I have a question about the section 'Shock Current Path' (http://www.allaboutcircuits.com/vol_1/chpt_3/3.html). On the fourth picture, I didn't understand why the person was not shocked. If a person touches a wire connected to a source and is standing on the ground, wouldn't that form a circuit itself (i.e. generate voltage between the source and ground)? Does that mean that the ground always has an equal potential to wherever it is connected to? I'm confused.