their subsequent fastening. This connection method is relevant when it is necessary to combine several separate wires into one cable.
Meter installation: basic rules and requirements
We install the electric meter in strict compliance with the approved rules. First of all, we study the safety requirements for the operation of electrical equipment of any type and purpose.
- We install the meter at a temperature not lower than +5 degrees. Accounting equipment, like any other electronics, does not withstand exposure to cold.
- When installing the meter outdoors, we build a sealed heated cabinet for it. All materials and equipment necessary for this are sold in specialized stores.
- We mount the electricity meter at a height of 1-1.7 m above the base. If the device is placed lower, it will simply be inconvenient for you to watch the readings.
Step-by-step instructions for installing the meter
First of all, we prepare the kit for work. We will need the following:
- counter and shield;
- installation tools with pre-insulated handles;
- insulators;
- switches (automatic);
- wires;
- fasteners (screws and nuts);
- voltage meter;
- DIN rails.
First step
Let's find out whether our electrical network is single- or three-phase. We calculate the required number of switches.
Second step
We install the metering device into the body of the protective shield. Fastening is carried out using special clamps from the kit.
Phase A enters meter terminal 1 and exits terminal 2 to the load; phase B enters terminal 3, exits into 4 and phase C enters 5, and exits from 6. 7 and 8 are zero
Third step
We install switches. We will attach them to the DIN rail with a special spring-loaded latch. We first fix the rail itself with screws to the support insulators.
Fourth step
We install grounding and protective busbars. We attach them to a DIN rail or insulators in the body of the protective shield. Fixation is carried out with screws and nuts. We place the buses at such a distance that the possibility of shorting the wires is excluded.
First, we connect the load to the switches, then we connect it to the meter, and only after that we connect the meter itself.
Fifth step
We connect the loads. We connect the phase to the lower terminals of the switches, connect the zero to the zero bus, and connect the ground wire to the ground bus.
Sixth step
We install jumpers connecting the clamps on top of our machines. Jumpers are sold in specialized stores. We first buy the required number of jumpers according to the number of machines.
Seventh step
We connect the electric meter to the load. To do this, we connect the “phase” output (which is the third terminal of the metering device) to the upper terminals of the machines. Next, we connect the “zero” output (represented by the fourth terminal of the metering device) to the zero bus.
Eighth step
We fix the body of the electric meter panel on a wall or other suitable flat base. Maintain a comfortable height.
Ninth step
We find phase, zero and grounding. If there is no grounding, we check each core with a special indicator. This simple device will help us find the phase. If there is a ground connection, you will easily recognize it - usually this wire is painted or marked green.
Tenth step
We turn off the electricity supply to the house or apartment.
Eleventh step
We connect the zero wire to the third terminal of the meter, and connect the phase cable to the first terminal.
Twelfth step
We check the operation of the electric meter at idle, and then gradually apply the load.
Thirteenth step
We contact the local energy sales office for additional checks and sealing of metering equipment.
At this point, the work of manually installing and connecting the electric meter is completed.
Congratulations, you have successfully completed all the activities and saved money on the services of third-party installers!
Find out how to do this, and also consider how to plan and calculate an electrical network from our article.
Video - Electric meter connection diagram
In the last few years, private country houses and garages have increasingly become connected to three-phase power supply networks. This is due to an increase in the number of consumer electrical appliances and their power. Such a connection has two main advantages: higher quality of power supply and balance of the three-phase system - the ability to simultaneously connect several powerful electrical receivers to the network, avoiding the occurrence of phase imbalance.
The essence of this phenomenon is as follows: one or two phase wires are overloaded, and the third is underloaded or not used at all. The uneven distribution of electrical energy in the network leads to the fact that when summing the load resistances in the circuit, an equalizing current and bias voltage arise, which can lead to serious malfunctions of the connected equipment, including its failure. Phase imbalance leads to an increase in energy costs, rapid wear of devices, a reduction in the service life and a decrease in the quality of their work.
RA,RB,RC – active resistance of loads by phase,RA>RB>RC≠0;UA,UB.UC – phase voltages,OUA,O.A.B,OUC – linear voltages.
The use of voltage stabilizers and baluns in three-phase networks allows the power source to generate an EMF of the correct sinusoidal shape with constant power throughout its entire period.
There are three types of three-phase electricity meters:
- Direct inclusion;
- Semi-indirect inclusion;
- Indirect inclusion.
Direct connection meters
This type of metering devices has a current limit of 100 A and is used with a small number and low power of consumers (up to 60 kW) and is connected to the network directly through a terminal block with eight contacts installed in the meter according to the following diagram:
L A ;L B ;L C – phase conductors.N – zero working conductor.
When performing installation work, it is extremely important to observe the phasing of the wires - incorrect connections cause additional errors in the device. The alternation of voltage phases is carried out clockwise: ABC – BCA – CAB, the correct sequence of connecting the wires can be determined using a phase meter or a VAF device.
Semi-indirect counters
In electrical networks designed to supply power to powerful consumers, such as heat guns, welding equipment, machine tools, etc., metering devices are connected using isolating current transformers. This need is due to the fact that the total load of electrical receivers exceeds the rated current of the meter. Transformers are installed in the gap of the supply wires.
Semi-indirect meters can be installed according to the following common schemes:
- Star connection of current transformers;
- Connection via test block.
The ten-wire circuit provides separate current and voltage circuits, which makes it safe to use and maintain, but it requires a large number of wires.
Contact terminals:
- Phase wires (A; B; C): 1, 4, 7 – input, 3, 6, 9 – output;
- Measuring phase windings (A; B; C): 2, 5, 8 – input;
- Input neutral wire: 10;
- Neutral wire: 11.
Transformer contacts: L 1 – power line input, I 1 – measuring winding input, L 2 – power line output, AND 2 – measuring winding output.
PE – grounding conductor, connected to the zero bus.
When connected in a star, all outputs of the measuring windings of transformers I 2 converge into one current node and are connected to the 11th terminal of the meter. The output terminals of phase wires 3,6, 9 and the input terminals 10 of the neutral wire are interconnected and connected to the neutral bus.
According to the PUE, clause 1.2.23, metering device circuits must be routed to independent assemblies or separate sections in a common row of terminals. In their absence, a test block (block) must be used, which allows short-circuiting the secondary windings of the current transformers, de-energizing all current circuits of the device during its maintenance or replacement, and connecting a reference meter with the load on. The device connection diagram is ten-wire; the test unit is installed between the meter and the transformers.
There is also an outdated seven-wire meter connection scheme; in this case, its primary and secondary circuits are galvanically connected by copper jumpers, which poses a threat of electric shock to personnel when servicing the equipment, so the use of this method is extremely undesirable.
Indirect switching meters are used in industrial environments and are not found in households.
How to choose a three-phase meter?
First, you need to make sure that the connection of the device is provided for by the type of power supply network - three-phase meters can be used in four-wire networks 220/380 V or 230/400 V. Next, you should set the operating current of the meter based on the size of the load taken into account by the device, which corresponds to the rated current of the input circuit breaker premises.
Significant energy savings can be achieved by using multi-tariff meters that have a “day-night” position and calculate electricity consumption at night at reduced tariffs. A significant advantage will be the presence of an internal tarifficator and power profile in the device, which makes it possible to manage tariff transitions, record the load schedule and keep track of the power consumption values of electrical receivers at any time period. Also, when choosing a metering device, its accuracy class (from 0.2 to 2.5) and temperature range (from – 20º C to 50º C) are of great importance.
Installation work for installing a three-phase meter
There are two ways to mount a meter in a switchboard:
- With three screws (for housing types S or Ш);
- On DIN rail (R. or P housings).
In the second installation option, the position of the DIM rail is adjusted so that all mounting holes in the device platform and in the shield coincide.
An electricity meter is needed primarily by the energy supply company, and the consumer is obliged to install it in an apartment, house, garage or country house. Mostly single-phase appliances are installed in apartments. A three-phase meter is usually connected in private homes.
Many meters have been installed for a long time and require replacement. The main reasons for this are:
- end of service life;
- loss of measurement accuracy (below second class);
- the need to install a multi-tariff device.
Installation of a new meter can be done with the help of professionals or independently. There are no particular difficulties here, but the rules must be followed.
Which counter should I choose?
Previously, mechanical type meters (induction) were manufactured. Their production continues to this day, installation is permitted by energy supply companies. Old designs are already being replaced by electronic digital devices. Both options do the same job, but mechanical ones are less resistant to low temperatures. It is important that the device passes through which should not be lower than the second one.
How to connect a three-phase meter?
The connection is made from the appropriate power supply.
It is required in a house equipped with an electric boiler, machine tools, electric stove and other powerful equipment. A distribution cabinet with protective devices for one and three phases is installed at the entrance. The input from the external network consists of 4 or 5 wires, where 3 current-carrying, neutral and ground wires are used. Grounding can be installed separately.
The three-phase meter is connected to the network directly or through step-down voltage and current transformers. They are installed in the power part of the circuit when the circuit power is higher than that of the device. A direct connection is made to three current-carrying wires of the network L1, L2, L3 and N (Fig. below). The phase and zero outputs on the terminal block are shown as L1", L2", L3" and N". Each output terminal is located next to the input terminal.
Nowadays many models are produced, the number of terminals and circuits of which may differ. For example, the connection of a three-phase meter "Mercury 233" from the input side is made to terminals 1, 4, 7, 10. Therefore, it is necessary to pay attention to the diagram indicated in the device passport. The connection of the three-phase meter "Energomer" is done according to the usual scheme described above.
Important! The power consumption is indicated in the passport for the meter. If it is exceeded, this may cause failure of the device and even fire. To select a suitable meter, you must first calculate the total power of consumer devices. It is taken with a reserve if the load is expected to increase in the future.
Features of connecting a three-phase meter
The features of the procedure are:
- You must first purchase all components for installation: distribution board, electric meter, automatic devices, RCD.
- To safely service the meter, a three-phase machine must be installed in front of it.
- The external power cable is first connected to the input circuit breaker.
- From the machine, three phases are connected to the meter, and after it, through an RCD, to the load.
- When connecting the cable, do not confuse the phase and neutral conductors.
- Grounding to the device is connected to the RCD.
Rules for connecting an electric meter
Since the metering device is primarily needed by the energy supply company, all actions related to the connection are carried out with the participation of its representatives. You can do the installation yourself, but at the last stage you need to call an inspector. When working, you must remember the following:
- Installation is associated with strict rules and regulations that the management company requires compliance with.
- Seals from the manufacturer and the energy supply company are required so that the consumer cannot change the connection diagram. After sealing, you need to receive an acceptance certificate.
If the meter is installed without the participation of the energy supply organization, it will not be considered a monitoring device. This will be an ordinary electrical device, like an RCD or an automatic device.
Connecting a three-phase meter "Mercury 230"
The frequently installed Mercury meter is characterized by many different functions. It measures reactive energy in both directions. Various modifications allow you to calculate energy according to one or several tariffs, as well as remember information over a long period of operation. Main characteristics of the meter:
- the ability to select a device by maximum and rated current, as well as by accuracy class;
- accounting for bidirectional energy consumption;
- availability of event logs and indicators;
- the interval between verifications is 10 years;
- service life - up to 30 years;
- availability of interfaces and modem.
Connection diagrams
The connection of the three-phase meter "Mercury 230", as well as all others, can be done directly to the network wires or through if there is not enough power. There are 8 terminals for connecting the cores. Terminals 1, 3, 5 are used to connect three input phases. Usually they come from an input machine, which reacts to surges in mains voltage. Each of them is followed by load wire 2, 4, 6. The input and output of the neutral wire are connected to the seventh and eighth terminals, respectively.
Electric current flows from the output phase terminals 2, 4, 6 to single-phase devices. Cables must be marked.
Important! The marking of the cores is carried out taking into account the colors, so that in the future the user does not make mistakes when laying them through machines, RCDs and further to the loads.
Instructions: connecting a three-phase meter
The sequence of actions is as follows:
- An overhead or underground cable is laid from the power line to the house to the input machine. This must be done by specialists.
- An electric meter is installed in the electrical panel along with other protective equipment. Depending on the number of consumers, machines with poles from one to four are fixed. To make the circuit more compact, you can use differential circuit breakers instead of RCDs.
- From a four-pole input circuit breaker, colored wires are connected to the input terminals of the meter.
- In the same sequence, the internal network wires are connected to the output terminals. The input and output connected to adjacent terminals must be the same color.
- Connecting a three-phase meter with an RCD. The phase and neutral wires are connected to the latter in the sequence corresponding to its circuit.
Before starting work on installing electrical wiring inside the panel, you should definitely check the disconnection and blocking of accidental switching on of voltage at the input. The serviceability of the insulation on the tool handles is also checked.
It is not allowed to connect a three-phase direct connection meter, the power of which is lower than that consumed by the home network. To do this, you need to first calculate the maximum load and select the appropriate device. It is advisable to purchase it with a power reserve.
Conclusion
The three-phase meter is connected to the home network directly. All models have the same connection diagram. It can be found in the device passport and on the back of the terminal cover.
A properly selected electric meter will help the homeowner save on utility bills. In order not to make a mistake with the choice, the first thing you need to do is find out which device is suitable depending on the electrical network connected to the house - three-phase or single-phase, and also what is the difference between such devices, how are they installed and what are their advantages and disadvantages?
If we consider a single-phase electricity meter, then it is used in networks whose voltage corresponds to 220V. In turn, the three-phase analogue is connected to the electrical network with voltage 380V. Moreover, the first type of meters is familiar to every owner of his own home, as it is used in apartments, office buildings, garages and other similar buildings.
Three-phase control devices were recently used only in enterprises, but increasingly they can be found in private housing construction. This was facilitated by the emergence of many household appliances requiring additional power. For this purpose, houses and apartments began to be connected to a three-phase electrical network, the energy supplied through which must be controlled by special devices for metering the electricity consumed.
Operating principle of three-phase meters
A three-phase electricity meter differs from a single-phase analogue in its ability to function in sufficiently powerful networks. If standard 220V electricity meters are installed in an electrical circuit with a power of no more than 10 kW, then three-phase devices operate with power loads of 15 kW and much more. Such multifunctional devices work equally well both in a standard household network and control the energy consumption of three-phase electric motors. In this case, standard monitoring devices of this type consist of the following structural parts:
- conductive winding;
- voltage windings;
- a worm gear that drives the dial;
- aluminum disk and magnet.
Standard induction energy meters used in a 380V network, such as Mercury, equipped with plastic housings, which protect all mechanisms from moisture or various types of contamination. Inside the case there are 2 cores around one of which a current winding is wound, connected in parallel to the network. In turn, a voltage winding is wound around another element, the turns of which have an increased diameter compared to the current tax. In the middle between the coils in the formed space, there is an aluminum disk, the rotation of which occurs through the fields created by the windings.
To ensure display of readings, the meter is located worm type mechanism, through which a mechanical pointer or an electronic display is connected to display data. In turn, the magnet is designed to regulate the functioning of the control device. All winding terminals are connected to the terminal contacts of the metering device and output to the phase. To prevent interference in the operation of the electric meter by the consumer, the outputs are sealed by representatives of the electricity supply company.
An important rule for purchasing any type of device for monitoring electrical energy consumption is the mandatory check that the device has all the necessary seals installed at the manufacturer. If such protective elements are not found, then the meter is unsuitable for its intended purpose and its installation has no practical significance.
Varieties of connection diagrams
First of all, the choice of a suitable connection diagram for a 380V electric meter depends on the type of control device. I would like to note that three-phase meters are capable of operating in standard 220V electrical networks. At the same time, all household electricity metering devices differ in the following connection diagrams:
- metering devices with direct connection;
- electricity meters with semi-indirect connection type;
- control devices with indirect switching type.
The direct-flow device for metering energy consumption is designed for current transmission not exceeding 100 A. Because of this, the use of such a device is limited in power, which is no more than 60 kW. The terminal contacts of such electric meters and the wiring holes are designed for connecting wires of small cross-section. In most cases, this is wiring, the cross-section of which varies from 16 to 25 mm square. Direct connection devices have a standard connection diagram indicated on the back of the electric meter cover, which does not cause any particular difficulties.
Three-phase meters with semi-indirect connection
Electric meters "Mercury" with a semi-indirect connection principle, they are connected to the 380V AC network through a transformer. Thanks to this, it becomes possible to meter electricity with high network power. At the same time, in the process of calculating the resources used, the transformation coefficient must be taken into account. Today, there are quite a lot of semi-indirect circuits, the most popular of which are the following options:
- transformer connection circuit according to the “star” principle;
- ten-wire connection;
- connection diagram using test terminal boxes;
- by combining current and voltage circuits.
Considering the disadvantages of a circuit with a semi-indirect connection, I would like to note difficulty in carrying out scheduled inspections energy sales regulatory authorities.
Direct connection of a three-phase device
The simplest connection method, which resembles a standard installation diagram for a single-phase meter, is the direct connection of an electricity consumption monitoring device. The main distinguishing feature of such devices is the presence of a larger number of terminal contacts than in single-phase analogues. In turn, the installation process of the three-phase Mercury device itself consists in a certain sequence of actions.
If planned installation of several consumers single-phase type, then they must be evenly distributed, for which they are connected through automatic machines from different phase conductors taken immediately after the electric meter.
Indirect method of connecting meters
If the parameters of the consumed loads of all devices exceed the rated current values passing through the electric meter, then an additional isolation current transformer is installed. Installation of such a device is carried out in a break in the power current-carrying wire.
On a current transformer there are two main windings. The primary circuit is made of a powerful conductive busbar, which is threaded through the center of the device and connected to the gap in the power supply conductors of electrical energy consumers. In turn, many more turns of wires are wound on the secondary winding, but with a smaller cross-section. This winding is connected directly to the electricity meter.
This method is much more complicated than the direct option and requires certain skills from a person. Therefore, if a person does not have confidence in his own electrician talents when connecting a three-phase electric meter through a transformer, then it is advisable to think about calling a specialist. In other situations this the problem is completely solvable.
- Three transformers are connected for each individual wire. They are mounted on the back of the entry cabinet. The connection of the primary windings is carried out immediately behind the input switch in the break of the phase power conductors. Installation of a three-phase meter is also carried out in a cabinet.
- A conductor with a diameter of 1.5 mm² is connected to the phase conductor before the transformer, the free end is connected to the second terminal contact of the electric meter.
- By analogy, the 2 remaining transformers are connected to the corresponding phase conductors on the Mercury electric meter at terminal contacts 5 and 8.
- From the secondary winding of the transformer device, conductors with a cross section of 1.5 mm² are connected to terminal contacts 1 and 3 on the meter. It is very important to maintain the correct phasing of the windings. Otherwise, the readings from the electricity consumption monitoring device will be incorrect.
- By analogy, the remaining windings of the transformers are connected to the corresponding contacts on the meter.
- The remaining 10th terminal contact is intended for connecting the neutral grounding bus.
However, when considering meters with indirect connection, I would like to note that they are more often used to account for electric current consumption in powerful high-voltage networks and not for domestic purposes.
Correct choice of three-phase meter
When choosing a three-phase electric meter, it is important to base it on the reliability, accuracy and durability of the device - the main criteria for a high-quality device for metering electricity consumption. In this regard, “Mercury” meters have proven themselves to be excellent, which are produced both with connection via a transformer and directly.
The manufacturer presents a line of both budget devices with an electromechanical electricity control system, and functional meters with an internal tarifficator capable of keeping track of different tariffs simultaneously. Modern counters "Mercury" equipped with self-diagnosis and the ability to connect to a personal computer. All devices have electronic seals and have a long service life of up to 16 years. Also, modern Mercury control devices have the following capabilities:
- measurement of active energy type;
- accounting for reactive energy;
- ability to control up to 4 different tariffs;
- the presence of a function that maintains an event log;
- quality control of electrical energy;
- additional interfaces.
The importance of saving energy is clear to absolutely everyone, and three-phase type meters cope well with the tasks assigned to them. New devices have program setting function, certain operating modes. If during the daytime the tariff is charged at one price, and at night at a different price, then a modern electricity monitoring device keeps records automatically.
Naturally, simply choosing a high-quality three-phase meter is far from enough. Every conscientious owner should understand the various connection schemes for such devices. After all, every person knows that an incorrectly connected electric meter to a three-phase AC network will show incorrect data and there can be no talk of any savings.
Since the electricity consumption of household appliances is small, single-phase voltage is used to supply electricity to homes. All electrical appliances, including the electricity meter, are connected to the electrical network using two wires. An increase in power of devices connected to the electrical network over 10 kilowatts requires a reduction in the load on the wires. This is achieved using three-phase voltage. In this case, the electrical power used is distributed between three wires when connecting “star” and four wires when connecting “star with neutral wire”.
To account for the power consumed in three-phase networks, special three-phase electricity meters are used. When working with electrical loads of low power, a galvanic connection is used, and for high powers, a transformer connection of these electricity meters is used. If currents are more than 100 Amperes and maximum power is more than 60 kilowatts, current transformers are used.
The meter is installed in a special design. Usually this is an electrical panel designed to be attached with several screws to a platform with an electric meter. As a rule, it is necessary to fix only three to four screws, which does not require a long time and does not cause difficulties.
- The installed electricity meter should not be operated in excess of the voltage and current values set for it.
The connection diagram for a 3-phase electricity meter is below.
Having securely secured the electric meter in the electrical panel and turned off the voltage, you can begin installation work on connecting the elements of the electrical circuit.
A power cable with four insulated conductors is used for connection. A circuit breaker is installed at the input, to which the power cable is connected. After the switch, phases A, B and C and 0 are respectively connected to terminals 1,3, 5 and 7 of the meter.
Connecting a digital electric meter is carried out with the obligatory observance of the phase sequence – A, B, C. Special devices allow you to determine the phasing. If the meter is incorrectly phased, it will display an error message. In this case, the connected wires change places.
The load is connected to terminals 2, 4 and 6, and 0 to the 8th terminal.
- The grounding of the electric meter is connected to the electrical panel housing, which must be grounded.
- If a three-phase network is used to connect both three-phase and single-phase loads, 0 must be grounded to avoid possible overvoltages. Overvoltages occur when the insulated 0 breaks.
The meter should be connected in strict accordance with the instruction manual, since the numbering of the terminals and the connection diagram itself may differ for different models, especially those released at different times. New models of electricity meters allow for remote data monitoring and therefore have a larger number of terminals.
Operation of the meter is allowed only after it has been checked and sealed by the relevant services.