Help! I’m trying to add a the monoprice dual relay module to two light switches in my house. Of course, my house was built in 1926, which means nothing here is ever easy.
Here’s my problem: I opened up the outlets, and the wiring doesn’t make much sense to me.
Outlet one (far right, first photo below) has three wires - a red and black at the bottom, and white at the top.This is a 3-way switch - there’s another switch that controls these lights. From what I’ve read, these relay modules can be installed on some 3-way switches, so I wanted to try it here.
Outlet two (middle of three outlets in photos, second photo below) only has two wires: A black and a white. And the white is coming from outlet 1, not the wall, which really confuses me.
Right now, here’s my best guess: Black wire is live, white wire the load (and these two switches share a load - not sure if that’s actually possible), and red wire goes to the other switch for the 3-way. And these are just old enough that there is no ground.
Does this make sense? Any other explanations? Is it possible to use the monoprice relay without a ground, or am I screwed?