Raceways and cables installed into the ______ of open bottom equipment shall not be required to be mechanically secured to the equipment.

The correct answer is the term that refers to the area of open bottom equipment where raceways and cables can be installed without the necessity for mechanical securing. In many installations, especially those with open-bottom equipment, raceways and cables can be positioned such that they are supported by the equipment itself. This eliminates the need for mechanical securing, which can be a requirement in other situations.

Open bottom equipment typically allows cables or raceways to rest on or be routed through designated channels or supports that are designed to hold them in place without additional fasteners. Therefore, the area referred to as the "bottom" of the equipment is suitable for such an installation because it inherently provides support, allowing the cables and raceways to remain stable without mechanical devices.

Understanding this helps in recognizing design and safety considerations while wiring, as some environments may have different requirements for securing cables and raceways based on their location and the nature of the equipment.