I am upgrading a lot of light switches in my home to Z-Wave smart switches. It is easy when it is a simple switch, but a 3-way, 4-way or n-way switch circuit is trickier. When doing so, I need to know where the hot "line" wire is and where the most downstream "load" wire is.
I am able to accomplish this but it is time consuming. My current approach is as follows:
- Shut power off at the breaker for the circuit
- Pick a switch and disconnect it
- Turn power back on at the breaker
- Probe the wires at the disconnected switch. If I find a hot wire, then go flip a switch elsewhere in the circuit and probe again. If the hot wire remains hot, I have found the most upstream "line" wire. If not, I know the most upstream "line" wire isn't at this switch. [REPEAT FROM STEP 1 with a new switch]
- Once the "line" wire is identified, I can then use a similar technique to identify the wire that powers the lights.
This takes a really long time, especially when other people (and children) are in the house and you have to ensure nobody else is in danger of touching an exposed wire.
I can reliably and consistently identify the line & load wires using this method, but I am really hoping someone has a hack or shortcut to quickly accomplish this same goal.