I’m trying to install a bathroom fan on it’s own switch.
There is a hot cable with a black, white, and green from a previous light fixture in the spot that I want to install a fan. This hot cable is separate from the existing light fixture and switch combination. I understand that is somewhat concerning but that is a project for another day.
I have also ran a 12 AWG Romex cable (Black/White/Copper) to the existing single gang box for a switch for this new bathroom fan.
How do I marry the new bathroom fan, existing hot cable and new romex cable + switch?
What is the usage of the bare copper wire connected to the metal gang box of the existing switch? My house was built in the 1950s and none of the outlets are grounded. Is this a fake ground?
Diagram of my current situation below.