The title of your question is rather starkly phrased. Since most electrical engineers working in industry do not have PhDs, clearly a PhD is not "really necessary".
There have been a lot of questions asked about this on the site already, which you may want to look into. In the absence of more specific information, one can only answer in general terms. What I would say is that PhDs are first of all for people who want academic careers and second of all for people who have a good, specific idea of what non-academic career they want and how the PhD will help them with it.
If your goal is to work in industry as an electrical engineer, I would try to realize that goal as soon as possible: i.e., as soon as you have a bachelor's degree in electrical engineering. Then you can find out whether you really like it, get experience and so forth. You'll have a much better idea of the pros/cons of coming back for a PhD after spending time working in the field, you'll have plenty of people to ask about it, and you may even get financial support from your employers (so that for instance you may not need to do the teaching and grading that other grad students will, though as I type this I realize I don't know how much EE grad students teach or grade).
