First Alert SMCO600NV-AC

SaferProducts.gov consumer incident report 20260721-417DF-2147313607. Severity: Incident, No Injury. Product: First Alert SMCO600NV-AC (First Alert SC5 hardwired combination smoke and CO alarms (model SMCO600NV-AC, retail SKU FSMCO600NVACCL1)). Incident: I am a professional firefighter with fifteen years of service. I am reporting a pattern of defective behavior in First Alert SC5 combination smoke and carbon monoxide alarms installed in my own residence. I purchased six First Alert SC5 hardwired combination smoke and CO alarms (model SMCO600NV-AC, retail SKU FSMCO600NVACCL1) from Best Buy on July 1, 2025, delivered July 3, 2025. All six units carry the same manufacture date code, 2025 JUN 13, indicating a single production batch. Recorded unit identifiers include MAC IDs [REDACTED] and [REDACTED]. These alarms replaced six [REDACTED] alarms that operated in the same rooms, on the same household wiring, using the same ceiling boxes, for approximately ten years. In that decade the [REDACTED] units produced zero false alarms and zero connectivity failures. Since installation, the SC5 alarms have entered full alarm state repeatedly with no smoke, fire, or carbon monoxide present. Events have been recorded in the First Alert app activity log. At the time of each event there was no cooking, no shower steam or elevated humidity, no dust, and no sanding, painting, demolition, or renovation activity in the residence. Multiple events occurred overnight with the household asleep. Alarms have originated from units in at least four separate locations in the home. The alarms have also repeatedly lost network connectivity, dropping offline and returning without explanation despite running a top-of-the-line Router with perfect signal strength, and no other smart devices experiencing such issues. Separately, the First Alert app's alarm scr