Hi Paul_KD7HB,
Thank you for the explanation of the color code.
My understanding now is that
Hot -> relay,
Neutral -> wall outlet,
I am still not so sure about the ground, can I connect it with the ground of arduino? Or should I leave it hanging? Or can I connect it to the wall too? My feeling is that it can be connected to the wall for safety. Is this correct?
Thank you!
Best,