Every month, people pay for electricity, the consumption of which is taken into account by an electric meter. However, often the amount of electricity consumed is much higher than the actual energy consumption. This calls into question the quality of the meter. Let's look at how to check the electricity meter at home.
Why do electricity meters lie?
During the changing seasons, electricity meters often overestimate their readings. These devices are lying. There are many discussions of such cases on various forums.
Some people claim that for one night of operation of the refrigerator, the energy meter counted as much as 4 kW - this is a lot. At a company that supplies electricity to apartments, residents are told that the meter works accurately. But engineers from the same enterprises openly declare that the meters are lying, and how they are lying. This is especially true for budget systems, such as the Mercury counter. He is often complained about.
The real picture is that to issueoverestimated indicators of the metering device can and with quite correct operation. The first reason is a decrease in voltage in the network due to the massive use of air conditioners or heating equipment. Household appliances change efficiency down if the voltage is below 220 V.
So, in order to achieve a certain task, an electrical appliance needs, for example, not 0.19 kW / h according to the passport, but from 0.25 and above. This picture can be observed with all household appliances. It turns out that the same consumer of electricity at different times on the meter will spend different amounts of energy, although it seems that everything is fine.
In this case, it is necessary to test metering devices so as not to pay energy companies what they themselves should pay for. The fact is that the electricity supplier is obliged to maintain the required parameters in the network. If the parameters are violated, then in Europe the delivery company pays for it.
When should the electricity meter be checked?
The meter should be checked in cases where there are violations in its operation, namely, a strong increase in consumption is noticed or, conversely, a sharp decline. With an emergency check, you should not delay, a quick reaction in this case will avoid serious fines and problems. Also, the check should be carried out when connecting any new equipment, if the energy consumption remains the same as it was. And one more situation is a decrease in real consumption, if the meter at the same timedid not change his performance in any way.
Also, the electric meter is checked once every year. Such timely checks can also help avoid serious problems.
Do you know the described situations? Then you should use simple tips on how to check the electric meter yourself. During testing, the device will be checked for self-propelled and error. You will need a stopwatch, multimeter, 100W light bulb and calculator.
Checking the correct connection
This is a very important point. It is important that the metering device is properly connected to the electrical network. This can be 220V or the industry standard 380V.
Single-phase meter
Single-phase meters are used in apartments, the network for such apartments is also single-phase. In this case, four terminals are used for connection. The correct circuit is the one where the phase wire will go from the electrical line to the first terminal of the meter. Through the second terminal, the line usually goes to the apartment. It is also considered correct when the neutral wire goes to terminal 3, and exits through terminal 4. How to check the electric meter at home for correct connection? Just count the terminals and see where and what goes.
Three-phase meter
For residents of private houses, a slightly different connection scheme is used, since in this case, most likely, a three-phase electrical energy metering device is installed there.
Only the number of cables and terminals changes in the diagram. In general, the connection principle is the same - the phase from the electric line is connected to terminal 1, and exits terminal 2. The second phase enters terminal 3 and exits terminal 4. The third phase goes to terminal 5, and exits the sixth. Zero connects to terminal 7 and goes to terminal 8.
Here's everything you need to know before checking the operation of the electricity meter.
Testing the self-propelled meter
What is self-propelled? Everything is very simple - this is accounting for energy, if at the current moment there is no consumption of it. That is, the meter can read the readings on its own, without the use of electrical appliances.
To check that the disk of the device does not rotate on its own, you need to completely turn off all the machines that are located in the electrical panel at the bottom of the device and serve sockets and switches. You must also turn off all electrical appliances.
How to check a home electric meter for self-propelled if there are no machines in the electrical network? It also happens that this check is even easier to carry out. All electrical appliances, as well as switches, are disconnected from the network. In this case, there should be no electricity consumption.
After turning off, it is recommended to wait about 10-15 minutes. Then a visual test is performed: if the LED on the front panel is flashing or the disk is spinning, then this device has failed the test. The owner has no choice but to check the correctness of the electricity meter in the management or service company.
If the device is working, then nothing will flash orrotate. The LED can blink once every 10 minutes, the disk should make one rotation within the same 10 minutes.
We consider the measurement error
So, during this test, it is necessary to calculate the error of the accounting system. For this, an incandescent lamp, a multimeter, a stopwatch, and a calculator are useful. It is best to use an electronic device as a multimeter.
The most common incandescent lamp is recommended as a load - the whole problem is that modern household appliances can adjust their power depending on the situation. As a result, nameplate power will not correspond to real values. If there is already an error at this stage, then the test result will not be accurate.
How to check the accuracy of the electricity meter
First of all, you need to measure the mains voltage, here you will need a multimeter. How to use this device, you need to know in advance. The number on the display of this measuring device is best written on a piece of paper.
Then, the light bulb current is measured. The tester is switched to the current measurement mode and connected to the lamp. Together with the current strength, the power of the light bulb will also be needed for calculations. This can be found out using a simple formula from a school physics course - voltage is multiplied by power. In addition, you should also calculate the resistance of the light bulb - the voltage is divided by the power.
Now it's time to move on toverification. Let's see how to check the electricity meter at home for accuracy. To do this, when the light is on, they measure how long it will take for the metering device to blink 10 LEDs or 10 revolutions of the disk. At the same time, it is necessary to control the voltage in the network. For example, the device can make 10 revolutions in 2 minutes, and the voltage can be 223 V.
Next, on the meter body, you need to find the value of its constant - it is indicated in pulses per kWh. Also, the value can be different. For example, the electronic counter "Mercury" has this data on the front panel.
Use formulas
Using the formula P=UU/R, the actual electricity consumption is calculated. This is done in order to find out how much the lamp actually consumes at the current moment.
To check, you still need to find out how much power was consumed during the check period, for example, let it be 2 minutes. To find out, the real consumption must be divided by the test time, in this case 120 s.
Check the error using the following formula: 1000 multiplied by the number of revolutions divided by the constant from the front of the device. For example: 100010/3200. The error is determined by subtracting the figure from the last step from the actual consumption. Further, all this must be multiplied by 100. If it turned out to be about 5%, then this is an insignificant error.
E=(PTA/constant number of pulses - 1)100%, where E is the valuepercentage errors, P - lamp power, T - time for which the counter will make one complete revolution, A - gear ratio of the meter.
Magnetization tests
Questions are often asked on the Web regarding the counters of the brand "Mercury", as well as "Neva" on the level of magnetization. The thing is that these devices are equipped with a special anti-magnetic seal. If they tried to stop this device with a powerful magnet, then this very seal will change its color. As a result, when checking equipment from the service and management companies, you can get serious problems.
If the device is not new and its model is simple, then the magnetization is checked with a needle. If it is drawn to the instrument panel, then it is magnetized. The level of magnetization decreases if the magnet is removed from the panel in two or three days. If the device does not even want to be demagnetized, then special demagnetizers are sold for this.
Here's all you need to know about how to check the electricity meter at home. This information will help you avoid unnecessary spending on bills and serious problems.
