What is one of the main advantages of using plenum-rated cables?

Plenum-rated cables are specifically designed for use in spaces where air circulates for heating, ventilation, and air conditioning (HVAC). One of the primary benefits of these cables is their construction, which features insulation materials that are designed to limit the spread of fire and reduce smoke production. This is crucial in plenum spaces—areas within buildings where air is distributed—because if a fire were to occur, the smoke could spread quickly through the HVAC system, endangering occupants and making evacuation difficult.

The fire-resistant properties of plenum-rated cables ensure that they comply with safety standards, allowing them to be safely installed in ceilings or floors where they might be exposed to air circulation. As such, their use is mandated by building codes in many areas, particularly in commercial buildings where safety is paramount.

In contrast, other options refer to cost or suitability for outdoor use, which do not address the core function of plenum-rated cables in fire safety scenarios. Since maintaining safety in the event of a fire is critical, the characteristics of plenum-rated cables that enhance their fire resistance and smoke mitigation capabilities are what set them apart and make option D the most accurate choice.