Underwriters Laboratories(UL) is a company that tests and rates products for safety standards. In terms of lights and ceiling fans, the rating tells you what types of locations it is safe to install the product in. There are three UL ratings that are relevant to ceiling fans and lights. The ratings are Dry, Damp and Wet. This post will help you understand what these ratings mean.
A UL Dry area refers to a location indoors that will not be exposed to damp conditions. Temporary dampness is acceptable assuming there is proper ventilation that eliminates the possibility of moisture accumulating. Common dry areas are bedrooms, halls, a foyer, your kitchen, dining areas and living rooms.
Only lights and ceiling fans with a UL Wet rating are safe to install in gazebos, decks, exterior dining areas, patios, porches that are not covered, indoor pool rooms, outdoor walkways or any area that may be rained on. Wet locations may be both interior and exterior areas. If the fixture might get wet during a storm, having liquid drip on it, or may be splashed be sure it is UL Wet rated.
A Damp rating means that the product is suitable for an area that may have occasional moisture or condensation. If your fixture will be installed in an exterior area it must be in a location that completely protected from water even during strong winds or storms. Areas that should have a UL Damp rated product are enclosed porches, bathrooms, utility rooms, and pool storage areas. As long as it will not be possible for water to directly come in contact with the fixture they can be installed in greenhouses and barns as well.
Final Notes on UL Ratings
If you live in a climate with high humidity, you should make sure all your exterior fixtures are UL Damp or UL Wet rated. Products rated for wet and damp locations can be used in dry locations. However, UL Dry rated products cannot be used in damp or wet locations. Products that are to be placed in commercial areas should especially respect UL ratings.