Can I get 120v from one hot wire to the neutral an a 3 phase panel?

Depends.
What 3-phase system is it? And WHY are you working on a 3-phase system to begin with?

Franco,

Your questions are really basic level questions and for the most part are fine.

However, 3 Phase Power Sources are normally handled by licensed electricians.

Three phase can be very deadly for one thing also, if the "Hi Leg" is connected improperly, just about every 120 device on that phase bar will get toasted.

So I have to ask, are you qualified and have you studied three phase transformers and panelboards?

Franco, that question can not be answered without knowing specificly what 3phase system you have.

Honestly I don't know if is delta or why I only know that is 4 system.Don lots of my questions are basic yes and I lot of them I already know it just want to make sure. I have't work with 3 phase system ,most of my work that I have done is in residential,my friend and I are working in this but, he has more knowledge in this that me.If I ask you a question is because I want to learn that's why I ask you not, trying to be rude I appreciate your help, and I love working with electricity I am fasinate by it.I ask questions because I want to lear is much it I can.Is delta and why systems are both have a hig leg?And how do you identify which system is which delta or y?THANK YOU VERY MUCH GUYS.

Measure voltage between each hot legs and each leg to neutral, any colors of tape on conductors?

NO,all of them are black except one has the white tape.

Strat asked two questions for a reason:


Measure voltage between each hot legs and each leg to neutral,