Question

An ampere-hour meter, calibrated at 210 V, is used on 230 V circuit and indicates a consumption of 730 units in a certain period. What is the actual energy supplied ? If this period is reckoned as 200 hours, what is the average value of the current ?

Answer 1

As explained in , ampere-hour meters are calibrated to read directly in mWh at the declared voltage. 

Obviously, their readings would be incorrect when used on any other voltage. 

Reading on 210 volt = 730 kWh 

Reading on 230 volt = 730 × 230/210 = 800 kWh (approx.) 

Average current = 800,000/230 × 200 = 17.4 A