Question

Three appliances are connected in parallel to the same source which provides a voltage of 220 V. A fuse connected to the source will blow if the current from the source exceeds 10 A. If the three appliances are rated at 60 W, 500 W and 1200 W at 220 V, will the fuse blow?

Answer 1

Given: P₁ = 60 W

P₂ = 500 W

P₃ = 1200 W

Voltage (V) = 220 V

P_total = P₁ + P₂ + P₃

P_total = 60 + 500 + 1200

P_total = 1760 W

We know that,

P = VI

I_total = `P_"total"/V`

⇒ I_total = `1760/220`

⇒ I_total = 8 A

The fuse will not blow because the total current of 8 A drawn by the three appliances stays safely below the 10 A rating of the fuse.