(Mods, if this isn't the appropriate forum for questions about AC power, feel free to move)
Simple question (I hope)...
If I only have a single outlet on its own dedicated AC circuit, are the advantages of isolated ground pointless and/or redundant?
If its a commercial bldg using conduit run three wires back to panel, then use a isolated ground recepticle..
This will be the best you can do..
You don't want to share a ground with other equipment...
The long answer:
As tINY already said, "You should wire the Hot, neutral, and ground straight back to the breaker panel - then you have an isolated ground."
An isolated ground receptacle removes the ground path from the conduit. This is helpful when you have multiple conduits going back to the mains panel together (tied) and insures that the summing node is at the panel.
It is not that you don't want to share a ground with other equipment but you don't want to share a line with vacuum cleaners and HVAC blower motors, etc.
Bob, if you are in a 'home' situation, you should be fine (no conduit). But do check your wiring in the panel to insure it follows the above advice (quote from tINY). A good ground stake at the service entrance is required for low noise and safety.
The short answer: In your situation it is usually not necessary.
You should wire the Hot, neutral, and ground straight back to the breaker panel - then you have an isolated ground.
If you have a single outlet on a breaker and it's not wired this way, find a better electrician.
The ground in the breaker pannel is connected to every other ground circut connected to that pannel,
maybe I'm wrong but where I'm at we have a dedicated 6' long copper rod that is pounded into the floor of the equiptment room, all the outboard gear and consoles ground is connected to that as well as some plugs on the live floor.
I think thats an isolated ground,
but connected to the plannel with all the other grounds
I'm not so sure about that.
A dedicated feed for sure
Yes, it is connected to all the other grounds at the panel.
The large gauge wire to the ground rod insures a low impedance line directly to earth ground (reference). The point where that large gauge wire connects in the panel becomes a 'summing node'.
Actually the words 'isolated ground' are an oxymoron. Ground is anything but isolated. Yes, separate runs to the summing node are important and grounds must not be cross-connected creating loops.
What we are needing is ZERO-LOOP-AREA in our AC for audio wiring. Loop Area is 90% the cause of noise problems in audio systems. The other 10% being line induced noise such as hash from roof-top compressors down the street and refrigerators, HVAC systems, or vacuum cleaners in the same building. This type of noise is filtered using a filtered isolation transformer for the audio system lines. I also highly recommend the use of Surge-X, which not only includes surge protection but also hash filtering.