Ground loop hum drove me nuts for a year, then I eyeballed the panel

Kept chasing intermittent buzzing on a residential install in Austin, swapped sensors, re-ran zones, even replaced the keypad. Turns out the transformer was sharing a junction box with a landscape lighting driver, and every time those lights kicked on at dusk the hum came back. One 15 minute fix separating the grounds and it's been dead quiet for 5 weeks. Anyone else ever traced a weird noise to something totally outside the alarm circuit?

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viola_ward7d ago

My buddy had a similar headache with his garage door opener interfering with his office phone system. We finally found the culprit was a cheap power strip plugged into the same outlet as both devices, and the phone static only happened when the motor was running. Moving the strip to another circuit cleared it up in five minutes, no new parts needed.