Smoke detectors (alarms) are installed in single-family dwellings to provide early warning of a fire. Their installation is required by building codes in many municipalities and by many fire departments.
Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Questions can be sent to email@example.com. Answers are based on the 2014 NEC. Previous use of gray conductors