How many power sources are mandated for failsafe magnetic door holders?

Failsafe magnetic door holders are designed to ensure that doors remain closed during incidents like a fire, minimizing the spread of smoke and fire. The requirement for power sources in these systems is fundamental for their operation.

A failsafe system relies on a primary power source to keep the magnetic holders energized. In the event of a power failure, the lack of power causes the magnets to release, allowing the door to close automatically. This is critical for safety, as it prevents doors from remaining open when they should be closed to contain smoke and heat.

The correct answer reflects the fact that only one power source is needed to maintain the operational integrity of the failsafe magnetic door holders, ensuring that they perform correctly in emergency situations. Having a single, reliable power source simplifies the design while providing a failsafe operation during a power failure.

Power redundancy is often a consideration in other systems, but in the context of failsafe magnetic door holders, only one power source is mandated, streamlining installation and ensuring compliance with safety standards.