It is ussually thought that if you receive a shock touching only one cable is because you are not well isolated from ground. In theory, if you touch only one wire in one point and you are not conected to ground, you should not get a discharge (we all have seen small birds in the transmission lines). However, I have noticed that if I am standing on a plastic stool and not touching the ground anywere and I touch a live wire with one of those test lights like a screwdriver used by the electricians, it indicates current. This tester is only a light and a very high resistance between the wire and my finger, and it is indicating that the current is going into my body (with small intensity due to the high resistance of the tester). I guess my body is acting like a capacitor or someting like that. It is possible to receive a painful or dangerous shock if you are not grounded, only by the capacitive effect?. And in a more general sense, if an large object (like a human body) is conected to one of the terminals of an AC generator but the circuit is open (no return cable) and there are no other objects close to the big body that can act as "the other plate of the capacitor", can there still be a current?. If the body is sufficient large, I do not find any physical reasons to think that this would not happen. However it breaks a bit with the common asumptions of the circuit theory.