Hi,
if you run two grounds to an IG outlet the IG ground connects to the yolk/strap of the recept....right? egc connects to the box...right?

so do i not need an insulating material between the yolk of the recpt and the metal box to isolate these two systems?

i almost feel guilty getting all this free advice!

thanks for any replies.

-regards

Mustang

Mustang, An IG rect already has the yoke insulated from the the IG ground terminal.

Al

Your going to find that you do not have any continuity between the ground screw and the strap on a IG receptacle.

Mustang

Do you mind if I ask where the IG originates from?

Bob

Mustang, you are correct about the 2 ground conductors. The IG ground connects to the ground terminal on the rect. The egc connects to the box. Like kentvw said there is no continuity between yoke/strap and rect ground terminal. Do not insulate the yoke from your metal box. A true IG rect already isolates the 2 grounds.

Al

Hi,
Thanks for the replies. I thought that an IG recept came with an insulating spacer attached to each screw..

The IG circuit originates from a IG terminal that is bonded to the neutral at the service Main OCPD..

I appreciate the professional replies.

Sincerely

Mustang

Great, I only asked because it sounded like you where unfamiliar with IGs and many people think think an IG must run to a separate ground rod that is isolated from the buildings grounding electrode system.

Do not be offended, being unfamiliar with something has nothing to do with your abilities.

I am very unfamiliar with hazardous locations, but IGs I work with all the time.

Bob

Hi,
No offense taken. I have been in the trade 28 years and most of my experience is heavy industrial working around gas turbines and fossil fuel plants.

I am pretty good across the board but I do know everything. I do not mind asking a question if I do not know or if I am not sure.

I used to do a lot of commercial work but it has been a long time.

The electrical trade is about the broadest field there is.

I appreciate the comments and the way they are worded...i have been on jobs where if you did not know how to bend a 4 point saddle or a rolling offset you were considered a romex ranger...i can hold my own in both arenas pretty well. I have run a lot of pipe and i have jerked a lot of romex too!

The guy who claims to know it all is the guy to watch out for!

One thing for sure...you can always count on the expertise, knowledge and experience that is demonstrated on a daily basis on this forum..

I use the forum all the time to verify drawings, field conditions, or when i am planning a job or if i am just stumped..

You never know what is going to come up!

thanks again,

Mustang

I saw that style of isolation many years ago. More common, I think, is a yoke isolated from the receptacle.

so now an isolated ground type recept. has no continuity between the yolk and the IGC?

thats interesting..i will have to take a look at one of them.

it only makes sense since the device is isolating the ground from the other grounded components.

they both have the same potential though since they are bonded at the Main OCPD.

i have seen so-called IG systems that were not connected correctly.

how do you tell if there is another connection to the IG ckt?

are the benefits of an IG to reduce the interference to electronic equipment?

they seem to be called for in commercial and medical facilities.

does the code require an IG recept or ckt anywhere?

thanks for the comments

regards

mustang

Isolated Ground receptacles are not required by code. They are only required by design.
In my opinion, not too helpful.

i would have to agree that only under the most critical system would an IG system prove very beneficial..just imagine how many millions of computers and other electronic equipment is connected to the egc or none at all!

i would venture to say that there is a large percentage of homes in america that are running off a ungrounded system..

the added expense on a large job could add a considerable amount to the total installed price..

go figure..

mustang

IBM figured out many years ago that IG was mostly a waste of money and stopped recomending them. Unfortunately a lot of "experts" never got the word and I still hear people talking about how computers should have IG.
If you want IG in your house, just pull a dedicated Romex and use a plastic box ;-)