BRK SC9120B Smoke & Carbon Monoxide Alarm, 120V Hardwired w/ Battery Backup

SKU: 90109
Brand: BRK Model: SC9120B Condition: New

BRK SC9120B Carbon Monoxide & Smoke Alarm

Regular Price: $47.99
On Sale: $33.60

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View All BRK Carbon Monoxide & Smoke Alarm


The BRK SC9120B is a great choice when it comes to affordable smoke & carbon monoxide combination alarms. Redeigned from the ground up, BRK created the SC9120B model to directly replace past models while providing greatly improved sensing technology, improved installation method, and improved connectivety. All around, the BRK SC9120B is the perfect combination alarm if you are looking for affordability with function. The SC9120B uses a superior Carbon Monoxide sensor and a dual Ionization sensor for smoke.

The SC9120B model has the ability to be interconnected within a circuit of alarms and other alert devices such as bells, whistles, repeaters, fans, or switches. (You can connect up to 17 devices, of which 11 can be smoke alarms, and 6 can be alternate devices.

Also integrated is a 9V battery backup to make sure your smoke alarms do not loose operation when your power fails, providing addtional security.

Note: This item is the DIRECT replacement for the discontinued BRK 4120, 4120B, and 86RAC


• Intelligent Sensing Technology: Reduces the number of non-emergency or unwanted alarms
• Interconnectable: 18 units. Can be interconnected with up to 12 smoke alarms and the remaining can be a combination of UL listed BRK heat, CO alarms
• Latching Alarm Indicator: Easily identifies initiating alarm even after the alarm condition has subsided
• Perfect Mount System: Includes a gasket less base for easy installation and new mounting bracket that keeps the alarm secure over a wide rotation range to allow for perfect alignment
• Smart Interconnect: One interconnect wire carries smoke and CO alarm signals
• Smoke & CO Combo Unit: One alarm protects against two deadly household threats
• Two Silence Features: Can temporarily silence low battery chirp for up to 8 hours before replacing low battery or silence an unwanted alarm for several minutes


• Audio Alarm: 85dB at 10 feet
• CO Sensor: Metal Oxide
• Humidity Range: 10% to 90% relative humidity
• Operating Voltage: 120V AC w/ 9V battery back-up
• Power: .09 Amps
• Smoke Sensor: Dual chamber ionization
• Temp Range: 40 degrees F to 100 degrees F
• Wiring: Quick connect plug with 8" pigtails

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Questions & Answers

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Can these BRK alarms be interconnected?

by Kevin M. on 03-13-2014

Yes, the BRK SC9120B model has the ability to be interconnected within a circuit of alarms. You can connect up to 17 devices, of which 11 can be smoke alarms and 6 can be alternate devices.

on 03-17-2014

My First Alert SCC9120B were all going off, but there was no fire and no carbon monoxide issues. Therefore, I changed all the batteries thinking that was the problem. After installing the new batteries, a few minutes went by and then one of the alarms started three beeps and soon after the other followed. Do I need to reset these alarms after installing new batteries or what would you think my problem may be?

by Brian H. on 02-23-2014

Smoke and carbon monoxide detectors have a shelf life of 7-10 years, if it has been longer than that we recommend purchasing new ones. If they have not been installed that long, contact the manufacturer directly to troubleshoot the unit. First Alert phone number: 800-323-9005

on 03-07-2014

Does this carbon monoxide and smoke alarm have voice warning?

by William R. on 02-01-2014

No, this unit does not have voice warning. The BRK SC7010BV is the unit with voice warning.It can be found here:

on 03-17-2014

do i need to connect this to any A/C SOURCE OR the battery is all i need? AND I AM LOOKING DETECTORS FOR A SCHOOL

by Kenneth.e.m H. from Antigua and Barbuda on 05-02-2013

The unit should be hardwired directly to the home/business. Though the battery will power the unit by itself.

on 05-02-2013

do i need to connect this to any A/C SOURCE OR the battery is all i need?

by Kenneth.e.m H. from Antigua and Barbuda on 05-02-2013

This unit is wired directly to your home. The battery will also power the unit by itself.

on 05-02-2013

Is the BRK9120B a direct replacement for the SC6120B ?

by Kenneth B. on 04-09-2013

The 9120 Series will replace the SC6120B model

on 04-09-2013

Will this SC9120B EASILY replace the old 86RAC? Does it have the same hardwire plug so I can use the old plug? How about the hardware on the ceiling to attach it?thanks in advance! Andy.

by andrew K. on 04-05-2013

The 86 RAC is Replaced by the BRK 9120B.

on 04-05-2013
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