Replacing a very old 3way switch
I’m attempting to replace a very old 3way seitch.
It has four terminals: top two are black and white, and the bottom only has one black connection. I suspect the upper black wire is power because it is shared by a jumper to the top of a light switch that only connects to a bulb. What are the roles of the other wires?
I’m attempting to connect to a Honeywell RPLS540A/RPLS541A dusk dawn timer. This requires 4 wires:
Yellow for 3way switch
Green for ground
Black for load
Black for line
What wires from the existing switch should I wire into my new device?
Additionally, I see a copper wire at the back of the box wrapped around a screw. The box itself is metal. Is this my ground wire?
in progress 0Electrical 3 years 1 Answer 527 views 0