Connection of a three-phase electricity meter

The electricity meter is needed primarily by the power supply company, and the consumer must install it in the apartment, in the house, in the garage or at the dacha. In the apartments is installed mainly single-phase device. Connection of a three-phase meter is usually carried out in private houses.

Many meters have been installed for a long time and require replacement. The main reasons for this are the following:

• End of life;
• Loss of measurement accuracy (below the second class);
• Need to install a multi-tariff device.

The installation of a new meter can be done with the help of professionals or independently. There are no special difficulties, but the rules should be followed.

Which counter should I choose?

Earlier, mechanical type meters (induction) were manufactured. Their release continues to this day, the installation is authorized by power supply companies. The old designs are replaced by electronic-digital devices. Both options are equally cope with their work, but mechanical ones can withstand the effect of low temperature. It is important, that the device passed on a class of accuracy, which should be not lower than the second.

How to connect a three-phase meter?

The connection of the three-phase electricity meter is made from the corresponding supply network.

It is required in a house equipped with electric boilers, machines, electric stoves and other powerful equipment. At the entrance is installed a switch cabinet with protective devices for one and three phases. The input from the external network consists of 4 or 5 cores, where 3 current-carrying, zero and grounding wires are used. Grounding can be set separately.

The connection of the three-phase meter is made to the mains directly or through step-down voltage and current transformers. They are installed in the power part of the circuit, when the power of the circuit is higher than that of the device. Direct connection is made with three current-carrying wires of the network L1, L2, L3 and zero wire N (figure 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.

Now many models are produced, the number of terminals and circuits of which may vary. For example, the connection of the 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. The connection of the three-phase counter "Energomera" is done according to the usual scheme described above.

Important! The power consumption is indicated in the passport on the meter. If it is exceeded, this can cause a malfunction of the device and even its ignition. To select a suitable counter, you must first calculate the total power of consumer devices. It is taken with a margin, if in the future the load is expected to increase.

Features in connecting a three-phase meter

Features of the procedure are as follows:

1. You need to pre-purchase all components for installation: switchboard, electricity meter, automatics, RCD.
2. For safe maintenance of the meter, it is required to install a three-phase machine before it .
3. The external power cable is first connected to the input automat.
4. From the machine three phases are connected to the counter, and after it, through the RCD, to the load.
5. When connecting the cable, phase and neutral conductors must not be confused.
6. Grounding to the device is connected to the RCD.

Rules for connecting an electricity meter

Since the metering device is primarily needed by the power supply company, all activities connected with the connection are performed with the participation of its representatives. Installation can be done by yourself, but at the last stage you need to call the controller. At work it is necessary to remember the following:

1. Installation is associated with strict rules and regulations that the management company requires to comply with.
2. Seals of the manufacturer and the power supply company are necessary so that the consumer can not change the connection scheme. After sealing, you need to receive an acceptance certificate.

If the meter is installed without the participation of the power supply organization, it will not be considered a monitoring device. This will be a normal electrical device, such as an RCD or an automaton.

Connecting the three-phase meter "Mercury 230"

Frequently installed counter "Mercury" is characterized by many different functions. It measures the reactive energy in both directions. Various modifications allow calculating energy at one and several tariffs, as well as storing information for a long time of operation. Main characteristics of the meter:

• The possibility of selecting the device by the force of the maximum and rated current, and also by the accuracy class;
• Accounting for bi-directional energy consumption;
• Availability of event logs and power quality indicators;
• The interval between verification is 10 years;
• Service life - up to 30 years;
• Presence of interfaces and modem.

Connection diagrams

Connection of the three-phase meter "Mercury 230", as well as all the others, can be made directly to the network wires or through current transformers, if there is not enough power. There are 8 terminals for connecting the cores. 1, 3, 5 terminals are used to connect three input phases. Usually they come from the input automaton, which reacts to the jumps of the mains voltage. Each of them is followed by a load wire 2, 4, 6. By the seventh and eighth terminals, respectively, the input and output of the neutral wire are connected.

The electric current flows from the output phase terminals 2, 4, 6 to single-phase devices. Cables must be marked.

Important! The marking of the veins is made taking into account the colors, so that later the user does not make mistakes during their laying through automatic machines, RCDs and further to loads.

Instruction: connection of a three-phase meter

The sequence of actions is as follows:

1. From the power line to the house, an air or underground cable is laid to the automatic transmission. This must be done by specialists.
2. An electric meter is installed in the electrical panel together with the rest of the 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 machines instead of RCDs.
3. From the four-pole input automaton, colored wires are connected to the input terminals of the counter.
4. In the same sequence, the internal network wires are connected to the output terminals. The input and output connected to adjacent terminals must match in color.
5. Connecting a three-phase meter with an RCD. The wires are connected to the last phase and zero wires in a sequence corresponding to its scheme.

Recommendations of electricians

Before proceeding with the installation of the wiring inside the panel, it is imperative to check that the input voltage is accidentally turned off and blocked. Also check the integrity of the insulation on the handles of tools.

It is not allowed to connect a three-phase direct input meter, whose power 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 reserve of power.

Conclusion

Connecting a three-phase meter to a home household network is done directly. All models have the same connection scheme. It can be found in the instrument's passport and on the back of the terminal cover.