I would recommend that everyone plugs their heat box into a GFCI protected outlet - because you were miss informed by Orcbow - because the way a GFCI works is off the neutral wire , any leakage of current trips it and the neutral not the groundwire is the current carrying conductor - so if there is any fault whatsoever in the wiring and or breakdown of any components -the GFCI will pickit up and shut the power off -great insurance . A GFCI only monitors between the hot and the nuetral , so anythig thats plugged into it doesn't neccessarily need a ground for it to work . Something I do for a living ,Lol !!!
Paul
LU # 43
3rd generation electrician