AC wired smoke detector connections


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Old 04-14-24, 04:06 PM
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AC wired smoke detector connections

I recently replaced an end of life smoke detector. New smoke detector is BRK First Alert model SC7010BVA.

Seemed pretty straightforward until the new smoke detector started randomly beeping at random time intervals. Of course the beeping doesn’t correspond to any of the sequence of beeps in the user manual troubleshooting guide, so I have no clue what the issue is.

My smoke detector box has 3 pairs of wires coming out of it. Two black wires with white paint on them (these wires give a reading with my voltage tester, so they are the HOT wires). Two red wires. And two white wires.

The smoke detector has 3 wires. Black wire is supposed to connect to the hot wire. White wire to neutral. And orange wire for interconnected detectors (I am not connecting the orange wire to anything which is okay as per instructions).

The smoke detector instructions say that when the smoke detector’s green light is illuminated it is receiving AC power. I connect the black smoke detector wire to the hot wires in the box and when I connect the white wire to the white wires in the box the green light illuminates, indicating AC power. However, when I connect the white wire to the red wires in the box as I did when troubleshooting, the green light also illuminates indicating the smoke detector is receiving AC power.

My question is, which wires should be connected here? Not sure if I have a defective smoke detector here. Thanks

 

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04-15-24, 06:12 AM
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Without a neutral connection the detector would not work.

The smokes need to be compatible with each other. Please test to ensure working units for your safety.
 
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Old 04-14-24, 04:20 PM
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Did you try changing the batteries?

You should not be connecting things willy nilly to the red wire, since you could damage the other smoke detectors, and anyway, it serves no purpose.

Generally one replaces all the smoke detectors at the same time, which guarantees compatibility of the communication link (orange/red wires).


 

Last edited by Luke M; 04-14-24 at 04:31 PM.
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Old 04-14-24, 04:27 PM
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Combination 120v/battery detectors should be changed every ten years.
They should be replaced all at the same time.
White and black are 120vac power.
The red is the interconnect wire that ties the units audibles together.

Don't connect anything randomly to the red wire.
If you change units at different times.... the interconnect method may not be compatible and will cause random audible noises between units.
 
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Old 04-14-24, 06:55 PM
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Yes to what the other posts said plus bottom line is all reds go together, all whites go together, and all blacks go together.

Now as for BRK ...personally I would not buy this brand. I had problems with them....I connected 6 and was 100% accurate on the wiring. But they beeped intermittently like yours. I took them all out, replaced them with Kidde and all is well--no problem.
 
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Old 04-15-24, 12:07 AM
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Yes, unfortunately when it is time to replace one interconnected smoke detector it is time to replace all of them and all of them should be the same brand and model to help increase the overall compatibility of all of the detectors.

Wiring of hardwired smoke detectors is usually straight forward; black to black, white to white and red to red (red/orange are the signal wires, which communicates detector to detector).
 
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Old 04-15-24, 05:05 AM
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Thank you for the help everyone. What threw me off was the original smoke detector had its black wire connected to the hot (black) wire in the box and its white wire was connected to the red wire in the box. Now I'm not even sure if that detector was working at all.
I've reconnected the new smoke detector (black wire to black hot wire, white wire to white wire in the box and orange wire tucked in the box not connected) and it seems okay now. I did take out the batteries and test them as well. I thought replacing a smoke detector would be a straightforward operation. Anyways, next time I'll be replacing all at the same time. Unfortunately my other two detectors were replaced two years ago and those models have been discontinued.
 
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Old 04-15-24, 06:12 AM
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Without a neutral connection the detector would not work.

The smokes need to be compatible with each other. Please test to ensure working units for your safety.
 
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Old 04-25-24, 10:30 AM
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The smokes need to be compatible with each other. Please test to ensure working units for your safety.
I'll reiterate what pcboss mentioned because I think it's important.

It's code required that your detectors all communicate and sound together. Plus, it's really important.

My family had a close-call when I was a kid. A fire started in the basement one night, and because we kept the basement door closed, the fire was raging by the time enough smoke made it to the first floor detector. A few extra minutes and we probably wouldn't have made it out of the house. Though there was a battery detector in the basement, it didn't help because no one heard it. If it were interconnected, we would have heard it much earlier and it would have been significantly less damage (and other bad potential outcomes).

IMO, investing $100-200 is well worthwhile every 10 years to replace the detectors. Make sure at least one is a CO detector (if you have gas/wood burning appliances) and a new fire extingusher.

Ok, off my soapbox
 
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Old 04-26-24, 01:41 AM
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From the NFPA:
  • Smoke alarms with non-replaceable 10-year batteries are designed to remain effective for up to 10 years. If the alarm chirps, warning that the battery is low, replace the entire smoke alarm right away.
  • Smoke alarms with any other type of battery need a new battery at least once a year. If that alarm chirps, warning the battery is low, replace the battery right away.

https://www.nfpa.org/education-and-r...Interconnected
 
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