Multiconductor non-power-limited fire alarm circuit cables shall not be installed ______________ in ducts.

The installation guidelines for multiconductor non-power-limited fire alarm circuit cables are designed to ensure safety and reliability in fire alarm systems. In this context, the term "exposed" refers to cables that are not protected by a conduit or other shielding, making them vulnerable to physical damage or environmental interference.

When cables are installed in an exposed manner, they can be more easily subject to abrasion, impact, and other hazards that could potentially compromise their integrity or functionality. This is particularly critical in fire alarm systems where reliability is essential for early detection and response to fire events.

The regulations typically require that non-power-limited fire alarm circuit cables must be installed in a manner that provides adequate protection, which is not the case when referring to exposed installations. Therefore, by prohibiting the installation of these cables in an exposed manner, safety standards help ensure that fire alarm systems function correctly when needed, minimizing the risk of failure during crucial moments.