Dedicated lines - 1) use isolated grounds or not? 2) subpanel wiring

lem321

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Feb 7, 2014
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I've perused the forum for information on dedicated lines for my audio system. Some recommend using an isolated ground (IG) in their lines, while others have not. While I'm in the process of putting together a shopping list of parts, I must also choose some audiophile duplex receptacles. Most of the well-known ones mentioned here (e.g. Oyaide, Furutech) do not seem to have a model with an IG facility. Does this make an IG somewhat of a moot point?

Secondly, having my electrician also add a subpanel which will be about 25-30 ft. from the main panel. What do you recommend I use to connect the main to sub panel? 3 gauge is commonly mentioned. Should this be run in an aluminum, steel or other conduit (impractical to run it inside the walls)?

Thanks in advance for any advice you may offer.
 

DaveyF

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Jul 31, 2010
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I went through a complete dedicated line install just recently. In my case, we rewired the cabling from the outside transformer with 400 amp wiring( a major pain in the a..., as we had to pull up my lengthy driveway and a good part of the street...don't ask the cost!!:( ) ( replacing all of the connections at the transformer) and then to new 200 amp panel with a 10/3 dedicated single line to the room. ( No breaks in the line from the panel and minimal length to the room). I installed an IG 20 amp connector at the wall...IG is a good idea if you have dual grounding rods as I do. ( The code in S.Calif now requires a dual post into the earth at appx. 6' apart).
 

Ron Resnick

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I am engaged in the same learning and decision process as you are. I selected Furutech receptacles even though Furutech does not make an isolated ground model. The Furutech receptacles can be mounted in boxes using rubber gaskets to achieve an isolated ground.

To try to help with your next two likely questions I selected JPS in-wall wire to go from the panel to the outlets.

Between the gold and the rhodium Furutech receptacles I selected the gold (based solely on the consensus view that the gold receptacles are a bit softer and less detailed than the rhodium receptacles). However, I likely will switch that part of the order to the new NCF receptacles, based on the enthusiastic reports on WBF about the new NCF receptacles.

PS: I just cannot get excited about AC wire and receptacles, so I am happy to defer to audiophiles with much more experience in this area than I have.
 
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Scott W

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I personally am of the kiss(keep it simple simon/stupid) philosophy and ran one run of 10/2 WG Romex, one receptacle and one breaker for each of my 11 dedicated circuits(every circuit) in my stereo room. In my old house I ran both 10/2 WG and 10 gauge, military spec, Teflon coated, silver cladded copper wire. When I compared the two I actually preferred the romex. For sub panels I recommend either the Square D QO(not the HOM) or the Cutler Hammer CH(not BR). The design of these panels and breakers are better than any other residential design out there. The problem I have found with IG is if it is done 100% correct it can be good, but not always. And most of the time it is not done correctly:(. Don't ask me what correctly is as I have an electrician that does dedicated circuits for my customers and I always tell him to skip IG.
 

DaveC

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Nov 16, 2014
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The Furutech NCF receptacles are head and shoulders above the competition. The wall plate and cover are actually worthwhile too. (I can get you a good deal on these parts and will burn them in for free ;))

One of the primary goals should be to reduce resistance between grounds, so if you run multiple lines put the receptacles in the same ganged metal box or if using power distributors for each line then tie their grounds together using a heavy gauge ground cable. ALL of the system's ground connections should be connected together as close to the components as possible.

For wire I'd just go with 10g romex, or you can get THHN wire and run twisted pairs with a ground wire twisted the opposite direction around the pair. This is a better geometry, but more work and would need to be in conduit.
 

Speedskater

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Sep 30, 2010
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The Furutech NCF receptacles are head and shoulders above the competition. The wall plate and cover are actually worthwhile too. (I can get you a good deal on these parts and will burn them in for free ;))
Lets skip over this audiophile stuff and get on the the 'good engineering practice' information.

One of the primary goals should be to reduce resistance between grounds, so if you run multiple lines put the receptacles in the same ganged metal box or if using power distributors for each line then tie their grounds together using a heavy gauge ground cable. ALL of the system's ground connections should be connected together as close to the components as possible.

For wire I'd just go with 10g romex, or you can get THHN wire and run twisted pairs with a ground wire twisted the opposite direction around the pair. This is a better geometry, but more work and would need to be in conduit.
Now this is the good information, go with it.
 

Speedskater

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Sep 30, 2010
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Cleveland Ohio
My thoughts:
a] Isolated grounds are only for building that have metal conduit (flexible or rigid) or metal building framing.
b] Cables should be one or two AWG steps larger than required by NEC code. (14, 12, 10, 8)
Note that the largest size form most receptacles is 10 AWG. So a short pig-tail may be required.
c] Most music systems can operate on one 20 Amp circuit.
d] For very large systems use a 40 or 60 Amp run to a sub-panel near the music room.
e] Try to reduce the length of the runs from outlet box to outlet box.
f] Heed Dave C's note about Romex® or if required conduit.
 

lem321

Well-Known Member
Feb 7, 2014
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Thanks very much guys! That is all great information. It seems the consensus is that isolated grounds can be useful but not necessary and may even have some downsides if not implemented properly. As I'm planning to use some of the audiophile receptacles that don't have IG (e.g. Furutech), I will nix the idea of isolated grounds. BTW, my current set-up is actually dead quiet (from hum) using two non-dedicated lines in my audio/video room. I'm hopeful that the new dedicated lines will add additional improvement in sound quality.
Current system is all tube-based, ARC phono, preamp, monoblocks and CD player. Music is mostly vinyl with VPI, Koetsu, Lyra. Shunyata for power management.
 

Speedskater

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Sep 30, 2010
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Everything you need to know about AC power for audio/video installations and a whole lot more.

Middle Atlantic Products paper:
"Integrating Electronic Equipment and Power into Rack Enclosures"
'Optimized Power Distribution and Grounding for Audio, Video and Electronic Systems'
http://www.middleatlantic.com/resources/white-papers.aspx

Jim Brown paper:
Power and Grounding For Audio and Audio/Video Systems
-- A White Paper for the Real World

This White Paper was commissioned by New Frontier Electronics (the SurgeX people) so they would have something to pass out to contractors and other users of their excellent power products.
http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

Bill Whitlock 2012 seminar paper:
An Overview of Audio System Grounding and Interfacing
by
Bill Whitlock, President
Jensen Transformers, Inc.
An audio system is rarely a plug-and-play affair. Noises often plague the
system even if everything is done according to conventional wisdom. Did the
electrician screw up? Is the AC power dirty? Is the equipment to blame? Are
the cables poorly shielded? This presentation will discuss the "secret" forces
that drive ground loops, how they contaminate our signals, and new tools to
make troubleshooting faster and easier. Among the topics will be equipment
design errors that can make life miserable for installers and users, how
manufacturers manipulate "specs" to deceive, how new test standards and
instruments can make manufacturers honest, why expensive cables probably
won't help, and things your electrician can do to reduce or eliminate problems.

http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
 

sbo6

VIP/Donor
May 18, 2014
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480
Round Rock, TX
Great info, thank for the link..

Everything you need to know about AC power for audio/video installations and a whole lot more.

Middle Atlantic Products paper:
"Integrating Electronic Equipment and Power into Rack Enclosures"
'Optimized Power Distribution and Grounding for Audio, Video and Electronic Systems'
http://www.middleatlantic.com/resources/white-papers.aspx

Jim Brown paper:
Power and Grounding For Audio and Audio/Video Systems
-- A White Paper for the Real World

This White Paper was commissioned by New Frontier Electronics (the SurgeX people) so they would have something to pass out to contractors and other users of their excellent power products.
http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

Bill Whitlock 2012 seminar paper:
An Overview of Audio System Grounding and Interfacing
by
Bill Whitlock, President
Jensen Transformers, Inc.
An audio system is rarely a plug-and-play affair. Noises often plague the
system even if everything is done according to conventional wisdom. Did the
electrician screw up? Is the AC power dirty? Is the equipment to blame? Are
the cables poorly shielded? This presentation will discuss the "secret" forces
that drive ground loops, how they contaminate our signals, and new tools to
make troubleshooting faster and easier. Among the topics will be equipment
design errors that can make life miserable for installers and users, how
manufacturers manipulate "specs" to deceive, how new test standards and
instruments can make manufacturers honest, why expensive cables probably
won't help, and things your electrician can do to reduce or eliminate problems.

http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
 

Folsom

VIP/Donor
Oct 25, 2015
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Eastern WA
IG is good for use in power conditioners and other distribution boxes that use metal boxes, if they also incorporate a form of ground loop breaking. Outside of that they're not of any particular value for the home. Funny, however, they might be worse if you had a metal box without metal conduit.

JPS labs in wall wire is twisted already. Cardas sells untwisted wire that's not as expensive, and VH audio sells cryo'd Romex. Those are all ones that work without having to twist yourself and install in conduit.
 

Speedskater

Well-Known Member
Sep 30, 2010
941
15
368
Cleveland Ohio
IG is good for use in power conditioners and other distribution boxes that use metal boxes, if they also incorporate a form of ground loop breaking. Outside of that they're not of any particular value for the home. Funny, however, they might be worse if you had a metal box without metal conduit.
no.

**************************************
added content
You might read Ralph Morrison's 1990 book:
"Grounding and Shielding in Facilities"
Chapter 7 'Facility Considerations'
 
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GaryProtein

VIP/Donor
Jul 25, 2012
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NY

Folsom

VIP/Donor
Oct 25, 2015
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Gary I know beyond all doubt that if I'm trying to stop a ground loop using a special inductor that saturates so it's safe on the ground, I must use an isolated ground socket in a powerstrip or such that has a metal enclosure. If I don't, then the loop forms through the enclosure. Kevin knows a ton of information , but when it comes to this particular snippet he can sit on it, because he's adamantly wrong. I often trust him but sometimes it's empirical non-sense, that's only recommended by him because someone wrote about instead of trying it. That's rare, but it occurs.
 

DaveC

Industry Expert
Nov 16, 2014
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495
I value SS's input but I agree it's not likely he's had actual experience with some things, especially "audiophile" receptacles, cables, etc...

I know you (Folsom) were skeptical about the $$$ Furutech GTX receptacle but you were willing to give it a try and now you know exactly what it's capable of. Coming up with an explanation for the relatively radical change in sound due to adding a single GTX receptacle might be difficult, but the results are more than a little audible.

As I said in the JBL 4367 thread, it baffles me how people who claim to adhere to "science" are completely unwilling to do actual experiments despite a huge amount of anecdotal evidence that should be more than enough to form a hypothesis. It's about the least scientific approach I've ever witnessed and is far closer to dogma or religion than science.
 

es347

VIP/Donor & WBF Founding Member
Apr 20, 2010
1,577
35
970
Midwest fly over state..
..got an email from Audio Advisor showing new duplex receptacles from Pangea. The specs are impressive..
 

Speedskater

Well-Known Member
Sep 30, 2010
941
15
368
Cleveland Ohio
Gary I know beyond all doubt that if I'm trying to stop a ground loop using a special inductor that saturates so it's safe on the ground, I must use an isolated ground socket in a powerstrip or such that has a metal enclosure. If I don't, then the loop forms through the enclosure. Kevin knows a ton of information , but when it comes to this particular snippet he can sit on it, because he's adamantly wrong. I often trust him but sometimes it's empirical non-sense, that's only recommended by him because someone wrote about instead of trying it. That's rare, but it occurs.
Are you suggesting that:
Jim Brown
Ralph Morrison
Henry Ott
Bill Whitlock
and other experts
are also wrong?
 

Folsom

VIP/Donor
Oct 25, 2015
6,024
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520
Eastern WA
No. I'm not saying anything about them. Maybe your interpretation is incorrect. Nothing I've read by any of them indicates the ludicrous notion that you can break a ground loop by forming an alternate path for the loop with the difference of a few inches, that still runs through the same cords.
 

YashN

New Member
Jun 28, 2015
951
5
0
Canada
Are you suggesting that:
Jim Brown
Ralph Morrison
Henry Ott
Bill Whitlock
and other experts
are also wrong?

Next thing Folsom will do is send you a PM, then try to see if he can sell you his 'AC Filter' box, which is badly constructed by the way, then when he realises you know what you're talking about, he'll start calling you 'troll' in the forums.

You may already have come across him on AC, as Folsom recently and Salis Audio in the past where he got schooled in the intricacies of AC power grounding and security by a few people. Since then, he changed his nick.
 

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