Serious question, why do so many people run their sensor wires right next to the power lines?

I was fixing a system in a Portland house last month. The owner said it kept giving false alarms. Found the sensor wire for the back door ran right next to the main power feed for the kitchen. About two feet of parallel run. That's just asking for noise. Moved the low voltage wire just six inches away and the problem stopped. It's a basic rule but I see it all the time in old installs. How do you guys handle rerouting wires in a finished house without tearing up walls?

3 comments

3 Comments

the_michael2mo ago

You mentioned old installs working fine for years. That's the thing, it's a ticking clock. I had a system that was perfect for a decade until the homeowner got a new fridge. The compressor kicked on and suddenly we had a parade of zone faults. The noise was always there, but the new appliance pushed it over the edge. It took me a full day to trace and reroute that one wire behind the cabinets.

phoenixgonzalez2mo ago

That Portland job is a perfect example. I've fixed three systems this year where moving the wire a few inches stopped the false alarms for good. It's a real issue, not just a maybe.

dylanbarnes2mo ago

Honestly, how much noise are we really talking about here? Most basic alarm panels have some filtering for that. Seen plenty of janky old installs that work fine for years despite bad runs. Sometimes a false alarm is just a bad sensor or a loose terminal block. Not saying it's good practice, but tearing up walls over a maybe seems extreme.

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