Instead of using a polarized plug on lamp cord, use three wire cord with a three pronged plug and a proper metal electrical enclosure obtainable from any home improvement store. Attach the ground wire from the cords to the ground screw of the metal enclosure. Also, a plastic enclosure could be substituted. While we liked the idea of this project, our readers have brought to our attention too many possible safety concerns to let it stand as is. If you are not knowledgeable in proper home AC wiring practices, we do not recommend building this project. You can join in on the discussion in our forum, if you are so inclined. http://forum.nutsvolts.com/viewtopic.php?f=39&t=17062
Happy Holidays and above all, be safe!