Roller shutter contact - Grade 3

This magnetic contact is suitable for use on roller-shutter doors.  The wedge shaped part is fitted to the bottom of the door and has no wires going to it.  The other half of the detector is the longer part with the cable going to it, you will notice in the picture the cable near that part is already inside armoured protection.  The part with the cable going to it is secured to the floor and when the door is closed the wedge shaped part fitted onto the door lines up with it thus creating the circuit.  If the door is opened when the alarm is set the circuit is broken and generates an alarm condition.  On roller doors wider than 3mtrs we fit two of these contacts, with one on each side.  This is to avoid someone being able to prize up one corner of the roller door and creep underneath it.