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In Reply to: I'm no expert but check out ... posted by bjh on March 31, 2004 at 15:29:14:
The Bryant info page discusses Isolated Ground receptacles, and has a diagram showing the layout. There is ONLY ONE GROUND for the outlet.
Follow Ups:
was because, as I said, I am not an expert. However, what I read was that isolated ground wiring is intended for installation of sensitive equipment where it is desirable to ground the equipment via a isolated ground, the benefit apparently being avoidance of greater noise that cound be encountered if the equipment were grounded to the (normal?) building ground. There are two diagrams in the article. The one with the orange colored receptacle demonstrates wiring for the isolated ground case. In that diagram there are four wires, black, white, green (building ground), and green/white (the isolated ground).That what I saw and that is the extent of my understanding. I would kindly recommend you solicit clarification from someone more knowledgable that I if you require further information.
Thanks much, but I don't need to consult with someone - you do. You misunderstood the diagrams you looked at. There are NOT four wires connected to the receptacle. There are only three - hot, neutral, and isolated ground. There is an important distinction you are missing. That distinction is absolutely critical to your safety.Please don't take offense at this, because I don't mean in in a pejorative sense; I'm genuinely trying to help - if you do not understand basic wiring diagrams you should not be attempting to change out electrical outlets yourself. The consequences of your lack of knowledge of basic electrical concepts can kill you or your loved ones.
Check the link below.
Sony SCD-777ES > > Silver Audio SB 4.0 > > AI M3A > > Silver Audio Hyacinth > > Odyssey Stratos > > Tice 416A Bi-wire > > MG 1.6QR
He's looking at a standard commercial installation wiring diagram with a standard commercial installation grounded metal gang box that contains an IG receptacle, and he's thinking that because he sees what appears to be two ground paths in the diagram (the gang box's ground and the IG) that they must both be connected to the IG receptacle's ground lug.At the very least this would defeat the whole point of an IG by connecting the ground noise he's trying to avoid right back into the circuit, and most likely introduce massive hum into the circuit due to the differing potentials between the gang-box ground and an IG wire that goes back to the building ground or other code-legal ground terminal. At worst a big enough potential between the bonded IG wire and the gang box ground could cause a grounding failure in the event of a ground fault or lightning strike.
Actually, no that is not what I was trying to accomplish at all.But first, the additional resource only reinforces my understanding of isolated groung - there are two paths back to the same earth ground - I never clamed that the isolated ground path (wire) terminated elsewhere.
Now onto what I was trying to accomplish, I was simply asking how does one wire a isolated ground receptacle into a box being feed by the standard 3 wire feed. The answer was precisely to defeat the isolated ground path (in the receptacle) by connecting it to the building ground - hence turning into into a regular (non-isolated ground) receptacle. That's it. Perhaps you might ask - well wasn't that obvious? The answer is, no it wasn't, and that's why I asked.
The next question is: why would you bother with an IG receptacle if you are going to defeat the IG?The whole IG concept was designed for commercial installations, and really doesn't have tremendous applicability to a residential installation.
HOWEVER - the benefits of an IG can be realized in a residential installation if you have a 3-wire "feed" as you call it to the gang box. If your 3-wire cable is a sheathed wire like a Romex-style NM or other cable where the ground wire is insulated, AND the cable is a home-run to the panel with the ground wire attached to the panel grounding strap, if you connect the insulated ground wire to the ground lug on the receptacle WITHOUT DEFEATING the receptacle's IG, then you have created a defacto IG, or at least as close as you need to get to IG in a residence. All of this is code legal.
If the ground wire is not insulated and is inside metal conduit or is bonded to metal gang boxes, then that ground also serves as the ground for every other receptacle in your house, and using that would mean that installing IG outlets is a waste of time and money. In this case the only way to get a close-to-IG would be to leave the receptacle's IG setup in place and home-run a separate, insulated ground wire TO THE GROUNDING STRAP IN THE PANEL.
"The next question is: why would you bother with an IG receptacle if you are going to defeat the IG?"How did I know you were going to ask that question? Basically I was out at my local Home Depot looking at receptacles. Hmmm no hospital grade receptacles but what's this thingy. Looks like high quality, hey contacts really grip the plugs, maybe I try this out. Lot cheaper than ordering Hubbell hospital grade from the audio DIY guys. Isolated ground? - no idea but I'll figure that out later.
Completely agree with your other points.
Again, sorry for the confusion, and I really appreciate you taking some pains to ensure I didn't fry myself or burn the house down.
Bernard
Take a look at my post about a tweaked Cooper AC outlet from Lowes. Even if you don't tweak it, I bet it would sound better than the Leviton.see link below:
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