Magnetic door contact sensor BLOW 4917# HO-03 white

Wired magnetic door contact sensor BLOW 4917# HO-03 in white is a compact reed-switch sensor designed to detect opening and closing of doors and windows. The device consists of a main contact housing and a separate magnet; when the magnet moves away from the contact the internal reed switch changes state and provides a dry contact signal suitable for connection to alarm panels, access control inputs or home automation controllers. Surface-mount installation and a low-profile white enclosure make the sensor unobtrusive on frames and sashes in both residential and commercial environments.

Advantages

The sensor provides a reliable dry contact output compatible with a wide range of wired alarm and automation systems. Its compact, surface-mount design allows installation on narrow frames and in limited spaces while maintaining a discreet appearance in white finish. The use of a separate magnet and reed contact ensures simple mechanical operation with no internal power supply required, reducing maintenance needs. The device is suitable for straightforward wiring and integration into existing security or automation setups.

Suitable for

• Door and window intrusion detection in homes and apartments
• Perimeter monitoring for offices and commercial premises
• Integration with wired alarm panels and access control systems
• Basic presence or state sensing for home automation projects

Key specifications

• Operating principle: reed switch with separate magnet
• Output type: dry contact (normally closed / normally open depending on wiring)
• Mounting: surface mount on door/window frame and sash
• Housing color: white
• Application environment: indoor use (doors, windows, cabinets)
• Connection: wired terminals for low-voltage alarm/automation inputs

How to use

Position the main contact housing on the fixed frame and align the magnet on the moving sash so that the two parts meet within the manufacturer’s recommended gap when the door or window is closed. Run low-voltage wiring from the sensor terminals to the alarm panel or automation controller and configure the input as a dry contact sensor. Verify correct operation by opening and closing the door or window and confirming the panel or controller registers the state changes. Follow standard electrical safety practices and disconnect power to the control system before making wiring connections.

Usage recommendations

For reliable operation, mount the sensor on clean, flat surfaces and avoid locations where the magnet and contact can be subject to repeated impact. Use appropriate cable routing and strain relief to protect connections from wear. Test the contact state after installation and during periodic maintenance to ensure consistent detection and compatibility with your alarm or automation system.