Thursday, March 19, 2009

Subject: Outdoor wiring


Name: Anthony


Question: Hello, I’d like to hang a ceiling fan from the underside of the roof covering my outside deck. There is already a 20 amp circuit with a GFI receptacle installed. I plan on connecting to the load side of it, feed it into a fan/light control switch with weather proof cover and run 12/3 to a ceiling fan. The existing circuit is in conduit, which I plan to extend up to the rafters, but then run the 12/3 along the underside of the roof to the fan. I was told I need to install UF cable since it is outside. The only way the cable could get wet is if the roof leaked. Is it OK to use NM-B for this application?


Answer: Anthony,No you really should use UF even if it is outside under a roof. You still can have driving rain in a wind storm the can get to the underside of that roof. There is also fog and mist that can also get to that wire as well. UF is designed for the elements NM is not.

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