what is the difference; other than the grounding prong receptacle, in the 2 and 3 prong appliance modules?
do you have to have a ground(third prong) with the three prong or can you use a two prong(sans ground) in it also?
if so, why make the two?
Or is there internal wiring differences that use the ground wire for current switch/safety as for as X10 is concerned thus making the 3 prong(module) useless when a two prong cord is inserted?