D20 Surface Magnetic Door Contact White for Intruder Alarm and Access Control

Magnetic door contacts are the standard detection device for monitoring the open or closed state of doors and windows in intruder alarm systems. The device has two parts: the sensor body (wired to the alarm panel zone circuit) fixed to the static door frame or window frame, and the magnet (no wiring needed) fixed to the moving door or window leaf. When the door is closed, the magnet keeps the sensor in its held state; when the door or window opens, the magnet moves away and the sensor changes state, generating a zone signal to the alarm panel.

Surface mounting is the quickest installation method: the sensor body and magnet are both fixed to the surface of the frame and door with screws, requiring no routing or rebating into the door frame. Surface mounting is appropriate for light commercial, retail, and residential installations, and for any position where the door or window frame does not have a recess for a flush-mount contact.

White finish is the standard colour for interior residential and commercial alarm installations, matching painted door frames and window surrounds.

The D20 is a passive device requiring only the sensor body to be wired into the alarm panel zone circuit. Polarity and EOL (end-of-line) resistor requirements are set by the alarm panel specification and should be confirmed before wiring.

For intruder alarm engineers completing door and window contact installations across London and the UK, the D20 white surface magnetic contact provides the standard alarm zone detection device for doors and windows.

Key Features

• Surface magnetic door contact: sensor body and separate magnet, white finish
• Generates zone signal when door opens and magnet separates from sensor
• Surface mount: screw fix to door frame and door, no rebating required
• Wire sensor body to alarm panel zone circuit (magnet requires no wiring)
• Confirm EOL resistor and polarity requirements for the connected alarm panel
• Standard detection device for doors and windows in intruder alarm zones