According to the National Electric Code (NEC) article 800-179, which cable marking indicates that a cable is riser-rated?

A cable marking of "CMR" indicates that the cable is riser-rated according to the National Electric Code (NEC) article 800-179. Riser-rated cables are specifically designed to prevent the spread of flames within vertical spaces, such as between floors in a building. The "R" in "CMR" stands for "riser," highlighting its suitability for installation in these applications where vertical routing through walls and ceilings is necessary.

Riser-rated cables, like those marked with "CMR," have been tested to meet specific fire safety standards, ensuring that they can resist flame propagation and minimize the risk of fire spreading to other floors. Understanding this classification is crucial for ensuring compliance with safety regulations and selecting the appropriate cable for the environment in which it will be installed.