On Thu, 14 Nov 2013 19:39:38 -0600, dpb wrote:

the third wire is the ground but NEC until
relatively recently allowed the ground to also be the neutral

You seem to understand this better than I do.

The way *I* understand a "ground" is that a ground wire carries no current
(unless there is a problem). The "neutral" wire, on the other hand, *always*
carries current.

That's a pretty big difference (as I understand it anyway).

More specifically, the way I understand a ground wire, is that it goes
from the receptacle in the wall to the main breaker panel, where it
literally is driven directly into the ground (usually by some kind of bar).

In contrast, the neutral wire, as I understand it, goes to the same
breaker panel, but then it goes from there to the power pole, and then
from that pole it may travel hundreds of feet to a few more power poles,
but eventually, it too is driven straight into the ground.

The difference, as I understand it, is that the ground never carries
current (unless there is a fault), while the neutral is always carrying
current (and therefore it might have a potential on it).

Given that they're not at all the same thing, I then have trouble
understanding the statement that the ground is "also" a neutral.

Again, you seem to understand better than I do, but, the way I
described it above, a ground and a neutral are totally different
things.

So, I don't understand how a ground can 'also' be a neutral.