How can I verify my electricity meter ?

[Martinco]

Are you sure you've got it on the main line into the board and not just on a circuit that doesn't have the geyser or pool pump on it ? Nothing else between the meter and the monitor ?

Yes Dave, Quite sure. I have installed this in my factory and have clipped the three pickups over the three incoming phases. But what worries me is that the monitor unit does not have a setting for 380 volts. It only goes up to 250 volt but if I run a 4 Kw motor with load it shows +- 4 Kw.
My logic tells me that it must make a difference if the voltage setting is 230 volt and should be 380 volt but I have emailed the manufacturer and asked these questions.
Just for another test I intend to switch off all other machines/geysers etc and only switch on the 10 mercury vapor factory lights at 450 watt / each and then see what reading I get.
Any idea what the power factor on these units are ? I.E. what should I add for the loss of efficiency ?

[AndyD]

But what worries me is that the monitor unit does not have a setting for 380 volts. It only goes up to 250 volt .......

Is this an American monitor? USA is 110v phase to neutral which gives around 230v phase to phase.

[Martinco]

Is this an American monitor? USA is 110v phase to neutral which gives around 230v phase to phase.

No apparently built for SA conditions but the manufacturer came back to me saying that it should be set to 230v as the phase to neutral is 230 v.

The sensors only pick up the magnetic field around each phase and uses that to do the calculation.

I shall monitor the readings and report back !

[Martinco]

On the same issue:

Does anybody know what the code is to enter into a prepaid meter to display the total amount of units used since installation ?
I asked the guy from the municipality but either he does not know or he does not want to tell me, and if the latter, Halloooo, what can I do with the info apart from verifying total consumption ? I cannot break the meter !

[Martinco]

Mine is pretty accurate. If I rig it to a line that has 3 x 100W bulbs on it, it shows a little over 300W, and my geyser element comes on and shows 3,012 W ( 3kW element ).

I have been monitoring the unit and no matter what voltage setting I set it to, I do not even remotely get the same reading as on the pre-paid meter so I am going to have a proper meter installed in the DB.
It seems this will be the only way to check.
By the way.......I had the guy from the municipality here and "Sorry.........iesh, the calibrating machine she is broken! "

[murdock]

pity you arent in durban i could have set up a recorder and done all the checks for you and supplied you with an accurate meter....

there must be a sparky up there who can advise you on these issues.

[Martinco]

there must be a sparky up there who can advise you on these issues.

I have contacted the owner of the building who is sending the sparky that did the job to come and check. ( and also install the second meter )
So....it is wait and see !

[AndyD]

On the same issue:

Does anybody know what the code is to enter into a prepaid meter to display the total amount of units used since installation ?

There isn't usually a code as such, depending on the make and model of meter you can often access this info by just scrolling through the display with the up/down buttons. It's possible to program most meters to determine what is available on the display, sometimes they are set not to show anything but the meter id code and the most recent consumption and that way they avoid confusing the meter reader. If this is the case you need an opto-coupler any an ORBIS compliant application to download the info to a laptop assuming they haven't password protected it.

I have been monitoring the unit and no matter what voltage setting I set it to, I do not even remotely get the same reading as on the pre-paid meter so I am going to have a proper meter installed in the DB.......

I've checked dozens and dozens of CT metering devices of many different ages and manufacturers and I can say I haven't ever found a metering unit that was inaccurate by more than 2 or 3 percent during a calibration test. That said I have found way too many that aren't operating correctly because of installation errors such as incorrectly installed CT's and incorrect parameter settings. The most common error I have encountered is incorrect settings for the CT ratios in the meter software. Sometimes these errors work in the customers favour, sometimes not.