Intersection between two duration

Hi Janey, 

Sorry for my late reply. I tried to use you pbix file, and to be honest it didn't really work as it shoud. 🙂 
I'm sure it's my fault, don't worry. Nethertheless, I succeded by doing something else. Here is the idea if someone needs it : 
- I "un-pivoted" my columns so I have the devices on different columns.

- I used (in PQ) the fill up option, from the top to the bottom. So the if there is a blank (like if a device give its state and not the other), it will take the last state declared. 
- Now I have for each time, 2 declarations for the 2 devices. So it is way easier. Just have to filter my table with State device 1 ="On"&&State device 2="On". 

It may not be the best solution, but for now, it is the best I have. 🙂 

Anyway, many thanks to you Janey, for having helping me !
Greg