Door magnetic contact sensor BLOW 4919# HO-03B white — wired door/window sensor

Wired door/window magnetic contact sensor BLOW 4919# HO-03B in white is a compact contact switch designed to detect the opening and closing of doors and windows. The device uses a reed switch (kontaktron) and provides a straightforward normally closed (NC) or normally open (NO) input for connection to alarm control panels, access control units, or other security systems. Its small form factor and surface-mount design allow installation on frames and sashes where reliable state detection is required.

Advantages

The BLOW 4919# HO-03B offers a simple wired interface compatible with many alarm panels and controllers, ensuring predictable behaviour in security installations. Its reed-switch mechanism delivers mechanical reliability with low power consumption and long service life. The sensor’s compact and unobtrusive white enclosure enables discreet mounting on most doors and window frames while maintaining consistent contact alignment between magnet and sensor.

Suitable for

• Perimeter security for residential doors and windows
• Commercial premises where wired inputs are preferred for integration with alarm panels
• Access control systems requiring door state monitoring
• Auxiliary monitoring of cabinets, shutters or gates with compatible mounting

Key specifications

• Type: Wired magnetic reed contact sensor
• Contact configuration: Supports normally closed (NC) and normally open (NO) wiring
• Mounting: Surface-mount on door/window frame and sash
• Housing colour: White
• Detection method: Magnetic reed switch (kontaktron)
• Application: Designed for integration with alarm and security control panels

How to use

Mount the sensor body on the door or window frame and align the magnet on the moving sash so the two parts are flush when closed. Connect the sensor wires to the alarm or control panel input according to the required normally closed or normally open configuration, following the panel manufacturer’s wiring diagram. Ensure cable routing avoids sharp bends and protects against mechanical damage; secure wiring with clips or conduit where appropriate. After installation, test opening and closing to verify reliable state changes are reported to the control system.

Usage recommendations

Install the sensor where the magnet and contact maintain consistent alignment; keep the gap within the manufacturer’s recommended distance. Use appropriate insulation and strain relief for exposed wiring and verify compatibility with the control panel’s input type and end-of-line resistor requirements if applicable.