Question

A fuse in electric circuit is rated 4 A. Can it be used with an electric heater of rating 2 kW, 200 V? Explain your answer.

Answer 1

No, a 4 A fuse cannot be used with this heater.

Current drawn by the heater is:

I = `P/V`

= `2000/200`

= 10 A

Since the heater requires 10 A, which is greater than 4 A, the fuse will blow immediately. Therefore, a fuse of rating more than 10 A (e.g., 15 A) should be used.