What is mandatory for outdoor electrical installations as enforced by WAC?

In outdoor electrical installations, it is essential that equipment is weather-resistant. This requirement is in place to ensure safety and reliability in varying environmental conditions. Weather-resistant equipment is designed to withstand elements such as moisture, wind, and temperature fluctuations, which are prevalent in outdoor settings. Using standard indoor-rated equipment in outdoor applications could lead to failures or hazards, as indoor devices are not built to handle exposure to the weather.

This requirement is critical for preventing electrical malfunctions, reducing the risk of electric shock, and ensuring the longevity of the installed systems. Weather-resistant equipment often includes features such as sealed enclosures, protective coatings, and specific materials that resist corrosion, ensuring that the installation remains safe and operational for an extended period.

The other options, while they may seem plausible in various contexts, do not comply with the established safety protocols for outdoor installations. Therefore, the adherence to using weather-resistant equipment is a fundamental requirement enforced by WAC for outdoor electrical work.