Smoke Detector - False Positives, Nuisance Alarms
June 12, 2017 2:21 PM   Subscribe

Wondering if anyone else has heard that arc-fault circuit breaker + wired smoke alarms = more false alarms?

I was awakened AGAIN at 3AM by a false alarm from my wired series of First Alert smoke detectors. I wanted answers. The old kind (not wired together, not wired to house power, just used a 9V battery) NEVER gave false positives. I have had many brands of those type since the 1980s, in multiple dwellings. They went off legitimately when things burned in the kitchen, because they were detecting... smoke. They did not go off for apparently no reason in the middle of the night.

So, I read this:

and this:

But no info I could use yet.

And then my wife texted me from a job site where she was talking to a contractor. He says arc-fault circuit breakers cause wired smoke detectors to give false positives, and his electricians always take those breakers out after inspection (at least on the circuit that is dedicated to the smokes). Sure enough, when I remodeled my home two years ago, the inspector had me put arc-faults on ALL new circuits (surely not a bad idea at all), including the smokes.

Though I am strongly considering just replacing the wired units with a handful of the good old-school 9V independent types (I am hyper-vigilant and have never forgotten to change an old-school smoke detector battery nor ever missed the subtle chirping noise if its battery ran low), I am also just considering replacing that one arc-fault breaker with an old "normal" type breaker in the panel.

So, to reiterate: this question != discuss detector brands, != tell me get CO detector (have one), != how replace circuit breaker (I have that covered). This question = has anyone heard arc-fault circuit breaker + wired smokes = encourages more false alarms.

I hope this turns out to be common knowledge among contractors and electricians who might chime in. If it is true it MIGHT encourage me to swap breaker and keep the marginally safer hard-wired-battery-backup smokes. Otherwise I'm going to party like it's 1989, and no one can stop me!
posted by kiblinger to Home & Garden (1 answer total) 1 user marked this as a favorite
Yes, I have heard of this. Indeed, I recently had a bunch of false alarms caused when I tried to plug my air conditioner into an extension cord. (Don't do that, by the way!) There was no immediate sign that the AC was the problem, but as soon as I unplugged it from the extension cord, the fire alarms stopped tripping. I did a lot of running back and forth to see what happened to the breaker under various permutations of AC-plugged-into-outlet, AC-plugged-into-extension-cord, and so on. It turned out that the arc fault detector was triggering when I plugged the AC into the extension cord only, which in turn caused the smoke detectors on that circuit to go off. Subsequent googling reaffirmed this conclusion.

Long story short: yes, this is definitely a thing.
posted by voltairemodern at 2:34 PM on June 12, 2017 [1 favorite]

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