Ummmmmmm working something as dead without gloves or grounds is just plain foolhardy.There are so many things that can go wrong that it would take a book to list em all.As far as that extra wire is concerned they may be using it for the lightening arrestors, or the circuit could have been wye at one time.Ask yourself if they were to built a primary extension for a span or two would they also string in a neutral along with it? Its been my experience that a great many of the oilfield hands are not linemen but shade tree electricians.