What is the main characteristic of the cables designated for plenum spaces?

Cables designated for plenum spaces are specifically designed to have a minimal emission of smoke and fumes when subjected to fire. This characteristic is critical because plenum spaces are often used for air circulation in buildings, and if a fire were to occur, reducing the quantity and toxicity of smoke and fumes is essential to maintain air quality and enhance safety during evacuations and firefighting efforts. The cables are typically constructed using special materials that comply with building codes and fire safety regulations, making them suitable for use in these high-risk areas.

While low cost, waterproof coating, and heavy duty construction might be beneficial for other applications or environments, they do not specifically address the unique requirements for plenum spaces, where fire safety and the emission of harmful substances are paramount concerns.