I want to install a 3-way circuit covering a hallway and stairwell. The top of the stairs and hallway would be covered by the motion sensor and the bottom by the mechanical switch. What happens if I turn on the mechanical switch and never trigger the motion sensor? Does the sensor turn the circuit off after a certain time without motion? Or do I need to either trigger the motion sensor on or manually turn off the mechanical switch?
Just to be clear, I understand how a 3-way switch works and how the motion sensor works. It's just the mixing of the motion sensor and mechanical switch that confuses me.