The accuracy of the measuring instruments is guaranteed within a range of current values indicated by the manufacturer. In particular, below the minimum value the instrument is no longer required to measure with the prescribed accuracy. It is therefore necessary to pay attention to situations in which the current absorbed by the loads varies frequently including the values below the minimum current, since even if they are the cause of an effective energy consumption, the measuring instrument could interpret them as “no load” and therefore does not count this consumption. It follows that two measuring
instruments in comparison, if equipped with different minimum current, can also provide significantly different energy values.
Other information on this topic
Take a look to the Metering instruments and current transformers web page.
Make sure to visit em.lovatoelectric.com