This Literally just happened to me also. My mother was playing with the switchboard thing and it looks like she must have caused the plug to short, that, coupled with the fact that I don't unplug my heater (I always shut it off, but don't unplug it). The plastic on my heater outlet was completely burnt, and it looks like any more time and I would have started an electrical fire. Me never being home and also being a very heavy sleeper, well I could have been much worse off. Make sure you unplug things when you aren't using them, and always check your plugs if something seems off!
Danny
November 2012