Isolated Ground

[peter d]

What's the real story? Is IG really effective? We spend an awful lot of time installing IG circuits, but I often wonder what good they do.

Heck, I don't mind putting them in. The pay is the same. But having a "clean ground" for equipment to operate "correctly" makes little logical sense.

 

[drg]

If you don't have a isolated power supply then they don't really offer any benefit do they ??

I have been in the situation where IG recps. were spec'ed and there was no isolation transformer or supply but we just put them in as required, I always thought it was pointless but who do you argue with ?
Who Cares?
Are they doing what they were intended to do .......no.
Get er done.

 

[George Stolz]

Pete, click here for a gold mine.

 

[George Stolz]

Whoa! You stalking me?

 

[drg]

Stalkers post after the fact not before.

That link you gave was interesting,

I have seen IG receptacles put in for no rhyme of reason but so what , we just put them anyways , dumb but so what.

On the other side I have been involved in theatical stage work where they have all the bells and whistles , isolated transformers , all kinds of weird stuff and all circuits carried their own neutral also, nothing shared . no muti-wire branch circuits etc,

In theory all the pieces were there for a IG system , but I am just there on the installer end and it was impressive. Does it do what it claims ?? I really don't know that answer to that, all I know a lot of cash Is spent to hook this system up and maybe somebody who designs it knows more than the people here ........then again maybe they don't ...what say you on the subject??

 

[George Stolz]

Stalkers post after the fact not before.

That just makes you really good at it.

I was just joking by the comment, in case anybody is confused. John and I have made peace about our previous quarrels, and I didn't intend for him to get in trouble for my mediocre sense of humor.

Sorry for any misunderstandings that may have resulted.

 

[emahler]

nah, after about 6 months past the initial installation, someone will corrupt them anyway.

We do a lot of work for one of the big wholesale food stores. Before we started with them, one of the stores had indicator lights mounted on unistrut that went from the ceiling trusses (metal) to the register counters. They used MC cable and metal boxes. Well, about 1/2 of the lights were fed from the 'isolated ground' source, and the other 1/2 from the dirty power source. Corrupted the entire Isolated Ground system.

But you know what, there were no problems and no noticable difference with the operation of the cash registers (IBM POS)

Basically useless these days.

 

[drg]

Its to late now , I have had a rock thrown though my bedroom window since that claim and the only thing that saved me from flying glass chards was a piece of cardboard that I keep on my windows to keep the sunlight out.

 

[George Stolz]

what say you on the subject??

As a commercial apprentice, I say "Yes sir, what height would you like those at?"

I feel they do nothing, but if they are spec'd who are we to argue?

Edit: You were one minute early again, I'm rolling on the floor laughing now.

 

[LarryFine]

I've always been under the inpression that the IG is intended to minimize the effects that ground faults and other unintended EGC currents from other equipment have on the sensitive electronics.

Poor conduit/EGC conductivity and the like, especially during a high-current ground fault, can raise the voltage between chassis and signal grounds on normally-grounded equipment.

 

[haskindm]

The main benefit of an IG circuit is that you are allowed to pass the ground through any sub-panels and take it all the way back to the main panel. If there are no sub-panels or the sub-panels are installed correctly (grounds and neutrals seperated ptperly) there is little or no benefit derived from an IG Circuit.

 

[iwire]

nah, after about 6 months past the initial installation, someone will corrupt them anyway.

Lucky if it's not corrupt before you get home the day you power them up.

It is so easily corrupted by anyone.

 

[peter d]

Your replies pretty much confirm what I allready suspected. IG is pretty much unnecessary.

You should have seen the look on Iwire's face when I used some isolated ground receptacles to hook up temp to plug our lifts in the other day. Priceless...

 

[iwire]

You should have seen the look on Iwire's face when I used some isolated ground receptacles to hook up temp to plug our lifts in the other day. Priceless...

Be nice.....I can post a picture of your IG temps.

I think 'mounting' the box to the compactor/dumpster corrupted the isolation.

 

[infinity]

It seems that 10 years ago IG circuiting was de rigueur, but no longer. I haven't seen an IG designed system in years.