To add to this A trouble light already has an ext. cord attached and the heat from it rises right up where the gauges are. Maybe less of a safety issue. I think the warning on the fan heater was in general for people that might use wimpy cords. Go with 12 gauge wire and its no different than the 50-100 ft of 12gauge running through the wall. Heck, most hangers wall plugs are probably 14 gauge. A tight duplex is needed so there is no arcing or resistance ,hence creating heat.