What type of low-voltage lighting system can permit a lesser cover depth than required?

In the context of low-voltage lighting systems, a listed system refers to equipment that has been tested and certified by an organization recognized by the National Electrical Code (NEC). These systems have been evaluated for safety and performance, and as a result, they are permitted to have lower installation requirements, including a lesser cover depth than typically required for standard installations.

This provision is particularly important as it allows for more flexibility in installation procedures while ensuring safety standards are upheld. The listing signifies that the product conforms to specific safety requirements that justify its reduced cover depth, which would otherwise not be acceptable for non-listed or general equipment where higher cover depths might be necessary to mitigate risks such as damage or interference.

In contrast, non-listed equipment does not have this level of certification and, therefore, must adhere to the more stringent cover depth requirements. The distinction between listed and non-listed systems is crucial and directly influences the installation practices allowed under the NEC, emphasizing the importance of using properly certified products for electrical work.