I had the following PM discussion with member Almarg. As you can see he -- as always -- was quite helpful! However, upon my suggestion to post our conversation for others to see and perhaps learn, Al readily concurred, but suggested for the questions that he couldn't address, he referred me to Jim [Jea48].
It should be noted that I drug my Atma-Sphere amp manufacture, Ralph Karsten into this conversation via email. As generous and helpful as he always is, he too helped a bunch. I haven't copied his single email because the below is complex enough, without adding more.
My hope is that where my assumptions are questionable or for my questions, others will respond.
Our new house's rafters are about 50% installed, so the other trades will be in soon. And I will have to soon inform our electrician of our needs. But I don't want to request something that isn't needed. More IMPORTANTLY, I don't want to MISS something that is NEEDED! So your help in checking this thread is greatly appreciated!
NOTE: I've listed our conversation as Audiogon would -- the most recent post last. So, the real important part for me, is getting answers to the set of questions I asked towards the bottom -- Today at 20:28!!
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mrmb (you)
January 27, 2018 23:49
Thanks Al! That's what I was seeking.
Speaking of electrical noise/hum, I just found a Martin
Logan article speaking about pre-wiring
https://www.martinlogan.com/learn/faq-prewiring-a-home-theater.php.).
It addresses one of my other concerns about inserting
multiple dedicated circuits in one room. They advise to connect all
outlets/circuits with the same ground wire. I've previously read that ALL audio
components should be connected together -- i.e., on the same dedicated circuit.
If one didn't tie 2-dedicated circuits together by using the same ground, I can
see why I've seen that advice.
Have a great remainder of the weekend AL. And thanks for
sharing your expertise on Audiogon and in this PM. It's appreciated!!
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almarg
January 28, 2018 13:37
Hi Mike,
Thanks for sending the link to the article, which I hadn't
seen before. A couple of comments on it:
1)As you appear to realize, the benefit of the single ground
wire approach they advise is that it would minimize or eliminate any
differences of potential (i.e., voltage) between the safety ground connections
of the outlets for the various dedicated lines, and hence any differences in
potential between the chassis of components that are interconnected in the same
system but are powered by separate dedicated lines. Which in turn will avoid
ground loop issues that might otherwise occur.
2)If the electrician indicates that such an approach would
be problematical, due to either practical considerations or code compliance
issues, using 3-conductor Romex (e.g., 12-2 with ground) for each of the
dedicated lines should come close to accomplishing the same thing. And could
very conceivably provide results that are just as good.
In 3-conductor Romex the safety ground wire is symmetrically
placed between the hot and neutral conductors. Therefore voltages that may be
induced into the safety ground conductor by the magnetic fields surrounding
each of the two current carrying conductors [current flow in a conductor
produces a magnetic field around that conductor] will tend to cancel, since the
fields produced by the two current carrying conductors are in opposite
directions.
For further explanation see pages 31 to 35 of the following
paper, which was written by a renowned authority on such matters:
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Best regards,
-- Al
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mrmb (you)
January 28, 2018 20:28
Hello Al,
RUN LENGTHS/BALANCING:
I did recently find elsewhere as you suggested, that using
12/3 was a prudent approach, but thanks for seconding that approach.
We talked about Martin Logan’s single ground wire
recommendation. And you mentioned that using 12/3 (verses 12/2) may well
compensate, if code prevents the implementation of ML’s plan. I suppose if code
allows the M/L single ground wire approach and then 12/3 is also used, that
would be icing on the cake!
Because it’s a breeze to do while the walls are open, I
believe I will put 2-20amp outlets in the most important room – the 2-channel
one (just in case)! Residing therein will be: 1) Atma-Sphere MA-1 monoblocks; a
Lampizator Golden Gate DAC and 2-Soundlab M1PX stats.
For now let’s ignore the Soundlabs, which will be about 7
feet from the rack and that wall’s outlets, and thus, probably on their own 15amp
circuit. Would you recommend that the Atma-Sphere amps be plugged into 1 of the
dedicated 20-amp outlets and the Lampizator plugged into the 2nd. 20-amp
circuit? Or would it be better to plug all 3-pieces into the same 20-amp
circuit (plugging the Lampizator into an additional receptacle on the same
circuit)?
Ancillary to the question of what component(s) should be
plugged in where: Would there be any sonic downside to installing a Wall-Switch
for the 2-Soundlab’s dedicated line (and its ganged outlet on the opposite side
of the room)?
That is, would a Wall Switch be some sort of sonic negative;
because it was a part of that circuit (sonically deducting a positive, or
adding a negative)? And referencing the Martin Logan’s single ground wire plan:
I’m unsure if we tied 3-dedicated circuits together (both 20-amp ones and the
15-amp Soundlab one) with a single ground, if a Switch would prevent that
process from being implemented? Or would a Switch somehow negatively affect the
“single ground logic”, or simple be too cumbersome to install?
Lastly, if code will allow M/L’s method of using a single
ground on all dedicated circuits for my room, it may be difficult to implement
because of the distance the Soundlab's (7-Feet) are from the front wall
outlets. Especially when considering that the Soundlab’s outlets will be
19-Feet from each other – on opposite sides of the room.
My concern may be unfounded, because being the neophyte that
I am; I can’t envision how to implement a single wire ground for 3-dedicated
outlets as far apart as mine will be. And overall, I wonder if would be good
enough (in audiophile terms) to simply install 3-dedicated circuits and not be
concerned with using the same ground for each? However this may be confounded
by the fact that folks have suggested that if multiple dedicated circuits are
used, one should make the wire length for each one as close to the same as
possible. Without rolling-up and storing several feet of cable (in the walls or
at the panel) for the circuits longer that the other’s, this would be all but impossible.
I apologize for my hyper-granularity or should I say my
“analness” regarding this wiring issue, but that’s sort of the definition of we
audiophiles isn’t it? At any rate, I appreciate your assistance in a topic that
I’m flying blind on! After we’re all said and done here, for others to gain
from your teaching, I would like to post our communications on Audiogon as long
as you’re amenable to same. That’s the beauty of forums, many sharing/learning
from ONE!!! But I digress…..
WIRE:
The plan is to specify Southwire’s Romex ® brand of Solid
Core (vs stranded) wire – is Southwire Solid Core also your recommendation? But
I’m confused about the type of Romex ® to use. I’ve seen various ones: with
“XHHW” recommended over “THHN”, but also “NM” recommended. What say you?
WIRE GAUGE, MULTIPLE OUTLETS:
Additionally, I've found a piece posted by MSB to be
informational. As you can see
(http://www.msbtechnology.com/faq/how-to-wire-your-house-for-good-power/) their
thesis is that gauge size is of utmost importance! I’ve found some disagreement
relative to whether 8 gauge wire can be installed in an outlet or not -- your
opinion? At any rate, can an electrician pull 8 gauge to the audio room and
terminate it in some sort of junction box and go from there to my audiophile
grade outlets? And then, is there any downside to ganging several outlets from
one dedicated circuit? In my home theater area, rather than multiple wall
outlets, I’ve found it more advantageous to use a power center such as the
Furman Elite-20 PF I’m presently using. It has a video and a sonic benefit,
plus I find DC Triggers to be useful. So, unless you believe ganged outlets are
better than a Furman (et al), I won’t have the electrician install anymore
outlets than I think will be needed when using a Power Center.
PANEL-TO-PANEL WIRE GAUGE AND CONNECTION METHODOLGY:
Should I recommend a specific wire gauge or type for the
electrician to use BETWEEN the main 200-amp panels and the sub-panel? Should I
ask the electrician to use a specific method to use to tie these panels
together? One forum poster advised: “running one large wire from the very top
position in the load center on the leg with the least number of
noise-generating devices to a sub-panel”. Would this be your method?
BREAKERS:
I also found the following discussion from PS Audio
(http://www.psaudio.com/ps_how/how-to-install-a-dedicated-ac-line/). It advised
that 20-amp breakers should be used “for even the lowest draw source equipment
feed”. I took that to mean that although the circuit may be less than 20-amps,
that a 20-amp breaker should be used. Is that what you would suggest?
LOAD CENTERS:
So, my present plan for the 2-channel room (mentioned
previously) is to install 2-200 amp panels and a 60-100 amp subpanel for the
3-A/V areas (to get it as close as possible to 2-channel audio room – is this
your preference?
Speaking of load centers, I’ve found several positive
mentions of Schneider’s Model: “Square D QO” Panels (the “QO” Model with copper
plated busing). Does QO Square D model work for you?
GROUND ROD:
I’ve read rather lengthy dissertations on this subject. Not
being interested in getting into the weeds here, is there a material, length
and methodology you would suggest using here?
SERVICE:
And lastly, should I even be concerned about the wire/cable
used for the service drop or service entrance? NOTE: Service will be buried.
IT’S ABOUT TIME….THE CONCLUSION:
Whew, I can’t tell you how much I appreciate you wading
through all and helping with all of this!! It’s all but impossible to find
folks educated in this subject such as Electrical Engineers and Electricians
who care about the details we audiophiles do! So, I consider you a wealth of
information on the subject form your previous responses to my questions but
more importantly, from the number of posts and volume of information that
you’ve posted on Audiogon and I’m sure elsewhere!!!
Be well and take care,
-Mike
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almarg
January 28, 2018 22:06
Hi Mike,
Thank you again for the nice words.
I should have been more explicit when I referred in the
previous communication to "3-conductor Romex (e.g., 12-2 with
ground)," and subsequently to "3-conductor Romex." My reference
to three conductors included the ground conductor, so I was referring to
"12-2 with ground" and not to 12-3. The additional "hot"
conductor in 12-3 would serve no purpose in this situation, and if that
conductor were used to carry a current the benefit of the symmetry I referred
to between the current conductors and the ground wire in 12-2 would likely be
negated.
My suggestion of 12-2 Romex as a potentially suitable
alternative to ML's suggested configuration was in contrast, for example, to
using conductors within metal conduit, which as explained in the reference I
cited would be much more conducive to ground loop issues. Especially when
multiple dedicated lines are used to power the components in a single system.
Regarding your first question, my guess is that it would be
best to put the amps and the DAC on separate circuits. I say that in part
because various comments I've seen Ralph provide over the years lead me to
believe that his designs are less susceptible to ground loop issues than most,
and consequently there is unlikely to be any downside from keeping the amps and
the DAC with its potentially noisy digital circuitry on separate dedicated
lines.
Regarding a wall switch for the power to the speakers, I
don't see that as being a negative in itself. However as you alluded to the
considerable distance between the various outlets does sound like implementing
the ML approach would be cumbersome at best. And perhaps more significantly the
considerable length of the ground connection between some of the outlets may
negate a lot of the benefit of that approach. So perhaps just using "12-2
with ground" Romex in the normal manner, for each of the dedicated lines,
would be simpler, more practical, and provide results which are just as good.
Regarding the suggestion of keeping the lengths of all of
the dedicated lines the same, which I too have seen stated a number of times
and which the ML writeup implied is desirable, FWIW I am not a believer in
that. In nearly all applications the different lines would be carrying very
different amounts of current, and correspondingly their conductors would be
surrounded by magnetic fields having very different strengths, resulting in
very different amounts of current being induced in the ground wire. Not to
mention that voltage drops in the hot and neutral conductors would be very
different. So I don't see why keeping all the lengths the same would provide
any benefit.
Regarding posting our communications in the forums, that
would be fine with me. If you were to do so, or at least start a thread with
some of your questions, chances are it would catch the eye of Jea48 (Jim), who
is by far the leading expert at Audiogon on electrician-type (as opposed to EE)
matters.
And for that matter, Jim would be the best person to address
your questions about NM-B vs. XHHW vs. THHN, use of 8 gauge wire (which I
suspect would be extremely difficult to work with, as well as probably being overkill),
and most or all of your subsequent questions.
Regarding the question about PS Audio's statement that
"we recommend you use a 20 amp breaker for even the lowest draw source
equipment feed," though, I can say with certainty that it would be both unsafe
and a code violation to use a 20 amp breaker on a circuit which "may be
less than 20-amps." In other words, if a 20 amp breaker is used the outlet
must be a 20 amp type and the wiring must be 12 gauge or heavier. What they no
doubt meant, as you probably realize, is that even if the equipment powered via
that line only draws a small fraction of 15 amps, they would still recommend a
breaker, outlet, and wiring rated for 20 amps. Which would have no downside,
and I suppose might provide at least a small benefit in some circumstances.
Best regards,
-- Al
