Shoutout to the old 3-way switch that taught me to always check the travelers first

I was working on a kitchen rewire in a house built in the 1970s. The homeowner wanted to swap out the old switches for new ones. I figured it was a simple job, so I just turned off the breaker I thought was right and started on a 3-way. I disconnected the old switch, wired up the new one exactly like the old one was, and turned the power back on. Nothing. The light wouldn't turn on from either location. I spent a good 20 minutes checking my connections and the breaker panel before I finally grabbed my meter. Turns out, the two switches were on different circuits. The power feed was at one box, and the switch leg was at the other, with just the travelers running between them. I had only killed power to one side. I learned to never assume both switches in a 3-way are on the same circuit, even in an older house. Now I always verify with a meter before I touch anything. Has anyone else run into this, or is there a faster way to spot this setup before you start?

2 comments

2 Comments

foster.mary7d ago

Heard a similar story about this from an electrician on a podcast last week.

jesse2906d ago

Read a forum post where a guy got zapped because the power feed and switch leg were on opposite sides of a three-way. He said the only safe move is to test every single wire in both boxes with a non-contact tester before you even loosen a screw.