The 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. In apartments, a single-phase device is installed mainly. The connection of a three-phase meter is carried out, as a rule, in private homes.
Many meters have been installed for a long time and need to be replaced. The main reasons for this are:
- end of 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 on your own. There are no particular difficulties here, but the rules must be followed.
Which counter to choose?
Previously, mechanical type meters (induction) were manufactured. Their release continues to this day, the installation is allowed by energy supply companies. Electronic-digital devices are already replacing the old designs. Both options are the samecope with their work, but mechanical ones withstand the action of low temperature worse. It is important that the device passes the accuracy class, which must be at least the second.
How to connect a three-phase meter?
The three-phase electricity meter is connected from the corresponding mains.
It is required in a house equipped with an electric boiler, machine tools, an 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 cores, 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 section of the circuit when the power of the circuit is higher than that of the device. A direct connection is made with three current-carrying wires of the network L1, L2, L3 and a neutral wire 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.
Now there are many models, the number of terminals and the diagrams of which may vary. 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 circuit indicated in the instrument's passport. Three-phase connectioncounter "Energomera" 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, it can cause the device to fail and even catch fire. To select a suitable meter, you must first calculate the total power of consumer devices. It is taken with a margin if the load is expected to increase in the future.
Features in connecting a three-phase meter
Features of the procedure are as follows:
- You need to pre-purchase all the accessories for installation: switchboard, electric meter, machines, RCDs.
- For safe maintenance of the meter, it is required to install a three-phase automatic machine in front of it.
- The external power cable is first connected to the input machine.
- From the machine, three phases are connected to the meter, and after it, through the RCD, to the load.
- When connecting the cable, do not confuse the phase and neutral cores.
- Ground to the device is connected to the RCD.
Rules for connecting an electric meter
Since the meter is primarily needed by the power supply company, all actions related to the connection are carried out with the participation of its representatives. Installation can be done by hand, but at the last stage you need to call the controller. Keep the following in mind when working:
- Installation involves strict rules and regulations that the management company requires to comply with.
- Fillings neededmanufacturer and power supply company so that the user cannot change the wiring diagram. After sealing, you need to get an acceptance certificate in your hands.
If the meter is installed without the participation of the energy supply organization, it will not be considered a control device. It will be an ordinary electrical device, like an RCD or an automatic machine.
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 at one or several tariffs, as well as memorize information for a long time of operation. Counter main features:
- the ability to select a device by the strength of the maximum and rated current, as well as by accuracy class;
- accounting for bidirectional power consumption;
- availability of event logs and power quality indicators;
- 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 the others, can be done directly to the network wires or through current transformers if there is not enough power. There are 8 terminals for connecting wires. 1, 3, 5 terminals are used to connect three input phases. Usually they come from an introductory machine that responds to jumps.mains voltage. Each of them is followed by a load wire 2, 4, 6. The seventh and eighth terminals are connected to the input and output of the neutral wire, respectively.
Electric current is supplied from the output phase terminals 2, 4, 6 to single-phase devices. Cables must be marked.
Important! The cores are marked taking into account colors, so that in the future the user does not make mistakes when they are laid through automatic machines, RCDs and further to loads.
Instruction: connecting a three-phase meter
The sequence of actions is as follows:
- From the power line to the house, an overhead or underground cable is laid to the input machine. This must be done by specialists.
- The electric meter is installed in the electrical panel along with the rest of the protective equipment. Depending on the number of consumers, automatic machines with poles from one to four are fixed. To make the circuit more compact, you can use differential automata instead of RCDs.
- From the four-pole input machine, colored wires are connected to the input terminals of the meter.
- In the same sequence, connect the wires of the internal network to the output terminals. Input and output connected to adjacent terminals must match in color.
- Connecting a three-phase meter with RCD. The wires of phases and zero are connected to the latter in the sequence corresponding to its scheme.
Electrician recommendations
Before starting installation workelectrical wiring inside the shield, it is imperative to check the disconnection and blocking of accidental switching on of the voltage at the input. The insulation on the tool handles is also checked for good condition.
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 must first calculate the maximum load and select the appropriate device. It is advisable to purchase it with a power reserve.
Conclusion
Connecting a three-phase meter to a home household network is done directly. All models have the same wiring diagram. It can be found in the device data sheet and on the back of the terminal cover.
