Question

An electric iron draws 10 amp, an electric toaster draws 5 amp and an electric refrigerator draws 3 amp from 220 volts service line. The three appliances are connected in parallel. If all the three are operating at the same time, the fuse to be used should be of

Answer 1

hope this helps you.

Answer 2

Answer: The fuse used is $174.13 \Omega$

Given are the three electrical appliances with drawing current as,

E (iron) = 10 A and E (toaster) = 4 A and also, E (refrigerator) = 3 A.

And all are connected in parallel, therefore the total current flowing in the circuit at the same time of their functioning will be given by,

              $I_{ total }=V(\frac { 1 }{ 10 } +\frac { 1 }{ 5 } +\frac { 1 }{ 3 } )$

      $\Rightarrow I_{ total }=220(\frac { 15+30+50 }{ 150 } )$

      $\Rightarrow I_{ total }=139.3$

And the Fuse rating is calculated by Current times 1.25, therefore,

              Fuse rating = $I_{total} \times 1.25$

         $\Rightarrow Fuse\quad rating = 139.3 \times 1.25 = 174.13 \Omega$