florinc:
Isn't a current sensor, like this one
http://www.seeedstudio.com/depot/noninvasive-ac-current-sensor-100a-max-p-547.html?cPath=144_154
a much safer and reliable option for this purpose?
I was going to ask, the circuits being discussed only detect if the appliance is powered if the appliance is switched by some external switch, and the same switched power is fed to the detector circuit. Some sump pumps are one example of this, but I'm not thinking of any others off the top.