So, you are fed up with your high power bill and you have decided that there has definitely got to be something wrong with your meter and you have requested a meter test. In this section I am going to cover what happens when request a meter test and your watthour meter is tested. The steps that it goes through and what the results of the watthour meter test mean. Hopefully, this will help you better understand what is going on when the utility tests your watthour meter.
You have called the power company because your power bill was too high and now the meter tech has arrived at your house to test your watthour meter. Maybe he talks to and explains what is going on with the meter test and maybe not. Some utilities do onsite watthour meter testing and others take the meters into their offices to test them and install a new one. Sometimes customers insist that their meters be changed as well after the meter test.
So, let’s say that the meter tech is going to test the meter on the premises and they take the meter and put it in a machine to do the watthour meter test that may or may not be connected to a computer and makes all kinds of noises. The meter tech watches the disk of the watthour meter spin or watches the display on the meter during the meter test and in about 2 minutes they tell you that the meter is just fine and that it tested somewhere close to 100.0%.
Maybe you are happy with his answer about the meter test and maybe you are not. Here are what the results from the meter test mean and what is actually going on during the meter test. On the nameplate of the meter is information that is used during the meter test. The test board has to be set up properly in order to test the meter properly and this meter nameplate information is important.
There is the Kh and there is also a TA which stands for test amps. The meter tech will input this information into the test board. Once the information is in the test board know what to do. But what is it doing? The test board has an software that tells it to put a known load through the meter over a known period of time. The load is based off of the nameplate of the meter and comes from the manufacturer. For most 2s meters that are in most residential homes the test amps is 30. This means that the manufacturer says that if the meter is tested at 30 amps and at 10% of 30 amps, which is 3 amps, the meter is accurate across its rated operating range. These tests are called the full load and light load tests respectively.
So, how do you know that you can trust this test board that the meter tech is using to do the meter test? After all, they are with the big scary electric company! The test boards have internal standards that have to be tested yearly depending on what state you live in. Not only do they have to be tested but they must be certified as well. This is how you can be sure that the meter test is accurate.
Here are two of the most common meter testers out there. The one on the left is the RFL 5800 and was made by Radian. It is no longer being manufactured but there is a company called Accurate Calibrations who still works on them and keeps them running. The one on the right is a WECO 2150. This model is still in production today.
On a final note, I would just like to speak to the engineering marvel that electric watthour meters are. They are very accurate and are not very prone to failure. They typically never fall outside of about 2% of their calibrated value. Which means that if for some crazy instance there ever was a problem with your meter that was causing the bill to be high (which by the way I have never seen in the tens of thousands of meters that I have tested), it would probably be only about 2%. This would mean that if your average bill is $100 then the month that the meter is off it would be either $98 or $102.
