How does the NEC® define an installation that is located inside a building?

The National Electrical Code (NEC®) defines a "dry location" as an area that is typically protected from moisture and has no potential for exposure to water, such as those found within buildings. An installation within a building is generally considered to occur in a dry location because the inside of buildings is typically climate-controlled and shielded from outdoor elements, which would include moisture and water.

This definition is significant for electrical installations because it affects the type of materials and equipment that can be used. For instance, wiring and devices allowed in dry locations may differ in terms of ratings and suitability when compared to those designed for wet or damp locations, which may require more stringent protections against moisture.

In contrast, a wet location would be an area exposed to direct water or moisture, like outdoor installations or areas prone to flooding, while a damp location would have moderate moisture levels, like basements or areas prone to humidity but not directly exposed to water. A non-hazardous location doesn't specifically categorize the location based on moisture but rather touches upon the safety and environmental risks associated with electrical installations. The specific classification of dry locations, therefore, is crucial for determining safe and compliant electrical practices within buildings.