SKU: 1039832

Regular price $69.99

Shipping calculated at checkout.


The First Alert SA520A Interconnected Smoke Alarm with Hardwire Adapter Included allows you to create an interconnected fire alarm system without the cost and hassle of wiring. Use this smoke detector to replace an existing hardwired smoke alarm and then install additional First Alert Wireless alarms for an interconnected safety network (additional alarms sold separately). This hardwired smoke detector can connect and communicate with up to 18 compatible alarms, so when one alarm is triggered, the entire system reacts. An integrated battery backup ensures the smoke alarm continues to work even during power outages.

Create an Interconnected Fire Safety System

The Alert SA520A Interconnected Smoke Alarm with Hardwire Adapter Included makes it easy to begin creating a safety network of detection. This model is designed to replace an existing hardwired 120-volt alarm so you can add up to 18 First Alert Wireless Interconnected alarms and get expanded protection (additional alarms sold separately). By connecting multiple Wireless Interconnected alarms, you can be alerted to danger on the other side of your house before the smoke from that area reaches you. When one alarm sounds, all connected alarms in the system will sound simultaneously. Earlier notification of danger means you can escape sooner.

Hardwired Alarm Installs Easily

The smoke detector is designed for non-professional, do-it-yourself installation. It is designed to easily replace most existing 120-volt hardwired alarms. In case of power outages, the smoke alarm has a battery backup feature designed to ensure continuous detection. A low-battery light and chirp will let you know when the AA batteries need to be replaced. A one-touch button silences false alarms and allows you to test the smoke alarm for functionality.

Comprehensive Warning Features

The smoke alarm features an 85-decibel siren. This smoke detector uses a photoelectric sensor that is designed to detect the presence of smoke, while minimizing false alarms from cooking smoke and shower steam.


Model SA520A
Sensor Type Photoelectric
Sensor Information Smoke particles of varying number and size are produced in all fires. For maximum protection, use both ionization and photoelectric sensing technologies. Ionization alarms are generally more sensitive to fast flaming fires and photoelectric alarms are generally more sensitive to smoldering fires.
Power Source Hardwired
Battery Replaceable Yes
Backup Battery Size AA
Sound Level 85dB at 10 feet
Product Height 5 in, 127 mm
Product Length 5 in, 127 mm
Product Width 2 in, 51 mm
Product Weight 1 lb, 0.45 kg
UPC Number 029054018984
Warranty 10 Years Limited
Features Battery Backup, End-of-Life Warning, Hardwire Interconnectivity, Hardwire Quick Connect Plug Included
Type Smoke Alarm