At what height must cables be physically protected when being installed within an exposed ceiling?

Cables must be physically protected when installed within an exposed ceiling at a height of 7 feet to prevent accidental damage. This requirement aims to ensure that the cables are safeguarded from impact, particularly in areas where they may be exposed to contact from people or equipment. By mandating a protective measure at this height, the risk of accidental physical harm to the cables—such as nicks, cuts, or complete disconnection—is significantly reduced, which enhances the overall safety and reliability of the fire alarm system.

In many code regulations, including those under the National Electrical Code (NEC) and industry standards, the 7-foot threshold is typically recognized as it allows for adequate clearance in areas with general foot traffic. This height is also practical for maintenance purposes, ensuring that the cables are accessible without needing extensive tools or procedures to work around them. The choice of this specific height reflects an understanding of typical building uses and the need for safety and accessibility in cable management.