Replacing an electricity meter in an apartment

Refrigerators, washing machines, computers and televisions are just a small list of the main electrical appliances that we use every day. And such devices every day becomes more and more. And this requires not only an increase in the power of energy devices, but also their proper accounting.

An increase in the load leads to the fact that the previously installed devices for metering the consumed electricity, which had an accuracy of 2.5, are no longer capable of their duties, as a result, the calculation carried out by them comes with a significant error. That is why many people quite acutely face the question of how to replace an electricity meter in an apartment. So how do you replace this appliance? Let's get it together.

to contents ↑

How to choose an electricity meter? Classification

Before you buy a counter, you need to understand its structure and principle of operation. We will not delve into the technical characteristics of this electrical appliance - we only outline the main parameters that are worth paying attention to.

Induction and electric meters

Induction models are equipped with two coils - voltage and current. The magnetic field of the coils contributes to the rotation of the disk, which sets in motion the mechanism for calculating the energy consumed. The more electrical appliances are connected, the higher the voltage and current, the faster the disk rotates and the counter reads increase.

The main advantages of induction meters are - reliable operation and long service life (up to 15 years).

Important! Mechanical (induction) meters are the most popular.

Electronic meters

Electronic devices appeared much later. They do not have moving elements, and the energy consumption in them is calculated using semiconductors or microcircuits. Voltage sensors transmit indicators of the volume of electricity use.

Such meter models are more expensive than mechanical ones, but their readings are more accurate. In addition, the following advantages can be distinguished from the additional advantages of electronic meters:

• Easy to read data - the presence of a digital indicator.
• The possibility of multi-tariff accounting.
• It is difficult to steal electricity.

Important! Of the main disadvantages, high cost and a limited period of use can be distinguished.

Single phase or three phase meter?

As a rule, single-phase meters are used to power private houses and apartments. The rated power of household networks with a voltage of 220 V is about 3-7 kW. Given that 1 kW of power corresponds to a circuit current of 4.5 A, it is possible to calculate the current for which a single-phase device is designed - 13-32 A.

Three-phase devices are widely used to account for the consumption of electricity in industrial enterprises, cottage villages, municipal institutions, where input is permissible only for a three-phase system.

A good three-phase device has the following characteristics:

• The presence of a tariffifier inside is a time and date metering device that forms a load schedule, moreover, it can manage tariff transitions.
• The presence of a built-in power profile - with a breakdown by time remembers the largest power for a certain period.
• The presence of a communication interface for transferring data to a computer or communication center.
• The presence of an event log for recording increases and overvoltages at each phase, changes in active and reactive energy, voltage dips and prolonged lack of power.

In addition to the above parameters, when choosing an electricity meter, the following should be considered:

• Accuracy class (0.2-2.5%) is able to determine measurement errors. For apartments and private houses, the accuracy rate should be at least 2%.
• Connection method. Electricity meters can be directly connected or connected via transformers. Counters for a current that does not exceed 100 A are connected directly. In the event that the load is greater, the device is connected via a transformer with a secondary current of 5 A.
• The number of tariffs. The two-tariff device allows you to save on payment: during the day - at one rate, at night - at low prices.

Important! Users of such devices find profitable solutions, for example, launching a washing machine at night, when the price of electricity is half as low.

• The voltage class of the measuring apparatus is 100 V or 200/300 V. If the apartment is powered by a high-voltage transmission line, a device with a secondary voltage of 100 V is installed, which is supplemented by a current transformer.

to contents ↑

General requirements for the installation of an electric meter

Before replacing the electricity meter in the apartment, careful preparation of the room where the meter is installed is necessary. The durability and accuracy of this device is affected by many indicators:

• All kinds of vibrations.
• Temperature fluctuations.
• Humidity level.
• The composition of the surrounding air.

Among the prerequisites for the placement of counters are the following:

• The room must be dry.
• Permissible temperature conditions should be within + 5 ° С to + 40 ° С.
• The surfaces on which the meter will be located must have an acceptable degree of rigidity, not vibrate, resist deformation, and not shift.
• Allowed the placement of equipment on wooden, metal and plastic panels.
• Mounting must be exclusively on a vertical surface.
• The distance from the measuring device to the floor should be approximately 80-170 cm, the most optimal placement is at eye level.
• The slope of the device should be no more than 1 degree, otherwise - the error of readings increases (for mechanical models).
• The size of the niche, cabinet, shield where the meter is mounted is selected in such a way that access to the device and reading of readings is not difficult.
• When connecting the wires, it is necessary to strip at least 12 mm.
• It is necessary to provide for the presence of automatic device switches - they will be needed in the future when repairing or replacing the meter.

to contents ↑

Procedure for replacing the meter

In order to change the electricity meter in the apartment, you must adhere to a certain sequence.

Single phase

For the installation of an electric meter, you can buy a ready-made electrical panel that is equipped with the necessary elements. The second option is to buy all the components separately, namely:

• Directly the counter itself.
• Din rail.
• Metal / wooden / plastic box for equipment placement.
• Three-core cable with a diameter of 3 mm.
• Circuit breakers.
• Stainless steel screws that have a wide hat or, as an option, plastic dowels.

The procedure for replacing the electricity meter is as follows:

1. Distribute all necessary equipment in the shield. Such a “fitting” will help to understand whether the box is suitable for the dimensions and whether there are any difficulties during maintenance and operation of the device.
2. Mark out the places for the device and din rail. According to the markup made, fasten the elements.
3. Secure the circuit breakers to the rail.

Follow the wiring diagram as follows:

• Bring the phase to the circuit breakers of consumer electrical appliances located in the room.
• Determine the phase location from the device diagram. To output the phase to different machines, cut the cable sheath, remove the red and brown wires. Measure the segment, depending on its location (vertical / horizontal).
• Strip the wire that was removed from the cable by 20 m, insert the terminal and fix it with fasteners. On the machine side, strip the wire no more than 10 mm.
• Form U-shaped jumpers from the wires, then strip the ends and connect the circuit breakers located next to the system.

Important! It is necessary to check that when connecting the wires lay down without overlapping, otherwise the connection points will warm up.

• The next step after connecting the phase is to output zero - for this, use a wire of any other color.
• Measure the required length of the wire from the copper plate to the counter - the terminal for zero, as a rule, is the first terminal on the right or fourth on the left.
• Strip wires for zero and connect on both sides.
• After connecting the meter, attach the shield to the wall - mark the wall, drill holes and screw the shield with screws.
• Install grounding. Steel shields must be grounded according to the scheme: counter / shield / contact plate. Shields that are made of non-conductive material should be grounded immediately to the plate.

Three phase

In places with a high energy consumption, measuring instruments with a three-phase system are installed. Such devices at the output do not give out 220 V, but 380 V, which is necessary for the operation of some production equipment.

Such meters exclude voltage drops in the room where they are installed, as well as in neighboring buildings. Three-phase devices are best installed in special panels that have a platform and fixation on 3 screws. Installation of equipment is similar to the installation of a single-phase meter:

1. The power cable has three phases, the fifth grounding conductor and zero entering the electrical panel. Connect the yellow phase to the first contact, the red one to the fifth, the green one to the third. When connecting the phases, he acts very carefully so as not to make a mistake. Phases must be determined using a special device. After connecting one phase, check the meter for errors. Proceed in the same way until all wires are connected.
2. From the second, fourth and sixth contacts, remove electricity.
3. Zero falls on the seventh, eighth contact.
4. Fix the grounding conductor in a special bus. Connect zero to the ground - this will protect the network from overvoltage.

Important! New models of electric meters are equipped with an add-on that connects the system of remote transmission of readings. Such functionality causes additional contacts.

to contents ↑

Stock footage

As you can see, assembling and replacing an electricity meter in an apartment is not the easiest thing. During the installation process, it is necessary to competently and carefully approach the connection of wires. The developers of electric meters indicate on the cover of the block a detailed wiring diagram to be followed.