miller, as much as I appreciate 99% of your posts, I’m not sure how you defend your position on this. It’s simple. The ground is the only safeguard in the event that any metal item becomes energized due to an equipment defect or failure.
You're right it is pretty simple. The two wires in a two wire system, only one of them is hot. That's your 120V. The other wire is ground. Technically called neutral but this brings up the first redundancy. There's ground where any voltage potential goes into the actual earth ground. A rod driven deep into the ground. The neutral wire is also ground, only in the common layman's sense of grounding. I don't always get all pedantic in explaining. The ones who know will understand and the others will get triggered and then I can pick and choose whether to ignore the ones who get triggered or try and explain.
I say try because it hardly ever works. Oh well.
I don't by the way have a whole lot of respect or patience for "code". Having learned from a journeyman electrician and having wired a whole house, twice, my experience with "code" is some moron making you re-do a whole weeks work because he thinks you should have an extra 1" of wire in the box. Or 1" less. They are that retarded. Meanwhile, in other "code" I have to install hurricane clips to hold my roof on. We have yet to record a hurricane in Seattle. Code can, as the Robert Duvall character in Jack Reacher would say, "Suck it!"
Our house was built in 1952. I can't tell you what the code requirements may have been then. Jim may know. Everything was wired with two-conductor cables, forerunner of romex, I guess. All the boxes, etc, were metal, and they all were connected with a dedicated ground wire, one to the other.
Wonderful story. Really. Charmed. What that has to do with anything I haven't the foggiest.
Look. Those old homes. Forget the metal boxes. Forget they are connected. Forget they are grounded. Why? Because I want you to think of something evidently never occurred to you before.
All those outlets they have how many plugs again? Oh yeah- two. And the stuff you plug into them? Two wires, right? One hot, one neutral. Just like I said.
So now here's the question: When your whatever it is connected with two wires somehow gets energized, of what use exactly is the metal outlet box being grounded? Anyone? Beuller?
None. None at all. What happens is the component, the whatever it is, the neutral wire carries the charge right back to the utility ground. Just like it always does. Which is why nobody electrocuted themselves all those decades using the old system.
Never had anything to do with the outlet boxes being grounded. That my friend is what we call a redundancy. Never did have anything to do with the safety of the stuff plugged into it. Not until the third wire came along. Technically, not even then. The third wire, the true earth ground, is merely another redundancy.
What happened, as if anyone cares, is people with real lives became so wealthy and so comfortably numb they didn't care when the morons who think 1" more or less in the box really matters came along and said, "You've got millivolts of voltage potential on that neutral wire, we can eliminate that infinitesimally micro risk that hasn't caused a single death in a million man-years." And we said, "I don't have the foggiest what "potential" means but "voltage" sounds scary so yeah sure go for it."
So now you know. That's how I defend my position. By being right. Works every time.