Hi. In a normal power plug, neutral is on the same potential as the earth and therefore, in theory, safe to touch. Line carries the full voltage difference and is dangerous if the body provides a conducting connection to the earth, since this closes the circuit to neutral. Isolation transformers essentially remove the connection of neutral to the earth, so one can only close the circuit (and get shocked) by touching both connections. I don't quite understand how this works in terms of voltage differences. If the voltage difference between the connections is 240V, at least on of the connections has a voltage difference of at least 120V to the earth. Why is there still no (potentially dangerous) current if one touches one connection (and is sufficiently connected to the earth)?