Question

A domestic lighting circuit has a fuse of 5 A. If the mains supply is at 230 V, calculate the maximum number of 36 W tube-lights that can be safely used in this circuit.

Answer 1

Let the maximum number of tube-lights be y. 

Power of y tube-lights, P=36y 

V=230V, I=5A 

We know that 

P = VI 36y = 230 x 5 

36y = 1500 

y=31.94

So, number of tube-lights required are 31