Wet Location? Damp Location?

Posted: Thursday, September 2, 2021
By: Gillespie Electric, Inc.
Categories: Commerical Electric

Wet Location? Damp Location?

It’s important to know the difference because installing the wrong electrical equipment is going to be discovered during the final inspection and just when the electrician was packed up and ready to move on to his next project.

It’s easy to recognize when a dry location luminaire is installed under a porch roof because it has a load of bugs already piling up inside the lens. Under the roof of a porch is exterior to the house and is exposed to the outside air that is not conditioned air. For this situation install a luminaire that is listed for damp locations. This will be printed on the outside of the box. Once the box is open you will see additional labeling or printing right on the luminaire itself. Everyone should be up to speed on the term luminaire since several issues ago the NEC stopped using the term “fixture” and “light fixture” and uses luminaire instead. So a luminaire listed for damp locations is going to be gasketed and better sealed to prevent dust, bugs and moisture from getting in.

For wet locations lights this too will be marked on the shipping box as well as on the luminaire itself. We location luminaires are sealed up to a higher degree yet and are designed to get rained on and still operate without any problems.

The problem the installers and the inspectors seem to have a disagreement about is just what constitutes a damp location vs. a wet location. I can’t remember where I heard about this guideline but I have always used it while inspecting and it has served me well in my career. I once ran into an electrician who insisted he did not need to install an in-use or “bubble” cover for a receptacle because he installed the receptacle under an overhang on the front wall and sixteen feet above the receptacle location. It was easy for me to determine that this indeed was a wet location and the in-use cover was installed.

So a better technical way for all to determine damp vs. wet location is this. Draw or visualize a line or the rain hitting the building at a 45˚ angle. If the receptacle or luminaire location is below the 45˚ line it is a wet location. That simple.

Electric Education Center

967-A Bristol Pike

Bensalem, PA 19020


Tagged:Commercial Electric

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