DIY Callibrate Electrical Meter

[kenimpzoom]

Is there anyway I can check the callibration of my electric kwh meter?<br /><br />I dont trust the thing in the new house. And I dont really trust the electrical co. Kind of the old fox guarding the hen house thing.<br /><br />Seems like all I would need is a known constant energy user and a stopwatch and I could time how long it takes for the wheel to make one revolution.<br /><br />Will this work?<br /><br />Ken

 

[tommays]

Re: DIY Callibrate Electrical Meter

Well you could use a clamp on amp probe and check the total draw on each leg.<br /><br />And then do the math to work out amps to Kwh<br /><br />(VOLTS X AMPS)/1000 X TIME<br /><br /><br />tommays

 

[rwise]

Re: DIY Callibrate Electrical Meter

first I do not recommend this!<br />My brother had problems and tried to get his meter tested, they told him that the meter does not fail! His electric bill was outrageous, soooo, he went out with a 45 and shot it several times, then called in a power outage! long story short, they put in a new meter and 2 months later issued him a rebate for over charges.<br />As far as testing, I don't know the answer.

 

[sangerwaker]

Re: DIY Callibrate Electrical Meter

This was just on the local news here last night.<br /><br />tommays is right on about how to actually test the meter. Another test they mentioned on the news last night was to turn off the main breaker in the house and see if the wheel continues to turn slowly. If there is no current draw, the wheel should not move. They said a small percentage of the meters did and thus over-charged the customers.

 

[KaGee]

Re: DIY Callibrate Electrical Meter

Power company swares to me that the meters fail on the "slow" side. So they would charge less, not more. She said if they came out and changed meters my power costs would go up.

 

[divo]

Re: DIY Callibrate Electrical Meter

The only way I am aware of testing the power companies electric meter is to install a seperate one in the house yourself. You need something that will record over time. Putting an amp-probe in the panel wont be accurate enough unless you spend some cash and only give a realtime reading. I have installed several of these and they work very well. Do a search for "emon demon". They are a couple hundred dollars but there might be some cheaper ones out there. Are your electric bills higher that you think they should be? If so there are other things that can be checked before spending to much money.

 

[dogsdad]

Re: DIY Callibrate Electrical Meter

You could always turn off and unplug everything in your house, and turn on ten 100-watt bulbs, thereby presenting a 1 kwatt load to the meter. Then get out the stopwatch, run a little test, and do a little arithmetic. That should give you some kind of an idea of how accurate or inaccurate the meter is.

 

[Koda]

Re: DIY Callibrate Electrical Meter

found this page hope it helps<br />Luck Koda<br /> http://groups.google.com/group/misc...67f6380144aefd4?sa=X&oi=groupsr&start=0&num=3

 

[Koda]

Re: DIY Callibrate Electrical Meter

here is another page seems to be less complex<br />Luck Koda

 

[Koda]

Re: DIY Callibrate Electrical Meter

http://jidanni.org/geo/taipower/meter_en.html <br />sorry clicked to quick<br />Koda

 

[springhead]

Re: DIY Callibrate Electrical Meter

Hey Ken, whatever you do,dont call the electric co, they the electric co. will put in a new meter<br />and it will run faster than the old meter and your bill will go up.

 

[JB]

Re: DIY Callibrate Electrical Meter

You might not get an accurate reading with an Ammeter.<br /><br />In AC, voltage and current must be exactly in phase for the meter to give accurate readings. If your home has a slightly inductive or slightly capacitive load the meter will be inaccurate. Ask the power company to test the power factor of your load. If it is not exactly 1, you need a power factor compensator to balance the reactance. Only then can the meter be accurate.

 

[dogsdad]

Re: DIY Callibrate Electrical Meter

Dang, JB! It's been years since I've heard or read any mention of this. I like to think of it as 60 Hz impedance matching.<br /><br />Seems like when I went through school, an instructor was trying to tell us that if you had a device to compensate reactance in order to get a phase match, your power consumption would go down. I'm not sure I believe that or disbelieve that.<br /><br />What say you?

 

[JB]

Re: DIY Callibrate Electrical Meter

If the impedance of the house load does not match the equivalent resistance (Xl=Xc) you are buying Volt-Amps rather than Watts. <br /><br />Essentially, your house must be at resonance to use power most efficiently. <br /><br />If you are off resonance you will be buying more power than you are using.<br /><br />Power Factor states the relationship between inductive and capacitive load.

 

[levittownnick]

Re: DIY Callibrate Electrical Meter

A wattmeter reads true power. Volts times Amps times Power Factor (PF). Power Factor is never greater than 1, therefore if you have poor PF you will not be charged for all the Amps being consummed. However out of phase current will do no work therefore no benefit will be derived from this current. The wiring carring this current will still have to be of ample capacity to carry this out of phase current + the usable current. This imposes a burden on both the consummer and the supplier.<br /><br />Clamp-On Ammeters give a good "indication" of current but most have poor accuracy and are not suitable for use as a standard. Light bulbs wattage rateings are only approximate. If one desires to find the accuracy of a utility meter, a "certified" standard should be used. These certifications must be obtained periodically to insure accuracy. My employer pays about $100/year for each meter to maintain the certification of each wattmeter. (This is not a volentary expense.)

 

[--GQ--]

Re: DIY Callibrate Electrical Meter

Originally posted by dogsdad:<br /> You could always turn off and unplug everything in your house, and turn on ten 100-watt bulbs, thereby presenting a 1 kwatt load to the meter. Then get out the stopwatch, run a little test, and do a little arithmetic. That should give you some kind of an idea of how accurate or inaccurate the meter is.

Great idea, but a hot 100w light bulb draws more current than a cold 100w light bulb. Comparing the power consumption to the manufactor rating will not be accurate.<br /><br />Sometime the power companies bill you on your average usage and not on the actual reading for that month. You might want to give them a call about the matter. You might also want to compare your bills with a couple of your nieghbors.