Final answer:
To control stairway lighting, wall switches are required at each level when the number of risers that separate floor levels is more than one.
Step-by-step explanation:
To control stairway lighting, wall switches are required at each level when the number of risers that separate floor levels is more than one.
This means that if there are more than one risers between floor levels, there should be a wall switch at each level to control the stairway lighting.
For example, if there are 10 risers separating floor levels, then there should be a wall switch at each of the 10 levels to control the stairway lighting.