The connection scheme for a three-phase meter is approximately the same as in the case of using a single -phase meter . Any house or apartment should be commissioned only after the installation of electric meters. According to the regulations, installation work can only be done by those people who have been trained, and they must have a permit for working in electric networks up to 1000 V.
But this is the installation of the counter, as for the installation of elements and connecting the meter directly to the loads, then these manipulations can be performed independently. Electricians only need to test the entire power supply system, and then connect the meter to the input to start all the electrics.
Basic Connection Requirements
All basic requirements and connection features are indicated in the EMP. But be sure to consider the following features:
- The meter must be installed with maximum protection against weather conditions. They must be installed in special boxes made of non-combustible materials. This box must be airtight, if it is necessary to install it on the street, and there must also be the ability to control the readings. Opposite the indicator should be clear glass.
- The meter should be installed at a distance of 80-170 cm from the ground.
- An electric meter is connected only with copper wires. Their cross section should correspond to the maximum current load. These data can be found in the technical specifications. If we are talking about apartments, then it is necessary to use wires with a minimum cross section of 2.5 square meters. mm In the case of a single-phase network, this is the maximum current of no more than 25 A. Today it is a very small value, since electrical appliances have a large power.
- The use of uninsulated conductors, as well as the presence of various branches and twists, is unacceptable.
- When using three-phase meters, it is necessary to check at least once a year.
Where to put the counter in the apartment?
If the meter is installed in an apartment building, then the place of its installation is completely and completely regulated by the existing project. It can be installed in the apartment, in a special shield or on the landing.
And in the event that it is mounted in an apartment, it is advisable to place it as close as possible to the front door. This is much more convenient since load connection is better. In addition, it will be easier for the supervisor to verify the evidence.
Installation of the counter in a private house
In the event that you decide to install an electric meter in a private house, you can use several options. It is allowed to install the meter on a pole - in the yard or next to it.
But it is best to install it indoors, as in this case, weather conditions will affect it to a lesser extent. But if the electricity supplying organization requires installation only on the street, you can install it on the wall of the house, in a special sealed box.
But the circuit breakers that protect various consumer groups must be installed in another box located indoors. It is imperative to take into account the fact that all wires are visually visible.
To enable work directly on the electric meter, it is necessary to mount a circuit breaker or circuit breaker in front of it. It must be sealed separately from the counter.
Connection diagram for single-phase meters
There are two types of electric meters for a 220 V household network:
- Electronic.
- Mechanical.
By type of electricity metering, they can be as follows:
- Single tariff.
- Two-rate.
There is no difference in connecting two-tariff and single-tariff, the connection diagram is the same. The difference is only in the internal components. But for the average consumer, this "filling" is simply not available.
There are two pairs of contacts on the terminal plate in any single-phase meter. On the same terminal block you can see a detailed connection diagram. In general, the connection diagram of the three-phase Mercury meter is practically the same as in the case of a single-phase meter, only there are more wires.
Connection Order
According to the diagram shown on the terminal strip, the order is as follows:
- It is necessary to connect the phases from the input cable and consumers to the contacts "1" and "2". First you need to connect the phase conductor of the loads, and after that only the input.
- To the contacts under the numbers "3" and "4" you must connect the neutral wires. Moreover, the contact "3" is supplied with zero water from the wire, and with "4" it is removed and goes to consumers.
The connection scheme of a three-phase electricity meter differs slightly, will be discussed below. The only difference is that a little more contacts.
A little bit about wires
All connections are made using wires, which must be stripped no more than 2 cm. It is advisable to refer to the installation instructions, all these data are available in it. In the event that a stranded wire is used, special terminals must be installed at its ends. They need to be selected by rated current and thickness. Be sure to crimp them using special pliers or pliers.
The stripped wire must be inserted all the way into the hole located under the platform with the contacts. Be sure to ensure that a piece of insulation does not get into the clamp. It is not permissible for a bare wire to peek out from under the body. The connection diagram for a three-phase meter is shown in the figure below.
Compounds are made in the same way as when using single-phase.
In other words, the total length of the bare wire should be as accurately as possible. On older models of electric meters, fixing is done with one screw, and in new ones with two. This is how the three-phase meters are connected. Features of connecting the meter are the same as when using a single-phase.
In the event that a new electric meter is being installed, it is necessary to first tighten the farthest fasteners, and after making sure that it is locked, fully tighten the second one. After about ten minutes, you need to tighten the contacts, as copper can take a little.
Three-phase meter connection
For the 380 volt network, three phases are characteristic, therefore, metering devices for it will be slightly different. It is immediately striking that there are a lot more contacts on electric meters. If you pay attention to the wiring diagram, it turns out that the outputs and inputs, as well as the neutrals are arranged in pairs. The connection diagram of the electric meter looks like this:
- If the phase with the letter "A" is connected to the first contact, then it is removed from the second.
- Phase "B" is connected to the 3rd contact and removed from 4. All the rules and the connection procedure are similar to those described above, only a larger number of conductors is used. First you need to clean and align them, then install in the connectors and tighten.
Be sure to install a circuit breaker in front of the meter that is sealed. After the metering device, a box with circuit breakers is mounted, from which the voltage is removed and supplied to the load. It is advisable to use a residual current device that will not allow electric shock.
Differences of a three-phase counter from a single-phase
Single-phase devices allow metering of electrical energy only if a two-wire network is used. Three-phase metering devices are used in 380 V networks of 3- and 4-wire type.
Single-phase networks are very often used to connect private homes, office premises, sleeping areas. In other words, those consumers whose power is not more than 10 kW. In some cases, it may be necessary to install and connect a three-phase direct connection meter.
And in this case, it is necessary to record the consumed electricity using single-phase meters. Their main advantage is simplicity of design, ease of installation, and most importantly, they are very convenient to use.
The use of three phases in everyday life
But the problem is that in everyday life a lot of electrical appliances of high power are used. That is why many homeowners prefer to transfer power to a three-phase network. If you believe the technical conditions that are available for connecting to networks, power from phase 3 and 1 is approximately equal in power.
But the advantage of using three-phase power is that you can connect various electrical appliances directly, without using various auxiliary devices. By using an efficient connection scheme for a single-phase and three-phase meters, high performance and reliability can be achieved.
Various heaters, induction motors, stoves can be connected to a three-phase AC network. This increases the efficiency of the electrical appliance.