According to UL guidelines, a motion detector should activate after at most how many steps?

According to UL guidelines, a motion detector should activate after at most how many steps?

• A. Two steps
• B. Four steps
• C. Six steps
• D. Eight steps

Answer: (B)

UL guidelines aim for quick, reliable detection of movement while avoiding frequent false alarms. In a typical indoor layout, a motion detector should trigger after movement that cover roughly the first four steps into the protected area. This keeps the system responsive so a burglar isn’t able to progress far before the alarm sounds, while still preventing nuisance alarms from minor, everyday motions that don’t represent a real intrusion. If the trigger depended on more steps, there’d be a larger window for the intruder to move unseen; if it depended on fewer steps, normal activity could cause false alarms. So, activating after four steps reflects the balance UL seeks between prompt detection and practical reliability.

UL guidelines aim for quick, reliable detection of movement while avoiding frequent false alarms. In a typical indoor layout, a motion detector should trigger after movement that cover roughly the first four steps into the protected area. This keeps the system responsive so a burglar isn’t able to progress far before the alarm sounds, while still preventing nuisance alarms from minor, everyday motions that don’t represent a real intrusion. If the trigger depended on more steps, there’d be a larger window for the intruder to move unseen; if it depended on fewer steps, normal activity could cause false alarms. So, activating after four steps reflects the balance UL seeks between prompt detection and practical reliability.