2 Wire Hardwired Smoke Detector
A hard-wired smoke or carbon monoxide (CO) alarm is wired to a 120V household electrical circuit and is connected to other detectors throughout your home. Hard-wired smoke and carbon monoxide alarms sound simultaneously, on all levels of your home, when a single unit detects smoke or gas. Units with battery backup provide extra protection by functioning even if a fire causes the power to go out.
While most local building codes require hard-wired smoke alarms in all new construction, there’s added security and protection if you’re installing one in an existing home, and the steps are the same whether you’re installing smoke alarms or CO alarms.