No, you don't need any extra wires if your getting the cord from bean farm. I *think* bean farms cord comes with one set of clips, so all you should need is a simple dimmer you can get at the hardware store.
I put mine on wheels and wanted an electrical connection that could stand up to some movement of the rack. I ran two strips of tape up the back of the rack. I used an extension cord as the cord, I just cut off the female end of the cord. I used liquid electrical tape on the connections, but was not pleased with that, so I also capped all the connections with regular electrical tape. (Check and make sure clips come with your cord or go get some electrical tape) Then I spliced the dimmer in the line and plugged each length of tape into the thermostat. I set the thermostat probe actually ON one of the strips of heat tape. If they tape itself exceeds 95-97F the thermostat shuts off both strips until the temp drops some.
Does that answer your question?
