Can I disconnect and "abandon in place" hardwired smoke detectors?

September 27, 2020 2:41 PM

I replaced a bunch of old hardwired "dumb" smoke detectors (like, 6 of them) with a gaggle of battery-powered Nest alarms. When I unclipped the dumb ones from the power supply, I just nudged the plastic connector/wires into the wall hole and screwed back on the now-unpowered detector. So the detector is still on the wall but the plug is disconnected behind it. Is it a terrible idea to have the powered clip in the wall behind the unplugged detector, or is it okay if it's not connected to anything? If I need to properly decommission them, do I just pay an electrician to cap them off?
posted by AgentRocket to Home & Garden (7 answers total)

I've done this to a couple of mine. The only problem I can see is if you move and someone else moves in thinking the detectors are active. So if you ever move I would either plug them all back in or put some sort of sticker on them that clearly states that they are inactive.

Most likely all your detectors are on the same breaker so you might just want to turn it all off at the panel.

Also all those detectors probably have batteries in them as well so you'll want to remove the batteries so they don't all start chirping when they run low.

I wouldn't be surprised if they sold blanks so that you could just remove them and cap them off yourself.

Please note that, like all electrical and/or safety advice, this advice is from "some guy on the internet" and could actually be terrible. Your local fire inspector might have a completely different idea of what is safe or legal.
posted by bondcliff at 2:53 PM on September 27, 2020

I don't think it's illegal to just leave them there, assuming you aren't using your home for childcare or some other regulated activity (where, although I'm sure it varies by state/locality, you might get into issues if you leave them up but inoperative). But I would properly decommission and dispose of them.

You probably don't need an electrician to cap them off, if you've already pushed the wires up into the junction box, you can remove the plastic mounting ring that held the old one on, and simply screw a round blanking plate onto the junction box to conceal everything. It's no harder than installing a new smoke detector, really, at least IMO.
posted by Kadin2048 at 2:53 PM on September 27, 2020 [1 favorite]

This probably doesn't help you now, but if you are within the return window, Nest has a version of the Protect that will allow you to connect to the AC power. They take batteries also, but get their main power from the wall wiring.

As far as an answer to your direct question, if I were doing this in my house, I'd disconnect the old connectors. There are probably only two wires (black/hot and white/neutral) and the alarm connector is probably connected to the house wiring with a wire nut on each. Remove the wire nuts one at a time, and screw them back on to the house wires.
posted by tomierna at 3:13 PM on September 27, 2020

I'd be really cautious about getting rid of the hard wired power. NFPA 101 (Life Safety Code) requires it in rehab or new construction. This requirement was added maybe 20-25 years ago.
Looks like your state also requires it - less some exceptions that would not seem to apply since you already have the hardwire power in place.
posted by rudd135 at 3:43 PM on September 27, 2020 [3 favorites]

Response by poster: Thanks everyone. What I was worried about is that the wires would somehow start a fire in the wall or something (that would be ironic, eh?)

Good point rudd135 - I will review the code to be sure I am okay.
posted by AgentRocket at 3:57 PM on September 27, 2020

If I understand your setup correctly, you just pulled the plug out of the hard-wired detectors, shoved the little plug-in jack back into the box, and installed the battery-powered detectors over the top? I can't imagine that would cause problems. On the other hand, you could check to see if one of your circuit breakers is exclusively for powering your smoke detectors and just shut that breaker off; that's how my house is wired.
posted by Betelgeuse at 5:52 PM on September 27, 2020

I also just replaced network of 3 wired detectors with 3 dumb ones. My wired ones were wired with a plastic plug, which I unplugged and covered with a piece of black tape. There weren't any exposed wires or pins in the plugs, so black-taping was really done from an excess of caution. The new detectors' mounting plates went right onto the junction boxes the old ones' plates came off of. The replacement was trivial. I've kept the old wired ones, just in case - like someday selling the house or needing an inspection by the building inspector or fire department. I don't feel in the least bit bad about doing this. In 30 years of using smoke detectors, the only issues I've *ever* had were the low-battery warnings of one in a a cold attic. And any issue, like a low battery or alarming at burnt toast, can be shut off while the problem gets rectified. Hardwired ones? Wake the whole damn household at 2am because one of the needs to be vacuumed!! You can't shut it off so you can go back to sleep and fix it in the morning, you can't sleep through it, and you can't explain to your dog who's scared-shitless, that the world isn't about to end. Screw 'em. If they hadn't turned out to be trivial to replace, I'd have "adjusted" them with a hammer.
posted by TruncatedTiller at 5:47 PM on September 28, 2020