How must luminaires be installed in damp or wet locations, according to Article 410?

In damp or wet locations, luminaires must be specifically listed for those conditions to ensure they are suitable for use where moisture is present. Additionally, the installation must be done in a manner that prevents water accumulation. This requirement is critical because water can lead to electrical failures, corrosion, and potentially hazardous situations if the fixtures are not designed for such environments.

Using fixtures that are appropriately rated for damp or wet conditions guarantees that they are constructed with materials and designs that resist moisture penetration and can tolerate the humidity levels typically found in those environments. The design considerations might include sealed components or protective coatings that help to prevent moisture-related issues.

The other options do not align with the NEC requirements for installation in damp or wet locations. Direct contact with water is not advisable since it can lead to electrical hazards. Open fixtures might seem like they facilitate airflow, but they do not necessarily address the need for proper sealing against moisture. Oriented fixtures for drainage can be beneficial, but without proper rating for the environment and preventative measures against water accumulation, this can still lead to safety concerns. Overall, ensuring luminaires are listed for the specific conditions and designed to handle moisture is key to safe and effective installation.