Question again Please.

[rick711]

Hello, and thanks for all of the help that I have been getting from everybody,

I asked and electrician at my work that I was watching work on an installation
(careful not to bother him, I do not like anybody looking over my shoulder watching
me work). He said that he was installing a transformer and that the 480 VAC 3 phase
panel that he was going to feed it from did not have a "grounding conductor" ran to
it in the conduit. He said that it was using the conduit itself as a ground. I saw that
after he was finishing up that he had ran a green wire that I am thinking is ground
from the panel ground terminal to the transformer. ????
Can you do this, because there is not a ground coming into the panel. I know that
he said that the steel conduit is the ground. I am asking for one, I do not know yes or
no and two this green colored conductor that he ran from the panel to the small
transformer went to the ground terminal that had a ground symbol on it, but then
it also when from there to a small panel that he also mounted to the wall next to
the new transformer. I am do not want to ask him too much, this is due to he does
not give out much info on electrical. I will just say that he flies off the handle quickly
and he is the only electrician that works there, so I talk to him when I get the chance.
I wrote a book here, I am learning a little each time, it is slow going/trying.

 

[zbang]

He said that it was using the conduit itself as a ground.

That's just fine in most cases.

he had ran a green wire that I am thinking is ground from the panel ground terminal to the transformer.

Yes, correct.

This all sounds correct to me.

 

[augie47]

agree with zbang. sounds correct.
From the 480 panel you would have an equipment ground to the transformer. This could be an actual wire or, in many case, the conduit.
From the secondary side of the transformer there is a similar conductor which is a system bonding jumper and likewise it can be a wire or the conduit.
There are a lot of specifics that would be relative to the particular installation but that's a summary.