Let me be the first to suggest terminology clarification:
[1] The ungrounded conductor becomes the "power conductor"
[2] The grounded conductor becomes the "neutral conductor"
[3] The equipment grounding conductor becomes the "safety conductor"
If only it were that simple. :happysad: And you are far from the first, even for this exact combination.
1. There is no "the" ungrounded conductor. There may be three in three-phase, four in two-phase, either two or one in single-phase, etc. So there would be power conductor
s. But the grounded conductor would be just as much a path for the power as the ungrounded conductor. It does not really convey the distinction. Maybe since it is not bonded to the safety conductor, it would be an unsafe conductor.
2. Not all grounded/earthed/safe conductors are neutral conductors, and in a few special cases neutral conductors are not necessarily grounded. Try again for that one.
3. That makes some sense, and it at least has the advantage of starting off with a new term that does not have a lot of baggage associated with it. But there is the common usage of the "safety ground" as distinct from the grounded circuit conductor. And, of course, the fact that it is a safety "ground" does not convey that what is important is that it is a fault clearing conductor with the secondary purpose of minimizing the touch potential between metal equipment parts and shells and other things in the environment, both during and separate from a fault.