Master Electrician Practice Exam

Battery back-up exit lighting shall receive power from which of the following?

1. Separate dedicated circuit

2. The same branch circuit serving the normal lighting in the area

3. Any branch circuit available

4. Main service panel only

The correct answer is: The same branch circuit serving the normal lighting in the area

The correct answer is that battery back-up exit lighting typically receives power from the same branch circuit serving the normal lighting in the area. This approach ensures that in the event of a power outage, the exit lighting can still function and provide illumination necessary for safe evacuation. It aligns with the goal of having the battery back-up lighting readily available and operational without requiring a separate or dedicated circuit that may complicate installation and maintenance. Using the same circuit allows for efficient use of wiring, reduces installation costs, and minimizes the number of circuits needed in a given area. It ensures that when the main lighting is operational, the exit lighting also receives power, which may include charging the battery system. This can be particularly important in maintaining compliance with safety codes that require exit signs and emergency lighting to be illuminated during power interruptions. The incorrect choices revolve around the necessity of separate circuits or limitations on where power can be sourced. A separate dedicated circuit could be an option for some installations, but it is not a requirement for all scenarios; it may lead to increased complexity without providing an added benefit in typical environments. Similarly, using any branch circuit or only the main service panel would not guarantee that the exit lights function as intended during a power failure, thus not meeting safety and regulatory standards