The stairway difference requirement for wall switch control is six steps or more. Which option reflects this requirement correctly?

The stairway difference requirement for wall switch control is six steps or more. Which option reflects this requirement correctly?

• A. The difference must be at least 3 steps
• B. The difference must be at least 6 steps
• C. The difference must be at least 11 steps
• D. The difference must be at least 12 steps

Answer: (B)

Having wall switches at both ends of a stairway improves safety by letting you illuminate the stairs from the top or bottom before you start. The standard sets a threshold: when the stairway between floors has six steps or more, wall switch control must be provided at both ends. That makes the option stating at least six steps the correct one. A smaller difference, like three steps, wouldn’t guarantee you can reach a switch before stepping onto the stairs, so it doesn’t meet the requirement. Much larger numbers (like eleven or twelve) aren’t the defined threshold for this rule, though longer stairs often do have two switches. In practice, you’ll typically see a switch at the top and bottom of longer stairways to ensure lighting is available from either end.

Having wall switches at both ends of a stairway improves safety by letting you illuminate the stairs from the top or bottom before you start. The standard sets a threshold: when the stairway between floors has six steps or more, wall switch control must be provided at both ends. That makes the option stating at least six steps the correct one. A smaller difference, like three steps, wouldn’t guarantee you can reach a switch before stepping onto the stairs, so it doesn’t meet the requirement. Much larger numbers (like eleven or twelve) aren’t the defined threshold for this rule, though longer stairs often do have two switches. In practice, you’ll typically see a switch at the top and bottom of longer stairways to ensure lighting is available from either end.