On 15/11/11 23:32, Wayne Stallwood wrote:
Actually the point of reading the pulses from the meter is that the meter is pretty damn close to being 100% accurate in real terms and is 100% accurate in terms of what you are paying for.
Absolutely, but I can still verify the data coming from the CT [*] by manually checking the meter periodically. If there's a big discrepancy I can adjust for it (and possibly buy the OptiSmart if I need to), although if the CT measurements aren't accurate then any hope of sub-metering with extra devices around the house goes out of the window. (Also, for this reason I wouldn't want to just have pulse counting at the main meter and use the CT to sub-meter (eg) my server, because if the CT would give inaccurate reading at the main meter then it'll still be giving inaccurate readings at my server but I won't know about it.)
What I do like, is that by offering a device to read meter pulses it suggests that the manufacturer is fairly confident about the accuracy of their other kit.
[*] CT = Current Transformer = the bit you clip over your mains cable to measure the current, http://en.wikipedia.org/wiki/Current_transformer