Section 3280.211 - [Effective 3/17/2025] Carbon monoxide alarm requirements(a)Labeling. Carbon monoxide alarms shall be listed and must bear a label to evidence conformance with UL 2034 (incorporated by reference, see § 3280.4 ). Combination carbon monoxide and smoke alarms shall be listed and must bear a label to evidence conformance with UL 2034 and UL 217 (incorporated by reference, see § 3280.4 ).(b)Required carbon monoxide alarm locations. Carbon monoxide alarms must be installed in each home containing either a fuel burning appliance or designed by the home manufacturer to include an attached garage. Carbon monoxide alarms must be installed outside of each separate sleeping area in the immediate vicinity of the bedrooms and in accordance with the alarm manufacturer's installation instructions. Where a fuel-burning appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm must be installed within the bedroom and in accordance with the manufacturer's installation instructions. Carbon monoxide alarms must be installed in conformance with NFPA 720 (incorporated by reference, see § 3280.4 ).(c)Interconnectivity. Where more than one carbon monoxide alarm is required to be installed, the alarm devices shall be interconnected in such a manner that the actuation of one alarm will activate all the alarms installed.(d)Connection to power source. Each carbon monoxide alarm must be powered from the electrical system of the home as the primary power source and a battery as a secondary power source.(e)Combination alarms. Combination carbon monoxide and smoke alarms shall be permitted to be used in lieu of carbon monoxide alarms. When combination carbon monoxide and smoke alarms are used, they shall be installed to also comply with § 3280.209 .(f)Basement applications. For each home designed to be placed over a basement, the manufacturer must provide a carbon monoxide alarm for the basement and must install the electrical junction box for the installation of this carbon monoxide alarm for its interconnection with other alarms required by this section.(g)Testing. Each required carbon monoxide alarm installed at the factory must be operationally tested, after conducting the dielectric test specified in § 3280.810(a) , in accordance with the alarm manufacturer's instructions. A carbon monoxide alarm that does not function as designed during the test and is not satisfactorily repaired so that it functions properly in the next retest must be replaced. Any replacement carbon monoxide alarm must be successfully tested in accordance with this section. 86 FR 2519 , Jan. 12, 2021 86 FR 2519 , 1/12/2021; 89 FR 75745 , 3/17/2025