Adding A Switch To A Door Sensor
I have a double window or door; do I need to use two Door/Window Sensors?
How can I add an extra magnet switch to a Door/Window Sensor?
It is pretty simple to add another magnet switch to a Door/Window Sensor. The magnet switch has two screw terminals on it. Normally, one magnet switch is wired to the terminals. Whenever the switch opens up or a wire is cut, the sensor sounds the alarm because power is not flowing between the terminals.
To add a switch to a sensor, unscrew one of the two terminals and take the sensor wire out. Get a length of wire; attach it to the free screw terminal, then attach the other end to a screw terminal on the new magnet switch. Connect the free wire from the sensor module to the other screw terminal on the new magnet switch. You now have a loop of wire with two switches in it. If either switch is tripped, the alarm will go off.
You can call 800-675-3044 to purchase extra magnet switches; ask for part number DW-MAG. You can also substitute any normally-closed sensor (NC) made for a wired security system.