Question 390Electricity & Electronics - Assistant Engineer

The correct answer is D) 3 fixtures. According to 46 CFR 111.75-5, the maximum allowable additional lighting fixtures that can be installed on circuit No. 1 is 3. This is because the regulation states that the total connected load on a lighting branch circuit must not exceed 80% of the circuit's rating. With each fixture being 100 watts, and the circuit being 120 VAC, the total additional load from 3 fixtures would be 300 watts, which is within the 80% limit of the circuit's capacity. The other options are incorrect because 1 fixture (B) would be too low, and 2 fixtures (C) would exceed the 80% limit of the circuit's rating.