Smart Meter Accuracy

We have a strange situation with a flat we own. The flat was empty while being decorated (by us) for 3 weeks. We know we used very little power. Yet the bill we got for that period was much higher than we would have expected.

The electricity supplier suggested we turned the power off for 15 mins and take the meter reading before and after to see if it was showing use. However, the meter readings only seem to be whole kWh so it would need to be a big fault to see a change in 15 mins. This aligned with what the smart meter console shows which is about 300W.

Instead we switched it to show Amps used and with the main circuit breakers off it showed about 1.3A. If this use was all day that would be 7kwh per day. Over 3 weeks this would be 10 times the actual bill we got. 

So this makes no sense. Why would a meter show use with the breakers off? And why would that use vary which can be the only explanation for the bill not being as high as an extrapolation of that 15mins suggest?

Parents
  • it showed about 1.3A. If this use was all day that would be 7kwh per day.

    Not necessarily - the power factor on some small electronic equipment (including things like PV inverters here) can be absolutely awful - I've often had the cheaper domestic "energy monitors" (the type that just have a clip-on CT and assume mains voltage) claim that things (especially on standby) are consuming many tens of  Watts, whereas a proper watt meter confirmed that the consumption was in reality a small fraction of that.

       - Andy.

Reply
  • it showed about 1.3A. If this use was all day that would be 7kwh per day.

    Not necessarily - the power factor on some small electronic equipment (including things like PV inverters here) can be absolutely awful - I've often had the cheaper domestic "energy monitors" (the type that just have a clip-on CT and assume mains voltage) claim that things (especially on standby) are consuming many tens of  Watts, whereas a proper watt meter confirmed that the consumption was in reality a small fraction of that.

       - Andy.

Children
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