Electrician Coming Over What to Do?

Stehno makes some very excellent points. However, i personally would not spend the money on the JPS cabling. While i do believe that AC cabling and geometry of said cabling can make a difference, i just don't think that it is an $18 per foot difference. I am currently looking for cabling that will perform optimally and not cost a fortune i.e. "the most bang for the buck". Along the same lines, i would look at the availability of various outlets. If you do go the dedicated ground routine, you may have to buy specialty outlets that float the ground connection separately from the conduit.

Obviously, the AC wiring and outlets are a matter of personal preferences / budget, so do what you think is best suited for your situation. I would stick with at least 10 gauge wire and nothing lighter though. You could use either 15 or 20 amp breakers using this approach, sizing them according to draw. This also takes into account safety precautions in terms of having a breaker so big that even "flaming" components would not trip it. Should you increase the load on a circuit that you originally install a 15 amp breaker on, you can always replace the breaker with a 20 amp and never be concerned about the wiring.

I would also add that you should remind the electrician that all of the circuits need to come off the same leg / phase of the circuit. In order to even out the load in the house, he may have to make some changes in your main breaker box.

Other than that, my experience is that dedicated lines do nothing to fight the noise that is already present coming in from the pole transformer. Such a set-up does offer an increased amount of isolation from other circuits within the building though. This can be further increased by running isolated grounds.

If you do go the isolated ground routine, you CAN NOT connect anything else to your audio system that is not plugged into your "standard" non-dedicated circuitry other than battery powered devices. Doing so would tie the two different grounds together, which could result in a lot of noise and what is even more important, a safety issue. As such, have all the lines put in now that you think you will ever need in the future.

I have never checked into "whole house surge supression", so i can't comment on that aspect of your question. I do not think it is a "bad idea", only that i'm sure that there are several different ways and products to achieve this. If you are interested in such an item, i would start researching it as soon as possible. The electrician may not be able to install such a device now, but he can do all of the necessary prep so that he would not have to "undo" all that he dows now to install such a device at a later date. Sean
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Glen: As you know, i'm not an electrician, nor do i play one on TV or Audiogon : )

I guess i should have clarified that each circuit should have its' own hot, neutral and ground to minimize series resistance and negate any possibility of wire saturation. Sharing neutrals would increase cross-talk between circuits and could result in the situation that you described. This would also cut down on the noise isolation characteristics that we are trying to achieve by going to dedicated / isolated lines. I guess that i took for granted that one would know enough to do make sure that this was done, but i guess i took too much for granted. Thank you for bringing this up.

As to your comments about common neutrals and electrical fires, i just read an article about this. It seems that the massive influx of switching power supplies, digital gear, etc... is playing major havoc with house wiring and the power companies nowadays. I am thinking that there will have to be some major changes to the various local and national power and wiring codes in the near future to try and alleviate these and other potential problems. Have you seen / read / experienced any problems with this type of situation ?

Natalie / Glen: I think that your experiences are more the exception than the norm when it comes to dedicated lines and noise reduction. While i do agree that dedicated lines will lower the noise being fed into the system, i still think / have experienced major amounts of noise being pumped in on dedicated lines. If one is in a heavily populated area and / or has any type of industry nearby, there is nothing short of heavy filtering that will remove / negate the noise that is coming down the line. With that in mind, I have to ask: "what makes you think that running separate breakers / lines from the other circuits in your house would remove all of the other outside interference that is already present on the mains" ?

No matter how many lines you have hooked up or parallel paths the noise can take, it will go wherever the current is drawn. If your system is drawing current, i'll bet that there is noise on the line feeding it. That is, unless you are operating from a bank of batteries and a high powered inverter ( i need not mention names here : )

As mentioned in another current AC noise thread here on Agon, one could / should check into just how "quiet" their AC is by using a "Noise Sniffer". I have actually witnessed a name brand "Power Line Conditioner" / "Noise Filter" introduce MORE noise into the system than if a device was plugged directly into the wall. The "Noise Sniffer" can actually help you to track down sources of noise within your own house. It helped me to identify what was "sneaking through" an otherwise "excellent" PLC.

Drubin: My comments are based on the fact that many "isolated grounds" are installed in areas far away from where the ground that is connected to the main breaker box is installed. As such, there is the potential for a vast difference in ground conductivity to exist. In such a case, the difference in conductivity will result in a voltage potential being placed on the chassis of anything that is connected to either ground IF there is a connection made between the two grounds. These voltages can be quite high, resulting in noise being generated, ground loops, hum, etc... Under specific conditions, such a combo could become lethal. THAT is why it is "illegal" in most places to have multiple grounds.

To reduce the potential for such a situation to exist AND keep your dedicated / isolated ground, one should install a ground rod as close as possible to where the mains are grounded. While this may raise series resistance to ground a little bit in terms of the distance that it must travel from your audio system, one can get around this by running a heavier gauge wire. What this accomplishes is that both grounds ( the mains and the dedicated outlets ) share common ground conductivity. This minimizes the difference in ground potential between the two, yet allows you to keep them separate. If a building inspector "wanders by", he would probably throw a fit and tell you that the two grounds need to be tied together, which really isn't a big deal either. Since they would be joined right at the point of Earth entry, cross-talk from the mains and dedicated lines should be shunted anyhow. It is only when circuits share a common ground that is long in length or resistive before being shunted to Earth that noise becomes a problem in most cases.

While i'm on the subject of grounding, i would suggest that once everything is installed and verified to be working properly, i would take steps to waterproof / insulate your ground rod / wire termination. Since this is going to take place at ground level and probably outdoors, it will be exposed to all of the elements i.e. rain, dew, possibly snow, etc... As such, a corroded ground is just as bad as no ground in my book. Just remember that whatever you use to seal up this connection should be easily removable as it might have to be taken off for system maintenance, etc...

Also, you might have gathered that one should install good sized conduit if doing this from scratch. This would allow you to pull as much wire as needed now and leave room to move in terms of "wiring upgrades" or additional circuits in the future. Better and cheaper to do it "right" the first time than to have regrets later.

If i have made any mistakes in this, PLEASE take the time to correct me. As i stated, i'm not an electrician and as we all know, AC can be extremely dangerous. Not only do i want to learn what will work "best", i want it to be done in what is the safest and ( hopefully ) most legal manner possible. Hope this clarifies a few things and helps some of you out. Sean
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Glen / Drubin: I ran into a situation where a gentleman had two separate grounds that were no more than about 10 feet apart from each other. The way that things were set up electrically, he had items from both grounds tied into the same system. He had mentioned to me that he was getting "whacked" when touching specific items within the system. I stopped by and took a look at what was going on. I was able to measure 40 volts on the chassis of some of his components due to the ground situation.

Once we tied the two ground rods together, the voltage dropped down to zero as we had minimized the differences in potential between the two grounds. The reason why he was only getting "whacked" on specific components had to do with how they were wired internally or the fact that he had a couple of pieces that were not oriented in the outlet for the proper AC polarity. Once we had gotten all of this straightened out, his components were no longer "hot" and the noise floor had dropped quite a bit.

I have run into other situations that were of similar nature, so i know this to be a somewhat "normal" situation. That is why i suggested keeping the ground rods as close together as is possible. So long as they are within a foot or so, i don't see a problem developing. If it does, one can simply strap the two together and be done with it. Sean
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Glen: a TRUE "isolated" ground is just that, "isolated" from all other grounds. Having a ground path that runs directly back to the earth ground from the audio circuitry without tying into any other circuits would be called a "dedicated" ground. Obviously, this wording could still get us into trouble and keep us confused. While all of this boils down to a matter of wording and semantics, i think that we are standing on the same basic "ground" and have "common" thoughts about the subject : ) Sean
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