Isolated Grounding for Computer Panels

[soldier_sss]

Why is isolated earthing conductor recommended for computer panels ?

 

[Smart $]

Why is isolated earthing conductor recommended for computer panels ?

Mostly it is a carryover from a time when power supplies internal to computers were believed to and may have caused RFI. Shielding of those power supplies were connected to equipment ground and RFI impressed upon the shield made the grounding conductors act as antennae. Running an isolated grounding conductor inside of metal raceway provided another "layer" of shielding.

Advances in power supply technology has rendered isolated grounding an unnecessary expense, if not unnecessary period... but there are those that still believe....

 

[iwire]

Not saying smarts answer is not correct but I had always heard it was important for data equipment that carried the ground between equipment on the data cables, such as RS-232 type, IBM Cabling or coax type connections.

It was my understanding the isolated ground was used to try to eliminate circulating AC currents on these type of data lines.

Meaning with Ethernet connections the IGs are useless.

 

[brian john]

N

It was my understanding the isolated ground was used to try to eliminate circulating AC currents on these type of data lines.

s.

We saw this in systems with coax and in the cases we worked on was eliminated by correcting wiring errors. The engineers still insisted on IG?s and what to heck, the customer was paying for it!

 

[garbo]

Isolated Grounding for Computer Panels

I have not installed an Isolated ground for anything in over 15 years. The very large Hospital where I work has over 10,000 computers spread out at 4 main campus and over 20 remote sites. Would not even try to image how hard it would be to pull a ground wire from the 12th floor down to 3 floors below the first floor to the 12" water main. They were big in the late 70's and early 80's. If the computer that a panel feeds is important [ya everybody tells us that their computer is critical ] it should be backed up by a large ups feeding the panel, a good surge protector then a ups for each computer. We have at least 40 isolating receptacles, both staight blade along with twist locks collecting dust in our electric shop storage room. tom grabowski

 

[brian john]

I have not installed an Isolated ground for anything in over 15 years. The very large Hospital where I work has over 10,000 computers spread out at 4 main campus and over 20 remote sites. Would not even try to image how hard it would be to pull a ground wire from the 12th floor down to 3 floors below the first floor to the 12" water main.

No problem there, because that is not how an IG is installed.

The IG (if you decide to utilize it) should originate at the SDS that feeds the distribution panel.

They were big in the late 70's and early 80's. If the computer that a panel feeds is important [ya everybody tells us that their computer is critical ] it should be backed up by a large ups feeding the panel, a good surge protector then a ups for each computer. We have at least 40 isolating receptacles, both staight blade along with twist locks collecting dust in our electric shop storage room. tom grabowski

In a properly maintained UPS distribution a downstream UPS seems a waste of money based on the size of the systems you are discussing.

 

[ron]

Hopefully isolated grounding and oversized neutrals will be a thing of the past sooner than later when old boiler plate specs are updated for computer rooms.

 

[ohmhead]

Well i know everyone says the old IG is not needed so i wonder why in a Boardway Theater today .

The engineers use 200 % neutrals on any sound power and IG ground in all feeders raceways and we run it the IG from ground bar main service room to swbd or panel location remote .

But it gets better transformers in the building must have a loop in the primary feeder and a loop in the secondary feeder meaning the flex has a 4 foot extra loop a circle entering the transformer this is for sound power only .

IG ground and equipment ground double neutrals and next if the transformer is hung from ceiling we must have it installed on a concrete platform and that platform is concrete on a steel frame which is hung from the ceiling with isolator springs to ceiling and on transformer .


They say this eliminates audio issues .

This is also done on dimmer system power go figure is this really helping the audio .

 

[brian john]

Because they know nothing about what they are doing. They had a problem in the past and tried voodoo electrical it worked and now it is spec. More than likely the issue was corrected in the past they overlooked the real issue as they tried all sorts of strange configuration installs.

 

[Tetra]

I actually installed IG's in a fine arts center a couple years ago, and I asked my foreman what IG's were for and what they did, the way he explained it to me was IG's were used on sensitive equipment to prevent "noise" or harmonics from creeping back to the computers (or whatever equipment the IG is for). So for this kind of equipment i always though of IG's as more or a 'drain' or a 'shield' then a proper ground.

Being a fine arts center there were a ridiculous amount of IG's so it seems to me like IG's aren't being phased out as Ron was hoping a few posts back.

 

[iwire]

I asked my foreman what IG's were for and what they did, the way he explained it to me was IG's were used on sensitive equipment to prevent "noise" or harmonics from creeping back to the computers

In my honest opinion I don't think your foreman knew the answer and was just reaching for anything.

IGs do nothing about the harmonic currents that the electronic equipment produce.

And 'noise' well, that sounds pretty vague don't you think?

 

[Tetra]

In my honest opinion I don't think your foreman knew the answer and was just reaching for anything.

IGs do nothing about the harmonic currents that the electronic equipment produce.

And 'noise' well, that sounds pretty vague don't you think?

Could be, decided to read up on IG's after I posted this to see if there was any actual validity to what he told me, what I've found is some people don't believe there is any real benefit to IG's and others are devote believers that IG's are essential. Anyhow the purpose of IG's appear to be the same in all the places I've read about them. And I did fail to see where IG's offer protection from harmonic interference but I actually did happen to come across the term 'noise' in several places.

I actually came across a good discussion on IG's on Mike Holts site:

http://www.mikeholt.com/technical.p...itle=Isolated Ground - Computer Power (8-3-99)

A discussion on the installation of IG's rather then their function but a few responses (particularly #6) seems to be the most common explanation I've come across

 

[brian john]

I actually installed IG's in a fine arts center a couple years ago, and I asked my foreman what IG's were for and what they did, the way he explained it to me was IG's were used on sensitive equipment to prevent "noise" or harmonics from creeping back to the computers (or whatever equipment the IG is for). So for this kind of equipment i always though of IG's as more or a 'drain' or a 'shield' then a proper ground.

That is the typical explanation for those that do not know why they are installing IG's

Being a fine arts center there were a ridiculous amount of IG's so it seems to me like IG's aren't being phased out as Ron was hoping a few posts back.

Hey there is money to be made. If they are willing to pay and won?t listen.

 

[the blur]

Last call I had for an IG problem.... the outlets wern't grounded. hmmm, pull the panel cover, and the grounds were dangling. because the subpanel didn't have a ground bar. all commerical EMT, no grounds anywhere, except the conduit.

I was going to screw a ground lug to the panel, but the plant mechanic bonded them to the neutral bar..................................................

never heard another thing about it.

 

[brian john]

I was going to screw a ground lug to the panel, but the plant mechanic bonded them to the neutral bar..................................................

In a sub panel?

 

[infinity]

Hopefully isolated grounding and oversized neutrals will be a thing of the past sooner than later when old boiler plate specs are updated for computer rooms.

Not sure that they'll ever die. Recently we did a Broadway theater and they still required IG's for all audio and video power. They even went as far as to put every audio and video receptacle on the same phase in the panel.

 

[ACE1970]

they do this to make sure they have clean power you are running 60hz and creating a frequency change every second which in terms causes audio and visual equipment to become interrupted and that creates distrubances in video and audio recordings remember that most electronics run on DC and have rectifiers that do that change for them. And a larger grounding system in terms make those changes slightly faster with less interferance they also have so called noise filters just depends on the type of system.

 

[brian john]

they do this to make sure they have clean power you are running 60hz and creating a frequency change every second which in terms causes audio and visual equipment to become interrupted and that creates distrubances in video and audio recordings remember that most electronics run on DC and have rectifiers that do that change for them. And a larger grounding system in terms make those changes slightly faster with less interferance they also have so called noise filters just depends on the type of system.

NOPE........or baloney

 

[ACE1970]

What where you answering to if you are just a helper .. no degree or license

 

[Dg01501]

i feel like you can only get a good isolated ground from an ig transformer....somewhere along the line they all tie back together at the main or at the earth.