Interior stairway lighting outlets in dwellings shall be controlled by a wall switch at each floor level where the difference between levels is ___ steps or more.

Interior stairway lighting outlets in dwellings shall be controlled by a wall switch at each floor level where the difference between levels is ___ steps or more.

• A. 3
• B. 12
• C. 6
• D. 11

Answer: (C)

The main idea is safety: you want to be able to light the stairs before you start climbing, so falls are less likely. Interior stairway lighting outlets in dwellings must be controlled by a wall switch at each floor level when the vertical difference between levels is six steps or more. Six steps gives a noticeable flight length where turning on the light from the entry door is important to avoid stepping into darkness. Six steps is used because a typical stair rise is around 7 inches, so six risers represent a meaningful climb. Requiring a switch at each level ensures you can illuminate the steps from the door opening at every level that connects to stairs, reducing the chance of navigating a dark stair that could lead to a misstep. If the levels are fewer than six steps apart, this extra-level switch requirement doesn’t apply, and standard lighting control can be used.

The main idea is safety: you want to be able to light the stairs before you start climbing, so falls are less likely. Interior stairway lighting outlets in dwellings must be controlled by a wall switch at each floor level when the vertical difference between levels is six steps or more. Six steps gives a noticeable flight length where turning on the light from the entry door is important to avoid stepping into darkness.

Six steps is used because a typical stair rise is around 7 inches, so six risers represent a meaningful climb. Requiring a switch at each level ensures you can illuminate the steps from the door opening at every level that connects to stairs, reducing the chance of navigating a dark stair that could lead to a misstep. If the levels are fewer than six steps apart, this extra-level switch requirement doesn’t apply, and standard lighting control can be used.