HOLT Electricians Practice Exam

How many single-pole breakers can be added to a lighting and appliance branch circuit panelboard with six 3-pole breakers and eight 2-pole breakers?

1. 6

2. 8

3. 10

4. 12

The correct answer is: 8

To determine how many single-pole breakers can be added to the panelboard, we first need to understand how the existing breakers are accounted for in the panel's total capacity. In this scenario, each 3-pole breaker takes up three slots in the panel, while each 2-pole breaker occupies two slots. With six 3-pole breakers installed, they occupy a total of 18 slots (6 x 3 = 18), and the eight 2-pole breakers take up 16 slots (8 x 2 = 16). Adding these together gives us a total of 34 slots used by the existing breakers (18 for the three-pole and 16 for the two-pole). Now, a standard panelboard has a defined number of slots available. Assuming a standard configuration where a typical panel might hold 42 slots (this can vary depending on the specific panelboard model), we can calculate the remaining slots by subtracting the used slots from the total slots. So, if the panelboard has 42 slots and 34 are filled, this leaves us with 8 available slots. Single-pole breakers only occupy one slot each, so with 8 remaining slots, it is possible to