Where is the best location to install a magnetic contact on a perimeter door?

• A. Top leading edge of the door
• B. Bottom edge of the door
• C. Center of the door
• D. On the door handle

Answer: (A)

The best location is the top leading edge of the door because this area stays more stable and aligns most reliably with the corresponding switch on the door frame as the door opens and closes. Mounting the magnet on the door and the reed switch on the frame near the top minimizes the risk of misalignment from door sag, weather stripping, or settling, and it keeps the sensing pair out of harm from foot traffic, thresholds, or door hardware. Placing the contact at the bottom, center, or on the handle is more prone to misalignment, interference, or tampering, leading to false alarms or detection failure.