What is the minimum number of risers required for a stairway to necessitate a wall switch on each floor for lighting control?

The minimum number of risers required for a stairway to necessitate a wall switch on each floor for lighting control is six. According to the National Electrical Code (NEC), when a stairway has four or more risers, it must be adequately illuminated. However, when there are six or more risers, the code mandates that there should be a lighting control switch at each floor that provides access to those stairways.

This requirement ensures that occupants have the ability to turn on or off the lighting for safety and convenience while using the stairs, especially in areas where visibility is crucial to prevent accidents. By having a switch on each floor, it enhances the practicality of the lighting system, enabling users to activate the lights before ascending or descending, thus reducing the risk of slipping or falling in poorly lit areas.

The other options fall short by not aligning with the specific requirements dictated by the code based on the number of risers, which is important for ensuring compliance with safety standards.