What is the special conduit for electrical wiring that runs vertically from one floor to another in a building?

The correct answer is the electrical riser, which is specifically designed to accommodate vertical runs of electrical wiring between different floors in a building. An electrical riser typically contains insulated conductors that help distribute electricity safely and efficiently throughout the structure. This conduit helps organize and protect the wires as they connect various systems across different levels while also allowing for easier access during installation and maintenance.

Other options, such as busway or raceway, refer to distinct systems for electrical distribution or protection but are not specifically optimized for vertical travel between floors. A busway is a system that utilizes a prefabricated metal busbar assembly to carry large amounts of electrical current, often used for horizontal runs. A raceway is a general term that refers to pathways designed to hold wires and is not limited to vertical transmission. Lastly, a cable tray is meant for supporting insulated electrical cables used for power distribution and may be used horizontally or vertically, but is not as specialized for vertical runs within a building as a riser.