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Stop running alarm wire right next to electrical lines
I keep seeing guys zip tie my alarm cables right against 120v romex in basements. Did a service call last month at a house in Denver where the interference was so bad the motion sensors were going off every time the fridge kicked on. We had to rerun 200 feet of wire because someone was lazy about separation. How do you all handle runs when the sparky already finished and left no room?
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rosebarnes1d ago
Man, I once saw a guy run alarm wire through the same conduit as a furnace line and the whole system just hummed constantly
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sethhernandez1d ago
@rosebarnes I think you might mean it was a thermostat wire or a low voltage control wire instead of an alarm wire. Alarm wire is usually 22 gauge and has more conductors, but the problem is the same either way. Running any low voltage signal wire in the same conduit as power cables can cause tons of interference issues. The electromagnetic field from the furnace line induces voltage into the alarm wire. That creates that humming sound you heard because the signal gets all mixed up with the power frequency. You really should keep those separated by at least a few inches if not in different conduits altogether.
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sandraflores1d ago
Hate to push back but maybe that hum was from something else entirely. I've run signal wire next to heavy power lines plenty of times without any noise issues if the shielding is good and the grounds are proper. Blaming the conduit just sounds like an excuse for bad wiring or a cheap system.
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