Isolated ground circuit

I want to run an isolated ground from a sub panel (which does not have the ground and neutral bonded) to a receptacle for my computer. What is the proper method. I won't be using a metal box, just a plastic old work box. I have a book (Black and Decker Complete Guide to Home Wiring printed in 2001) which shows 14/3 run to the circuit. It has the black to hot white to neutral red to ground and marked as ground with green tape which hooks to the ground bar in the panel where it is also marked with green tape. It shows the bare ground (mind you this is just an illustration) just floating away from the panel connected to the ground sign. The other bare ground is just coiled up in the box. This seems strange to me and I haven't found anything straight forward to show me exactly what to do. In the 2005 handbook I have it does show an insulated conductor that goes to the receptacle and the panel for a ground, but they are also using a metal box and say that the metal box and the emt or raceway must be grounded too. If I recall all metal boxes and such must be grounded so it doesn't help me with the plastic box.
Hope I made it clear enough. TIA Shane
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Technically, you're not allowed to remark a 12 gauge conductor as you describe. Why not use a metal box and MC cable which has an insulated ground conductor. In your particular case, I don't know why 2 conductor romex w/ground wouldn't be fine. The bare ground is isolated inside the cable and insulated by the plastic box

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I figured just plain old 12/2 on it's own circuit should suffice, but I was stumped when I saw in that book that they used 14/3 and had the red marked as ground and the bare ground coiled up in the plastic box. I was trying to figure out if they were using the coiled ground to act as sort of an antennae to attract any stray RF ore something to that effect. With that being said, is it still a true isolated ground then if I just use 12/2 w/gnd in a plastic box hooked to the ground bar of the subpanel? Will the bare copper entering the subpanel after the sheathing is removed make it act like an antennae?
Thanks Shane
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Once you're inside the sub panel, the box is part of the grounding system, so it shouldn't matter. If it matters to you, insulate it inside the sub panel

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You watch, just as soon as you finish this project, your mother board will blow for some strange reason. I've got a pile of PC's here, all connected to standard grounded outlets, but protected by separate UPS devices. Never had a problem

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On Mon, 30 Jul 2007 19:24:25 -0400, "gorehound"

IBM wrote off IG circuits in the 80s as useless snake oil. They removed the requirement from all of their equipment ... all of it. It will certainly be a waste of money on a residential PC
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Total waste of time and effort. Isolated grounds *may* be needed for sensitive equipment such as certain mainframe computers, or medical equipment. There is absolutely *no* benefit to you in having an isolated ground for a home PC.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Indeed. Besides, there's nothing "isolated" about an insulated wire connected to the ground bus in a subpanel, neutral-bonded or otherwise. What exactly would it be isolated from then? The box has to be grounded in any event. Through yet another wire?
True isolated grounding systems are totally separate from regular grounding.
Except in industrial/medical circumstances, you'll probably be making it _more_ "dangerous" (to whatever the concern is) than less.
You need nothing more than a regular grounding system and appropriate surge protection.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
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On Tue, 31 Jul 2007 20:11:47 -0000, snipped-for-privacy@nortelnetworks.com (Chris Lewis) wrote:

The theory of IG is you have a star grounded system with everything radiating from the ground bus in the main panel where the ground electrode connects. You are supposed to pass through all subpanels without connecting to their ground bus. The reality is, modern line driver/receiver practices and internal noise rejection make it unneccessary. I think it all came about during the learning curve of silicon IC technology.
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wrote:

Thanks everyone for the help, and thank you gfretwell for the explaination for the isolated ground. I just ran a dedicated circuit from the subpanel for the computer.
Thanks, Shane
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