1.
Estimate the current carrying capability of a conducting wire from the main distribution board to the meter. The main distribution board has three light/fan circuits of 800 W each and two 15 A power circuits of 1.5 kW each. The safety factor and power factor are 1.5 and 0.8 respectively.
A
50 A
B
30 A
C
65 A
D
45 A
View Answer
Correct Answer: D — 45 A
Explanation:
The correct answer is D: 45 A.
Lighting/fan load: 3 × 800 = 2400 W
Power load: 2 × 1500 = 3000 W
Total load: 2400 + 3000 = 5400 W
Applying power factor: S = 5400 / 0.8 = 6750 VA
Applying safety factor: S = 6750 × 1.5 = 10125 VA
Current: I = 10125 / 230 = 45 A