Question

An electric kettle rated as 1200 W at 220 V and a toaster rated at 1000 W at 220 V are both connected in parallel to a source of 220 V. If the fuse connected to the source blows when the current exceeds 9.0 A, can both appliances be used at the same time? Illustrate your answer with calculations.

Answer 1

Voltage of the power supply, V = 220 V
Power rating of the kettle, P_k = 1200 W
Maximum current drawn by the kettle, i_k = P_k/V = 1200/220 = 5.5 A
Power rating of the toaster, P_t = 1000 W
Maximum current drawn by the toaster, i_t = P_t/V = 1000/220 = 4.5 A
When both the appliances are switched on together, we get:
Maximum current drawn = i_k + i_t
= 5.5 + 4.5
= 10 A
It is greater than the rating of the fuse; therefore, both the appliances cannot be used at the same time.