Originally Posted by lschiavo
I think you are correct. With a 1-pole device a difference in current between hot and neutral will trip the device and I like your explanation. But, theoretically if one were completely ungrounded you would have no fear of touching one leg, and if you touched 2 legs of a gfi device you would become the circuit and there should be no way for the device to sense a fault.
If you are not grounded and you get between the hot and neutral or the 2 hots in a GFCI protected system you have become the load and all the GFCI device knows is that there is a load connected to it and that there is no leakage to ground there for it will not trip. It Dose not know if it is a toaster or a person on the end of those wires and will not trip until it senses leakage to ground.
I don't understand most of this. But I guess this explains why I needed the GFCI, or at least why you strongly suggested I have it.
I will say this. I am almost always barefoot, unless it's cold. And my first two brewdays on my new HERMS rig involved water EVERYWHERE. The whole "close the ball valve before disconnecting the disconnects" seems to be too difficult for me to remember.
Safety is paramount. You probably don't need a fire extinguisher in your kitchen, either. But no one who has one is sorry.