Connection of a three-phase electricity meter

The electricity meter is needed primarily by the energy supply company, and the consumer is required to install it in the apartment, in the house, in the garage or in the country. In apartments, a mostly single-phase device is installed. The connection of a three-phase meter is carried out, as a rule, in private houses.

Many meters are installed long ago and require replacement. The main reasons for this are as follows:

• end of life;
• loss of measurement accuracy (below the second class);
• the need to install a multi-tariff instrument.

Installation of a new meter can be done with the help of professionals or on their own. There are no particular difficulties, but the rules should be followed.

Which counter to choose?

Previously, mechanical type (induction) meters were manufactured. Their release is still ongoing, the installation is allowed by energy supply companies. Old structures are being replaced by electronic-digital devices. Both options cope equally with their work, but mechanical ones withstand the effect of low temperature worse. It is important that the device passes the accuracy class, which should not be lower than the second.

How to connect a three-phase meter?

A three-phase electricity meter is connected from the corresponding supply network.

It is required in a house equipped with an electric boiler, machine tools, electric stove and other powerful equipment. At the entrance, a control cabinet with protective devices for one and three phases is installed. Input from an external network consists of 4 or 5 cores, where 3 current-carrying, neutral and ground wires are used. Grounding can be set separately.

A 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 with three current-carrying wires of the network L1, L2, L3 and the 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 schemes 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 device certificate. The connection of the three-phase meter "Energomer" is done according to the usual scheme described above.

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

Features in connecting a three-phase meter

Features of the procedure are as follows:

1. You must first purchase all the components for installation: switchboard, electric meter, automatic machines, UZO.
2. For safe maintenance of the meter, a three-phase automatic machine is required in front of it.
3. The external power cable is first connected to the input circuit breaker.
4. From the machine, three phases are connected to the meter, and after it, through the RCD, to the load.
5. When connecting the cable, you must not confuse the phase and zero conductors.
6. Grounding to the device is connected to the RCD.

Rules for connecting the electric meter

Since the meter is primarily needed by the energy supply company, all activities related to the connection are carried out with the participation of its representatives. Installation can be done with your own hands, but at the last stage you need to call the controller. When working, 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 needed so that the consumer can not change the connection diagram. After sealing, you need to get an act of acceptance on hand.

If the meter is installed without the participation of the power supply organization, it will not be considered a control device. This will be a conventional electrical device, like an RCD or an automatic machine.

Connection of the three-phase counter "Mercury 230"

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

• the ability to select the device according to the strength of the maximum and rated current, as well as the accuracy class;
• accounting for bi-directional energy consumption;
• the availability of event logs and indicators of electricity quality ;
• the interval between verification is 10 years;
• service life - up to 30 years;
• the presence of interfaces and a modem.

Wiring diagrams

The connection of the three-phase meter "Mercury 230", as well as all others, can be made directly to the mains 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 the three input phases. Usually they come from an input machine that responds to power surges. Each of them is followed by a load wire 2, 4, 6. To the seventh and eighth terminals are connected, respectively, the input and output of the neutral wire.

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

Important! Marking of cores is made taking into account the colors, so that in the future the user is not mistaken when laying them through machines, RCDs and further to the loads.

Instruction: connecting 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 input machine. This must be done by specialists.
2. An electric meter is installed in the electrical panel along 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, differential automata can be used instead of RCDs.
3. From a four-pole input circuit breaker, colored wires are connected to the input terminals of the meter.
4. In the same sequence, the wires of the internal network are connected to the output terminals. Input and output connected to adjacent terminals must match in color.
5. Connection of a three-phase meter with RCD. Phase and zero wires are connected to the latter in the sequence corresponding to its circuit.

Electrical Recommendations

Before proceeding with the installation of electrical wiring inside the shield, it is necessary to check the disconnection and blocking of the accidental inclusion of voltage at the input. It also checks the operability of the insulation on the handles of tools.

It is not allowed to connect a three-phase direct connection 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 margin of power.

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 instrument passport and on the back of the terminal cover.