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fcfcfc 08-10-2010 12:13 PM

Is my electric meter correct???
Have a DCSi IMT-3 on my residence. I have been "feeling" that the amount of KWH I have been using is more than it ought to be. SO, to make a long story short, I did a precise load measurement over ~36 hours using a Watts Up pro against the meter. In short, the house meter ran 10.4% more KWH with periods as high as 17% more. I am trying to "dig" into the causes and was trying to find more info on the meter. There is a link on this site, but it is outdated. DCSi is also now called Aclara.
Anyway, I need to get to the bottom of this. I have had this meter on my house for approx 8 years, and if it reading 10% high, that will add up to about 1000 dollars over the period, assuming a factory defect etc..
Any thoughts appreciated...


PaliBob 08-10-2010 12:51 PM

Bill, Welcome to the Forum
What is your location? Are you in Canada?

If you can get a $1000 refund due to a faulty power Company Meter please tell us.

What does your Power Company say?

moondawg 08-10-2010 01:08 PM

If I was the power company, the first thing I would ask is: "Where did you get your wattmeter calibrated?"

All we have now is 2 devices of unknown calibration status that are claiming 2 different numbers.

ETA: Is this the type of device you're using?

It would be nearly impossible to make an accurate comparison using one of these devices.

fcfcfc 08-10-2010 01:14 PM

Is my electric meter correct???

No, USA.. Have not approached the utility yet. I am now in the process of trying to explain the difference going under the assumption the residence meter is not in error. I am waiting for a return tech call from Watts Up where I need to get into the "nitty gritty" of the pro meter. Of particular interest to me is how it is handling inductive loads regarding current and voltage offsets in time, which is needed to calculate "power company" calculated KWH's.
In short, I am taking a Devils Advocate approach, until I run out of logicial explanations.


fcfcfc 08-10-2010 01:27 PM

Is my electric meter correct???

Yes, that is the series.... Again, I need to understand how it is doing what it is doing, both devices, and then look at the error difference. The difference is really a question of degree, 1% VS 100% would be very different situations...


Yoyizit 08-10-2010 04:17 PM

Re: 10 % high.

I have read where car dealers hide a 5% overcharge in many places rather than a single 50% overcharge because 50% is hard to dismiss as a computer error, a round off error, an honest mistake, etc.
I just got notice of a lawsuit involving Subaru. The plaintiffs alleges that the odometer reads 5% high so the mileage warranty expires sooner. Subaru admits no wrongdoing. I always wondered why my car doesn't show tenths of a mile on the counter and other cars do.

If your elec. meter is specified to be accurate within 2% you need to rent/buy a wattmeter or voltmeter/ammeter the calibration of which is traceable to NIST and accurate within better than 0.2% to 0.4%. Check your meter at minimum and maximum power levels. Max. levels are seldom but more money is to be made by overcharging at this level.

An honest error will be in favor of the PoCo half the time. Not even "60 minutes" seems to understand this.
If you and your neighbor are both being overcharged the likelihood of this happening at random is (1/2)^2 = 1/4. With you and 2 neighbors being overcharged the likelihood is (1/2)^3 = 1/8.
The more meters you measure the stronger your case.

If you find you are being overcharged and you say it out loud in some countries you will be immediately arrested. In the US they will find more sophisticated methods to shut you up and still stay out of the newspapers.

Read the Balek Scales by Heinrich Boll before you proceed, or don't proceed. Ignorance can be bliss.

nap 08-10-2010 04:23 PM

You could have a current leak that would account for the difference (presuming both meters are equally accurate). If you have a ground fault that is of high enough resistance, it would simply use power but provide no benefit nor would it trip the breaker.

If there has been a nail driven through a wire but does not make good enough continuity between the hot and ground or neutral wire, you could have current flow. If you have an underground wire that the insulation has been compromised will cause the same problem.

Not saying it is the problem but it is one possibility and it would not be the POCO's fault or liability.

fcfcfc 08-10-2010 04:46 PM

Is my electric meter correct???
Hi All:

To give you some insight, I have "a box" connected behind my normal main breaker that has a duplex and separate 15A breaker. It has to do with my backup power config. What I did for the test is to throw the main off and plug the Watts Up into the box, then selected loads into the Watts Up box via power strip. This way all the homes internal infrastructure was eliminated. The wire from the "box" runs just a few feet and connects right to the AL's after the meter base. So the test is very controlled. While I was running the test, I just ran the house on backup power, totally separate from the test and house meter. My original "quest" when this started was to look for "devices" in the house that were using more power than they should be, which I was suspicious of because I seemed to be using more elect than I should be. I am in the RE business and sciences and I have a very good "feel" for things like that, systems, etc.. SO, my original goal was not to find a "bad" meter but one or more loads operating out of spec. But with that said, it is logical to test the very device that is being used as the standard measure for my consumption in the first place...
Hope that is not to confusing....
Thank you for the responses so far...


kbsparky 08-10-2010 05:37 PM

Care to post a picture of that so-called "box" of yours?

fcfcfc 08-10-2010 06:01 PM

Is my electric meter correct???

I can post a pic but I have to take one first... All that it is, is an Tripplite IBAR2-6 that runs behind the main. Normally I have a 13W CF and 102DB Pizeo Woorbler plugged ito it and the device is off. When power goes out, I throw the main, turn on the "screamer" as I call it, and then engage the backup power. I really designed it as an effective way to know when the grid comes up, via an audio and visual alert. It's creation had nothing to do with power testing. It just happens to lend itself to this application test.


nap 08-10-2010 06:16 PM


I have "a box" connected behind my normal main breaker that has a duplex and separate 15A breaker. It has to do with my backup power config. What I did for the test is to throw the main off and plug the Watts Up into the box, then selected loads into the Watts Up box via power strip.
where is the breaker for this gizmo you have connected in relation to the main breaker in your main panel? Is it labeled "service disconnect"

so, we are still concerned with the accuracy of the two meters.

If you believe you have a problem, call the POCO and ask them if they will swap out the meter due to the discrepancies you have discovered. Once they install the new meter, check it again.

just an FYI: even if there is a overcharge by the POCO currently, you obviously have no proof of when it started so seeking payment for the last 8 years is not realistic. Not only that, most likely any applicable statute of limitations will only allow you to go back a couple years or so.

moondawg 08-10-2010 06:30 PM

Another point: what was the total energy consumed during the 36 hour test?

Is this a digital meter, or one of the old analog ones with the dials that spin around? If analog, you'd have to add your "observation error" in addition to the meter error.

fcfcfc 08-10-2010 06:31 PM

Is my electric meter correct???

Yes, that is correct. There is no magic here or misunderstanding on my part. Being an application of measurement, it is open to the question, "who has the correct 12 inch ruler".
You are probablly correct on payment, and the only way you could even begin to get a retro is to have the meter independently evaluated for the "problem", and if you were lucky, depending on the EXACT defect, etc., it may point to an original problem.... granted, allot of IF's...
But the cart is way ahead of the horse here... I am still waiting on the tech call back to have my first discussion, and will not contact the utility as long as there are roads left to be explored by me first....
I think the answer may lay in inductive loads and the 1 sec sampling rate, maybe... it all depends on how the electronics works....

The total house meter KWH was 13.1 KWH (tenth's estimated)
The Watts Up at 11.88 KWH
Difference 1.22 KWH ~10.3% more...


nap 08-10-2010 06:50 PM

you can do what you want but I doubt you will see anything from the POCO.


I have been "feeling" that the amount of KWH I have been using is more than it ought to be.
So, how long have you had this feeling (which isn't quite acceptable as evidence of anything)? If it was a recent epiphany, then maybe something changed. If you had this feeling for 8 years and failed to mitigate your damages, you will get nothing more than you can prove.

Either way, proving a loss for any length of time not actually measured and documented is virtually impossible. So, as it stands, you can argue you were overcharged 1.22kWH. If you fail to mitigate the losses, your total claim comes to 1.22kWh. If you get the meter replaced, your losses are 1.22 kWh.

fcfcfc 08-10-2010 07:07 PM

Is my electric meter correct???
1 Attachment(s)

Again, this is not a power company "witch hunt". That's not where it started and that's not where it is now....

Regarding my original post, I did not say the utility would be liable for 1000 USD over charges. In our world today, it is near IMPOSSIBLE for any "DAVEY" to get money from any "GOLIATH" even if the WHOLE truth is on Davey's side.
The only way Davey has a chance, is if there is some profit edge to be had by exposing the truth, that another Goliath is interested in....

The .jpg I attached is just the visual readings I took over the period....


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