What is "floating voltage"? I've actually measured something myself... I've had my volt-tick sing three feet away from a device and I've seen 28 Volts RMS from a point of "ground" (light switch cover screw) to nothing but mid air, and I've had metal framing in a milk parlor measure well over 30 volts to wet concrete and was shocking my Mom while she milked the cows. (Bonding fixed that).
I'm reasonably familiar with equipotential planes as far as bonding a grid embedded in a concrete floor, but I've never installed one.
I digress... What am I measuring? Is it this phenomenon known as "floating voltage" and just what is it? Is it created chiefly by induction and/or poor grounding?