As per IE Rules, the terminal voltage must be within the ________ range, if the nominal voltage is 240 V.

India Electricity Rule No. - 54

A supplier shall not permit the voltage at the point of commencement of supply to vary from the declared voltage.

a) In case of low & medium voltage, the variation not more than by 6%.

b) In case of High voltage by 6% in the higher side and 9% in lower side.

c) In case of extra high voltage by 10% in the higher side and 12.5% in lower side.

Calculation:

± 6 % of 240 V

\( ± \;\frac{6}{{100}} \times 240 = \; ± \;14.4\;V\)

Required voltage = 240 ± 14.4 V 

Required voltage = 225.6 & 254.4 V

Therefore voltage should not drop below 225.6 V and should not exceed by 254.4 V.

So the correct range will be 228 V to 252 V.

Important Points

India Electricity Rule No. - 55

Variation in frequency of A.C supply should not be more than 3%.