Under NEC Article 300, what is required for conductors that are exposed to wet locations?

For conductors that are exposed to wet locations, the requirement is that they must be rated for wet locations. This means they should have appropriate insulation and jacket materials that can withstand moisture and prevent deterioration which could lead to electrical faults or hazards.

Conductors rated for wet locations are designed to resist moisture penetration, corrosion, and other potential damage from the environment. This makes them essential for ensuring safety and functionality in areas exposed to water or high humidity.

The other options suggest alternatives that do not meet the specific requirements outlined in the NEC. For instance, while underground installations might be common in certain environments, not all wet locations are underground. Similarly, while rubber insulation is a good protective option, it is not the only material that can provide the necessary protection, nor is it a requirement for all conductors in wet locations. Lastly, using any type of conductor without consideration for its wet location rating would be against safety codes and could lead to serious electrical risks. Thus, being specifically rated for wet locations ensures compliance with safety and performance standards for electrical installations in these environments.