A friend of mine asked me to look at a timer switch he attempted to install. The box looks like it is at the end of the run, coming from an outdoor light. there are no wires leaving the box. The problem is that the wire coming in is 4 wire, red, black, white and ground. 3-way wiring?? But my friend swears the outdoor light is only controlled by one switch. 120v indicated with Multi meter across red and black and red and white and 0v across the black and white.
1. General question. How is a timer switch wired at the end of the run? Timer wiring diagram in middle of the run is supplied with the timer. easy enough. How is it done at end of run?
2. Could this 4 wire only be using 3 of the wires?