New York State Master Electrician Practice Exam

What must a service disconnecting means do when a power supply failure occurs?

1. Shut down automatically

2. Be manually operable

3. Turn off all connected devices

4. Reset itself

The correct answer is: Be manually operable

The service disconnecting means must be manually operable to ensure that a qualified person can control the power supply to the electrical system when needed. This requirement reflects the fundamental principle of providing safety and control over the electrical power in a building or facility. In the event of a power supply failure, having a manual means to disconnect power allows electricians or personnel to safely manage electrical systems, conduct maintenance, or respond to emergencies effectively. The ability to control the power supply effectively also ensures that any underlying issues can be addressed without undue risk or danger. A disconnect that shuts down automatically or resets itself may not allow for the immediate and controlled response necessary in certain situations, such as those involving potential electrical hazards or faulty equipment. While the idea of shutting down all connected devices may seem beneficial, it could lead to complications or risks if not managed properly with a manual means of control. Therefore, the primary focus on manual operability is crucial for safe and reliable electrical system management.