Certified Fiber Optics Practice Exam

What is the designation for a cable that runs vertically between floors?

1. Riser

2. Plenum

3. Branch

4. Drop

The correct answer is: Riser

The designation for a cable that runs vertically between floors is known as a riser cable. This type of cable is specifically designed to handle vertical runs in a building, such as between different floors or levels. Riser cables must be constructed from materials that are fire-resistant to prevent the spread of flames along the cable path in the event of a fire, as they often utilize vertical shafts that can act as chimneys, facilitating fire and smoke movement through the building. In contrast, plenum cables are used in spaces where air circulation for heating and cooling is provided (like air ducts), branch cables refer to those that distribute from a main line to multiple endpoints, and drop cables are the final segment of cable that connects from a distribution point to an individual user or device. Understanding these distinctions is important for proper installation and compliance with safety regulations in building cabling infrastructure.