Meters disagreeing

[big-all]

Two-wit - two-woo?

brilliant just brilliant lmao

 

[bhm1712]

I would have thought that the OWL wasnt calibrated either, I would expect the Actual meter to be calibrated to within 1 or 2 %? I know at work we calibrate ours to 0.5% for digital and 2% for analogue in terms of accuracy but i doubt the electricity companies go that far...or do they?

 

[stillp]

OFGEM state the usual accuracy to be +-2%.
http://www.ofgem.gov.uk/Markets/sm/...ctsheet_MeterAccuracy and BillingDisputes.pdf
EDIT: 2% is for gas meters, for electricity it states +2.5% and -3.5%

 

[westie101]

In the nationalised days we went for far greater accuracy that the limits available, usually within 0.5%

 

[stillp]

In the nationalised days we went for far greater accuracy that the limits available, usually within 0.5%

What accuracy do you expect today Westie?

 

[JohnW2]

I would have thought that the OWL wasnt calibrated either, I would expect the Actual meter to be calibrated to within 1 or 2 %? I know at work we calibrate ours to 0.5% for digital and 2% for analogue in terms of accuracy but i doubt the electricity companies go that far...or do they?

That may be true, but it's not difficult to manufacture and calibrate pretty accurate measuring devices these days, so I would not be surprised if the OWL were pretty accurate in terms of current measurements, quite possibly not appreciably worse than any other non-contact current measurement device. However, as I keep saying, one of the greatest problems is that it is only a current measuring device, and therefore cannot possibly be expected to be as accurate or reliable in the field at presenting 'kWh' figures in comparison with a proper kWh meter, which does it properly.

Kind Regards, John.

 

[westie101]

What accuracy do you expect today Westie

Not dealt with metering for a long time, but I would not expect it is any different

 

[SimonH2]

Also, I have noticed often how the OWL meter is showing current, which the L&G meter says there is none. Is the anti-creep mode the reason for this?

Current or power - they are two different quantities.

It is actually very easy to get a basic monitor like the Owl to show a reading while a real power meter shows none. Just connect an inductive or capacitive load and you'll get current, but no real power - the power meter is correct, the current indicator is misleading. When you have "no load" on, you probably have a number of small loads running - power supplies for various stuff - and these are often very poor power factor when unloaded (eg a transformer-rectifier PSU is mostly inductive with no load).
Recently, in a letter to Which? someone commented that after switching everything off, his boiler was "taking 40W" according to one of these monitors and commenting that this didn't seem very green I bet it had a transformer-rectifier PSU and was just presenting an inductive load.

I believe this is where some of the old wives tales about chargers and stuff taking the same power when not charging your phone as when it is - someone had measured the current, knows f**k-all about electricity, and declared it to be taking power.

hence why it is called a monitor not a meter.......

Well, to be fair, 'monitor' usually implies some sort of measurement device which measures continuously, or undertakes a continuous series of measurements, rather than necessarily implying anything about accuracy (some 'monitoring devices', particularly in safety-critical areas, can be extremely accurate) ....

"Indicator" comes more to mind.

 

[JohnW2]

hence why it is called a monitor not a meter.......

Well, to be fair, 'monitor' usually implies some sort of measurement device which measures continuously, or undertakes a continuous series of measurements, rather than necessarily implying anything about accuracy (some 'monitoring devices', particularly in safety-critical areas, can be extremely accurate) ....

"Indicator" comes more to mind.

Indeed - 'indicator'would seem to be a very good ford for a device which gives an indication of the magnitude of a quantity, rathere than necessarily an accurate measurement thereof.

However, to repeat what I've said before, I suspect that these OWL-like devices are probably as good as many non-contact devices at measuring current - but their conversion to the Energy (kWh) which they display is very iffy! So, maybe they qualify as current meters but energy indicators

Kind Regards, John.

Kind Regards, John