Instructions to electrician about dedicated line

If you are starting from scratch, install a 100 amp sub-panel off of the main breaker box. You can then run as many 15 or 20 amp circuits as is necessary. I'd use 10 gauge for all the runs regardless of the amperage rating of the breaker. If possible, twisted pairs would offer additional noise cancelling and rfi protection. Stick with 15 amp breakers for line level components, digital components, etc... The only ones that would ever benefit from a 20 amp breaker would be a big amp that is being pushed hard. Using this approach, you could literally have four 15 amp lines and two 20 amp lines at your disposal. All of this on dedicated lines. Make sure that each outlet is wired with its' own hot and neutral with each sharing a common ground amongst them. Some electricians will run dedicated hots and share neutrals. Sean
>

Macdonj, thanks for clarifying why i stated what i did. In that respect, you were right on the money. However, i would like to add that i don't personally feel that 10 gauge is sufficient for 30 amp service. Regardless of what most "professionals" will tell you, 10 gauge will produce a very noticeable voltage drop under a 30 amp load if it is anything more than a few feet long. I have measured sizable voltage drops using 8 gauge at lengths of under 20 feet while trying to pull 30 - 35 amps through it. As such, i would consider 10 gauge "adequate" for a 20 amp load using the normal length runs that one might find in a house. 12 gauge should be considered minimum for a 15 amp circuit. That is, if one is looking to reduce series resistance / voltage sag to a minimum.

As i've mentioned before, i'm simply sharing / passing on my personal point of view based on the experiences that i've had. As such, my comments are worth just slightly less than what you paid for them : ) Sean
>

Bear: While i can understand your thoughts about using one BIG isolation transformer to feed the A/V breaker box for sake of simplicity, what are your thoughts on using multiple smaller ( 15 - 20 amps each ) yet identical transformers wired in parallel ? Sean
>

I'll have to get back to you later tonight. Running late today : ( Sean
>

Bear, the system that i was thinking of would make use of multiple high current isolation transformers all wired in parallel. These would be used for one 120 volt feed into a secondary breaker box. This box would be used strictly for A/V gear and would have a dedicated ground.

To achieve this, you would have a parallel feed coming from the mains of the houses' primary breaker box feeding the isolation transformers. In order to protect the transformers should a winding(s) short out, fuses would be installed on both the hot and neutral legs between the transformers and the mains. The parallel wired transformers would then feed the input of the A/V breaker box.

In effect, every circuit connected to this box would be filtered and isolated from the rest of the house and whatever noise was coming in via the outside lines. Not only would you have dedicated lines, those lines would all be filtered. One could then use smaller isolation transformers at the component feedpoint as needed. My primary thoughts are that one would want to use such an approach for digital gear. While this is not so much to further filter what is going into the digital components ( although it would do that), i was thinking more along the lines of keeping the hash and trash that such gear generates from being pumped back into the line and other components.

The total output of the parallel wired transformers would be rated for a higher level than what the secondary breaker box was rated for. This would insure that the transformers could not be damaged due to pulling on them too hard. If such a situation started to develop, the main breaker on the A/V box would trip long before the transformers could come close to saturation. At the same time, running more isolation transformers than needed would also guarantee a measurable amount of headroom so that core saturation would never take place. This would keep the power cleaner with less distortion than what other current limited filters might introduce.

Does this sound like a plan ? Any thoughts / suggestions ? Keep in mind that i've partially based this on the fact that i already have several "beefy" identical isolation transformers. I have not ruled out going to one "huge" transformer as that would surely be far simpler to install. At this point in time though, i've not run across anything that was reasonably priced although i have been looking. Sean
>

I'm not claiming that isolation transformers are better or equivalent to power regeneration. There is NO substitute for power regeneration. Regenerators start from scratch and provide the best that they can give you whereas isolation transformers are simply trying to separate the good from most of the bad. With isolation transformers, you can still end up with a high level of distortion if the sine wave is not "clean" to begin with. TRUE "power regeneration" corrects this problem but is EXTREMELY inefficient ( high levels of thermal losses / heat build-up ). This is not to say that i think that the PS is the best that one can do in terms of having "clean AC", but it is probably the most commonly used amongst audiophiles.

Having said all of that, i do think that isolation transformers have their place. So long as you never come close to saturating the transformer, i think that they are less detrimental to AC than most PLC's and many times, do a better job of getting rid of noise. There are a few "good" PLC's that simply make use of multiple smaller isolation transformers with additional circuitry supplementing the job that the transformer is already doing. Obviously, a smaller transformer is suitable for line level components and / or sources, but you would not want to run a power amp through one. Personally, i would not want to run a power amp through a smaller PS Power Plant either. If you had a very small amp or one that ran in Class B or was a "switcher" and had high efficiency speakers, i would not see a problem with doing so. Since most all of my speakers are low impedance and low efficiency and most of my amps are relatively inefficient high bias designs, that would not work for me.

If i had my "druther's", i'd "druther" have my own high current AC generator ( with a BIG muffler ) and a "kick ass" voltage regulator in the backyard OR be able to run off of a bank of batteries. Neither is practical for me though, although the generator might be more feasible depending on where i relocate to. I will probably leave an option in the wiring to either draw off of the AC line or be able to insert a generator into the path if / when i move.

Right now, i have enough transformer ( 170+ lbs worth ) to isolate at least 60 amps of current at 100% duty cycle and up to 80 amps for an extended period of time. I'm working on doubling that capacity. I'd like to have all of the "goodies" that i need to do this before i relocate. That way i can get everything wired in / laid out prior to moving in all of my "junk".

As i mentioned, this will feed a breaker box that will feed MULTIPLE systems, not just one. That is why i want such a high current capacity. While i will never have all of the systems "cranking" at one time or be able to pull that type of power at once, i am a firm believer in designing for "worst case scenario". My motto has always been "over-kill baby, over-kill". I'd rather "feast all the time" rather than "famine" just once : ) Sean
>