I am going to install several recessed lighting fixtures in my porch ceiling. Do I need to use wire rated for exterior use? I know I need to buy exterior rated fixtures. Anything else I should know???
My answers are based mostly on the ICC codes. Advice given is my personal opinion and every person performing work should acquire a permit from his/her jurisdiction and get the work inspected. My opinions are not directions to follow for DIYs or professionals
Is the porch ceiling enclosed or open?
Neither the cans nor the wire need to be outdoor rated.
The cans are aluminum, they won't rust, and they are recessed into the ceiling and therefore not exposed. (Do they even make outdoor rated cans?) The trims however should be rated for use in a damp location. This will help to protect the fixture and keep the bees out. (These are the trims that have glass over the bulb and are rated for such use.) The wiring is in the ceiling of your porch is not exposed to rain so 14/2 romex is fine.
Assuming your talking about a farmers porch (essentially a deck with a roof over it just so we're clear) I have done this many times and not one inspector has ever said anything about the romex wiring.
The only thing thay MAY have to be rated for damp location is the trims.
Here in the desert we can use standard trims as a porch ceiling would not be "normally subject to dampness".
Article 100 Definitions-
Location Damp- Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.
So using this deffinition your farmers porch you could not use NM (romex)cable.
Types NM and NMS cables shall not be used under the following conditions or in the following locatons:
(1) Where exposed to crrosive fumes of vapors.
(2) Where embedded in masonry, concrete, Adobe, fill, or plaster.
(3) In a shallow chase in masonry, concrete, or adobe and covered with plaster, adobe, or similar finish.
(4) In wet or damp locations.
Now lets look at Luminaire Locations per the 2008 NEC
Article 410.10 Luminaires in Specific Locations
(A) Wet and Damp Locations. Luminaires installed in wet or damp locations shall be installed such that water cannot enter or accumulate in wiring compartments, lampholders, or other electrical parts. All luminaires installed in wet locations shall be marked, "Suitable for Wet Locations." All luminaires installed in damp locations shall be marked "Suitable for Wet Locations" or "Suitable for Damp Locations."
Again Farmers porches are Damp Locations (as per the 2008 NEC)
Now looking at the fact that you are using recessed cans I dont think you are installing them in a Farmers Porch since you would see the can and the trim in this kind of application.
Most inspectors agree that as long as you have a ceiling in the porch that area above the ceiling is not a wet or damp location with these code sections Ive quoted.
Last edited by codeone; 12-17-2009 at 04:20 AM. Reason: clarify
Another thing you can do Is speak with your local inspector and ask questons.
If he is a good inspector doing his job he would happly be willing to help you as a Public Servant he is supposed to be.
Granted some let the power of authority go to their heads and are not very helpfull. But you also have to realise that we can only tell you if something meets the codes we cannot tell you how to do the job. If we were to tell you how to do the job we would be engineering which is beyond the scope of our certificatons.
There is almost always more than one way to meet the codes. Also remember the codes are the minimum requirements to have a reasonably safe installation.
Have a good day!
Last edited by codeone; 12-17-2009 at 04:34 AM. Reason: spelling