Can we talk about how I wired motion detectors backwards for 2 years?

I had a call back at a house in Salem last Tuesday where the alarm kept false alarming at night, and the homeowner showed me the LED was flashing during a test - turns out I had the NC and COM reversed on every single one of my installs. Anyone else ever mix up basic terminal connections and feel like an idiot when it finally clicks?

3 comments

3 Comments

anthony1291mo agoMost Upvoted

Oh, you mean like the time I spent six months troubleshooting a thermostat that was wired backwards by yours truly? @jasonf17 let me tell you, that flashing LED might as well have been a spotlight on my entire career. I had the RC and RH reversed on a heat pump system, and the poor customer kept calling me back saying the aux heat ran nonstop. It took a neighbor walking over and pointing it out at a cookout for me to finally see it. The worst part is, I had double-checked my work three times before leaving the job. I still feel that cringe every time I look at a thermostat.

jasonf171mo ago

Two years of backwards wiring and nobody noticed until a flashing LED ratted you out lmao.

nora1101mo ago

I read somewhere that something like 40% of alarm techs mix up NC and COM at least once in their first year, so you're definitely not alone there. That stat made me feel a lot better about the time I spent a whole afternoon chasing a phantom zone 2 fault on my own system before realizing I'd done the same thing. It's one of those mistakes that feels huge in the moment but is actually a super common rookie error that most people just don't talk about.