Eddie, I see you list yourself as an Electrical Helper. I want to impart some wisdom on you, with no intention of sounding preachy or condescending. We don't know here, what kind of lead men you work with and whether they are good instructors so...
The largest thing I pound in to the heads of new electricians is never touch a wire you have not personally verified to be dead! That is also the second rule. I am telling you this because reading through this thread it has jumped out at me. Some of the questions and answers go toward wire color etc. That is like, "is a green wire always ground?" The answer is absolutely no! The green wire is exactly what the installer wired it up to be. I have seen the bare wire in a romex used as a traveler in 3 way switches more than once.
All that said, the indication that you use a meter should be the definitive answer. In my opinion, all people working on electrical systems should have a meter. They should be trained in how to use it. FIRST! It can be a 20 dollar really cheap meter to start. I have a habit of telling helpers/apprentices all of this and over and over pounding in that you don't touch until you personally verify. I will regularly tell an apprentice, "Go over there and disconnect that box, I already checked it. It is dead." I will then watch and if they actually disconnect without touching, I will council them and try again. A "tick" tracer is not good enough. Always check your meter on a known live source first, and then on the circuit you are testing and then on a know live source again. I have personally seen a meter fail in between tests. Your life is not worth the few seconds you save by short cutting.
That test also works with 1ph VS 3ph.
