wrote in message
stuff snipped

As for the OP, what was legal in the 70's is moot.

Except the upgrade was likely done either during or before the
seventies. - so not ENTIRELY a moot point. It was "standard practice"
and "approved" when it was done.

I was referring to the guy (OP - original poster TomR) who started the
thread asking about how to turn a two pronged outlet into a grounded one. I
think he did exactly the right thing - had a new cable with ground run.

I agree, in the 70's you were not likely to run into the problems you might
today tying into a clamp-on-pipe ground connection.

Not to say it should not be redone today.

I ran along every inch of the water pipe and removed and rewired the
surprising number of grounding clamps that were sitting on the pipes. CATV,
phone, upgrading outlets, etc. after I tore the entire ceiling down.
Virtually every clamp connector showed some sort of corrosion or physical
damage to the (very old) copper pipe.

--
Bobby G.