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A building runs 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and one 1 kW heater on a 220 V supply. What is the minimum current rating required for the building's main fuse?

1. 12 A
2. 14 A
3. 8 A
4. 10 A

Correct answer: 12 A

Solution

Total power = 2500 W, so the line current is 2500/220 = 11.36 A; the smallest standard fuse above this is 12 A.

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