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Model # 21006371

Internet # 100573489

Store SKU # 146389

Hardwired 120-Volt Inter Connectable Smoke Alarm with Battery Backup

This item has been discontinued.
The Home Depot no longer carries this specific product.

$19.97 /each


Model # 21006371

Internet # 100573489

Store SKU # 146389

The Kidde P12040 Hardwire inter connectable Photoelectric Smoke Alarm with Battery Backup can act as a stand-alone unit or can be integrated into an existing electrical system. This unit sounds an early warning to alert you and your family of the presence of visible fire particles detected by the alarm's photoelectric sensor. Powered by 120-Volt AC, this alarm protects you, your home and the people you hold dear even during power outages, thanks to a 9-Volt battery backup. A power harness facilitates an easy installation and a simple push of a button activates this alarm's test and hush features.

  • Utilizes photoelectric sensor to detect visible fire particles
  • Sounds an early warning when smoke or fire particles are detected
  • Offers dual functionality as a single-station alarm or can be interconnected into a wired system
  • 120-Volt AC, 2-wire connection
  • Push-button operation tests alarm functionality
  • 9-Volt battery backup provides protection during power outages
  • 9-Volt battery included (21025730)
  • Pull tab keeps battery fresh until initial activation
  • Power harness makes installation fast and easy
  • Dust cover protects sensor during construction

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Alarm Sensor Type 
Alarm Type 
Alarm/Detector Features 
Battery Back-Up,Hush Feature,Interconnected 
Commercial / Residential 
Commercial / Residential 
Connector/Contact Type 
Power Source 
Voltage (volts) 
Warranty / Certifications
Certifications and Listings 
1-UL Listed 


Rated 3.9 out of 5 by 29 reviewers.
Rated 1.0 out of 5.0 by So disappointed I've owned 2 of these smoke alarms for 2 years. For the past 2 months they have been giving false alarms. They beep 7 times and then stop. In the past 2 months I have changed the batteries twice with the recommended Energizer 522 batteries. No better. I have also taken them down and vacuumed them as well as resetting them. Nothing helps. I have 2 Kidde 10 year battery only alarms in rooms close by and they are not a problem. I can only conclude that it it a bad product. Very disappointed. June 8, 2015
Rated 5.0 out of 5.0 by Fits just right Fits perfect in my trailer. Hard to find items to when things need replaying in a mobile home. The Home Depot had what I needed. And it has a battery back up that the old one did not have. Great Buy. July 30, 2015
Rated 5.0 out of 5.0 by Will replace all my smoke alarms with these. . . Had a problem with one of my networked smoke alarms. . .found these in HD. Swapped out the bad one and problem went away. . .will exchange the remaining in the house soonest. . .great value. . . July 21, 2015
Rated 1.0 out of 5.0 by Short life before repeated false alarms. I have 12 Kidde detectors, four models. I've owned others over 20 years. I had...had..four of this model. All four began giving false alarms, one then the next, between 12-18 mos after install. The irony is that these four were chosen over dual sensor units, not to save money, but because having photoelectric only units near the kitchen and bathrooms is recommended to avoid false alarms in humid environment with "PI" or "I" units. I have had no problems with Kidde dual PI2010's or the four combo photoelectric/co2's that I have. Choose another model. I just threw four of these in the trash. July 1, 2014
Rated 2.0 out of 5.0 by Inconvenient Battery Access I bought 6 of these to replace horrid BRK 4120B models that go off for no reason. Unfortunately, this model has doesn't have side access to the battery. You have to unscrew the alarm, and then ALSO unhook the hard-wire connection before opening the battery case. Yeah, they're easy to install the first time, but if you plan on changing the batteries (which of course you must!) good luck! Guess these are more marketed to contractors, not homeowners who will actually maintain them. March 16, 2013
Rated 5.0 out of 5.0 by Easy to install The smoke alarm was easy to install and a reasonable price. There were several choices to choose from this brand, but chose a medium price. Have one upstairs and downstairs. No problems so far. June 9, 2015
Rated 1.0 out of 5.0 by This is not a good product! I purchased 11 detectors and have them wired with the interconnect feature for a newly built house based on the good reviews. Appr. 3 months - 6 months afterwards these detectors would go off randomly at all hours of the day and night. There is nothing in the instructions that provide any guidance on what may be the cause. I tried to call there customer support line for help and after being on hold for longer then I liked I sent an E-Mail which was never replied too. I decided to change ALL the batteries with brand new well named batteries and it only took 6 weeks for the 1st one to go off (the only good feature with these units is being able to determine which detector is sounding the alarm). As of these writing 3 have been removed. The only option that I see to resolve this issue to to start to shop around for something other then Kiddie detectors. October 10, 2013
Rated 5.0 out of 5.0 by always great service and great products and prices easy to install,also home depot had great assortment of electrical connectors April 8, 2015
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