More questions about dedicated lines


We are moving to a new house built in 2007  and I am fortunate enough to be able to move a wall to create a room with golden ratios. I will need to run some new electric and it gives me the opportunity to run dedicated lines.  I have spent countless hours rummaging through the 7k discussions on this topic and have a decent idea of what is needed.  My plans are to have four runs of Romex 10/2, one each for each monoblock VAC signature 200's, my digital, and my Audiokinesis swarm which has not be set up yet.  I estimate the runs to be conservatively 45 feet including up and down distances. All runs will be of equal length ending in SR  outlets. They will be separate from each other and all other lines and no metal staples will be used.  When I told him I my goal was to have the best sound he offered a suggestion that I hadn't come across in my electrical education here on the gon.  He suggested placing what sounded like a commercial power regenerator with a large battery bank as the first step out of the breaker box and running lines from this.  The other options were to run from a preexisting sub panel that has the pool pump and a few lights on it, but nothing else.  Third is straight out the breaker box.  He wanted to put the runs closest to the utility line in, stating that there will be less noise upstream than downstream, but this puts these lines next to a big double breaker (cant' remember what it is but is sure to be noisey).  He understands that I want all lines on the same phase, or line,leg.  My questions are: Of the three options, which would be best?  Is there anything else needed to minimize the risk of ground loop hum if I use separate hot, return, and gound for each line and not share ground neutrals and keep all lines separated from themselves and other lines.  If going through a subpanel with little on it, how do I manage to keep all runs on the same phase without unbalancing the breaker? A third tangential question-Is it best to use metal or plastic housing boxes for the receptacle? The question of durability of the plastic fatiguing and breaking following repeated plugging and unplugging has been mentioned but I didn't see an answer.  Finally, a huge thank you to jea and almarg for their voluminous responses in all the prior electrical discussions-I got an education.  Sadly, I still don't speak electricalese.
orthomead
The battery bank config sounds interesting, but I would consult better minds- like Almarg and Jea48. If I recall correctly, Atmasphere recommended a power conditioning unit, and it looked pretty serious, but I can't remember the name. Hopefully, he will chime in, too.
The second sounds the worst, in my opinion.
The third would be my choice. In fact, that is what I am using for my main system, and hopefully, my office in the near future.
Bob
Thanks for your input, Bob.  I am leaning in your direction and hope Jim and Al will chime in as well.  I'm assuming since you will use the same set up that you're happy with the sonics and haven't had ground loop issues.  How many lines did you run and what was the distance from the box to outlet if I may ask?

Orthomead and Bob, thank you kindly for the nice words. And kudos, Orthomead, for having done such thorough research.

Regarding the power conditioner Bob referred to, which is no longer made but was formerly produced by Elgar, see Atmasphere’s post dated 10-7-2016 in the following thread:

https://forum.audiogon.com/discussions/power-conditioner-help-3?page=2

… as well as the two posts dated 5-20-2016 by Dragon_Vibe in this thread:

https://forum.audiogon.com/discussions/what-does-a-power-conditioner-really-do.

However given the weight, expense, probable need for refurbishment, and marginal availability of this unit I suspect you won’t want to pursue this approach.

Regarding keeping the two AC legs from becoming significantly unbalanced, I would infer from the literature on your VAC amps that they operate primarily in class AB, since only the input and driver stages are described as operating in class A. And given their 200 watt rating in mono mode I suspect that aside from occasional very brief dynamic peaks in the music each amp will probably be supplying well under 100 watts to the speakers, with the two amps together consequently drawing no more than about 500 watts of AC. With the system as a whole probably drawing no more than 800 watts or so most of the time, including the sub amp. Which seems to me to be sufficiently low that keeping the legs in balance is a non-issue, regardless of which of the three approaches is chosen.

Regarding ground loop susceptibility, while connecting different parts of a system to separate dedicated lines can be advantageous by minimizing coupling of noise among the various components, it can also sometimes increase susceptibility to ground loop issues. So there is a tradeoff involved, which generally has little if any predictability. But with the four dedicated lines you’ll have a lot of flexibility in terms of what gets plugged in where, and if a ground loop issue were to arise with the connection arrangement you’ve described you’ll have other alternatives available which should eliminate it.

I have no suggestions to offer as to the choice of metal or plastic for the outlet housings. Perhaps Jim will chime in on that.

Finally, regarding the three approaches you’ve asked about:

Regarding the possibility of using the large commercial regenerator that was suggested by the electrician, if I understand correctly this sounds as if it may be something like a very powerful UPS (uninterruptable power supply). If so, what I would ask about is the possibility that the circuitry in it might generate significant RFI (radio frequency interference). I can tell you that if I bring a portable battery powered radio within a foot or so of the relatively small UPSs I use for my computer systems (which are the type that generates true sine waves, not stepped approximations of sine waves as is done by many inexpensive UPS devices that are presumably more noisy) the high frequency noise radiated by their circuitry is picked up very strongly in the AM band.

Regarding a choice between the other two options, it’s possible that option two as well as option three would be good choices if the pool pump and the audio system would rarely be in use at the same time, and if the wiring between the main panel and the sub-panel is of sufficient gauge. But with the heavy gauge you’ll be using for the dedicated lines and the reasonable lengths that are involved voltage drops in the dedicated lines figure to be insignificant with either approach, while the increased inductance of the greater length that I assume would be needed for option three may provide a bit more filtering of high frequency noise. So my instinct would be to agree with Bob, that the third option is probably a better bet than the second.

Good luck. Regards,

--Al


The battery bank, hands down. Only close to the room, not panel. Then run one large gauge line to your power conditioner. Everything plugs into that. None of this multiple lines stuff. With the battery regeneration you can further improve the pseudo off-grid situation by putting that same circuit (to the conditioner) on a dedicated ground. An actual copper stake in the ground ground. Everything system plugs into that. And nothing else. Everything else, lights, etc, run as many lines for that as you want.

Something nobody ever seems to think of in the race to recommend more and more stuff, is every wire is an antenna. Its what an antenna literally is- a wire. Every wire in the house is an antenna. Each one gathering RFI & EMI noise. So why on Earth would you want to be running more of those into your system? Anyone? Beuller?

And oh, I know, the battery with the ultra-pure power? Let's put it as far away from the system as we can, and run as many wires as we can... this is what passes for "thinking" on the inter web.
With your grounds only connected at the breaker panel AND through ICs, that is a recipe for ground loops. I ran 6 awg to a mini panel with the outlets right next to it at my system. Not sure why more don't do it.
I run 8 awg solid core for analog and 10 awg solid core for digital and one dedicated 5 meter grounding rod.
Two 20 amp lines of 10awg on the same phase is enough for 99 percent of installations
Agree w.r.t. a power draw, but how would you connect grounds?

Two 20 amp lines of 10awg on the same phase is enough for 99 percent of installations

What spinaker01 said, +1.     Did that(two 10/2 runs, with a twist, to avoid induction), a few decades ago, with excellent results.
@OP, 
I ran 3 direct lines. One for source, and one each for my monoblocks and subs.
The distance from breaker box to outlets varies.
12 feet to amps, 20+ feet to source.

My one concern with choice #2, is having a system on the same line as the pool pump. What happens when both pump and stereo are run at the same time?- Maybe it is a non issue, but, if since you are going this far, why not give yourself every advantage and go the safest route.
Ground loop hum is a b*tch, I have it on my office system, and I wouldn't wish it on anyone.

Hopefully, the electrician will have some time soon...
B
Firstly, thanks to everyone for their input.  I suspect this is one of those topics where there may be no perfect approach but the discussion of multiple paths may coalesce into a good solution for my system .
Al, the Elgar sounds awesome-too bad it is no longer produced and supported.  I suspect that the option of running off the main panel may be the best.  gdnrbob, I too am concerned about the pool running during listening times.  If we do run off the main panel, any thoughts about what order in the breaker box the lines should come.  First closest to the mains input with bigger utilities close by or at the end of the line?  Prior discussions seemed to favor distance from the bigger power consumers.

Millercarbon also raises a good point about multiple lines behaving like a big antenna.  All prior posts that I reviewed with single lines had no problems with noise, but not all with multiple lines had issues either.  If I do run multiple lines off the breaker and I do run into noise, I could always place every thing on one line as Millercarbon suggests.  The cost of running extra lines is minimal and it does give me a fail safe. Unfortunately, the electrician was a little nebulous about the actual product he had in mind for a battery bank.  I do like the idea and I will try to pin him down to a more specific and concrete item.  I am open to suggestions if you have them.
There seems to be no consensus on how many lines are necessary and at what point we reach overkill, or worse-more noise.  For spinaker and rodman- what components do you have on each line? Are you running subs on the same line as the main amps?
In terms of grounding, tecknik, my basic understanding is that all grounds have to be interconnected to meet code. My electrician did mention adding another ground though.
audiozenology-I am a little confused.  Do the outlets off the sub panel have a different wiring configuration? Or is it the shorter runs that make the improvement.  Some have suggested that additional connections may be more problematic.
Again, thank you so much for your input
orthomead,
I am running a single 6 awg connection (line/neutral/ground) to a mini - 6 location panel right behind my system. I only have 3 breakers installed. That runs to 3 double outlets on the other side of the stud. The wire lengths are quite short, about 16". I used 20A outlets as they would accept 10awg. I can always run a separate ground to this mini panel, but don't see a need.
audiozenology- Are some lines on a different phase or line,leg? If not, how did you balance the minipanel, or is that only necessary on the main breaker?  This is a point of confusion for me.  If the lines are on different phases to balance the mini panel, doesn't that compromise sound?
@ orthomead

+1 almarg post on 12-15-2019


almarg9,244 posts

12-15-2019
8:14pm


Regarding keeping the two AC legs from becoming significantly unbalanced, I would infer from the literature on your VAC amps that they operate primarily in class AB, since only the input and driver stages are described as operating in class A. And given their 200 watt rating in mono mode I suspect that aside from occasional very brief dynamic peaks in the music each amp will probably be supplying well under 100 watts to the speakers, with the two amps together consequently drawing no more than about 500 watts of AC. With the system as a whole probably drawing no more than 800 watts or so most of the time, including the sub amp. Which seems to me to be sufficiently low that keeping the legs in balance is a non-issue, regardless of which of the three approaches is chosen.

Using Al’s (almarg) calculations for total average energy usage of 800 watts would not be a problem, imo, putting the four 20 amp dedicated branch circuits on the same Line , leg.


One 120V 20 amp (2400 watts) branch circuit would easily handle a 800 watt load. Spreading, separating, the loads of your audio equipment across 4 branch circuits will not change the total connected load.

800 watts / 120 volts = 6.7 amps. 6.7 amps will not cause a significant imbalance load on the electrical service of your home.
The average portable vacuum cleaner has an FLA of 12 amps. A portable electric space heater 1500 watt @ 125V, 12 amps. An average microwave oven 1200 watts, 10 amps @ 120V.

Using 10-2 with ground Romex (NM sheathed cable) where the total length is 45ft should rule out the chance of ground loop hum..... Should..... I can’t count all the threads I have read over the years where monoblocks were/are used where the user is fighting ground loop hum problems.

Here is just one running now.
https://forum.audiogon.com/discussions/krell-kas-amplifier-hum

@Atmasphere explains most ground loop hum is caused by the audio equipment itself. Poor design in the way the designer connected the circuit ground/signal ground to the AC mains safety equipment grounded chassis of the equipment.

Jim
A single set of wires to the mini-panel. One live, one neutral, one ground. The balancing is done at the main panel, but realistically, balancing is a very rough exercise at best these days. No matter how big your breaker to your audio system, unless you are running lots of high power Class-A, the average current draw is fraction of the breaker rating even when the volume is high.

With all that you are doing to improve performace I would suggest using 

high purity audio grade thru the wall cable .

Since Cardas no longer makes it you might look into JPS .



Size: 10 AWG, UL/CSA listed for in-wall use

Design: Optimized Field Matrix (OFM) construction

Price: $18 per foot

 

Company Information

JPS Lbs
4893 Transit Road
Suite 150
Depew, NY 14043

Voice: (716) 656-0810
Fax: (716) 656-0811
E-mail: info@jpslabs.com
Website: www.jpslabs.com


My 6/2 was $1.50 / foot. The mini-breaker panel was $120 with the breakers.  I would say I am way way ahead of $18/foot wiring and with less losses on power peaks.
 orthomead ,
I would suggest that you only need 2 lines not 4 ,
with the equipment and power requirements you have .
( just my opinion as a retired biomedical equipment technician )

As for romex or premium in the wall cable  ,
there have been many discussions about how could a 6 ft. power cord  
( or outlet ) make a difference in the sound of your equipment , 
if you using expensive power cords because you can hear a difference then you should consider quality in the wall cable,
if you don't and are using off the self 12 or 10 gauge power cables then use whatever to get power to your outlets .
( just my opinion as an audiophile DYIer )


p.s.  I looked at jps and maybe they don't produce in wall anymore ,
        but it looks like Oyaide still does , Cardas still has 10/3 listed on                  
        their web site but I haven't seen anybody selling it .

 
orthomead

In the April 2019 edition of The Absolute Sound magazine
Robert Harley wrote about building a listening room .



Thanks Jim, that puts me at ease.  Any thoughts on whether metal or plastic recepticle boxes are best? It sounds like plastic may be a better sonic choice but at the risk of being less durable.Audiozen-the light went on and I understand now. Thanks.Vair68robert-I devoured the article.  I thought the wall construction was fascinating and made a lot of sense.  I will be adding only one wall but will take some ideas for that without doing the whole shebang. I think I will just stick with the Romex 10/2-thanks.My electrician wanted to powow with some colleagues who do high end AV and is getting back to me.  Glad he is looking into all options too.  I'll post his ideas when I next talk to him.  Again, thanks everyone for your input
Keeping an eye on this thread as I am also building a Dedicated sound/play room. 27 x 18x 10.6. So real close to the Golden Ratio. Duke building my Swarm system as I type. Going with an ISO Max wall system. Mini split system will heat and cool so no duct work to worry about.  Native 200 amp electrical 
Started off as strictly 2 channel but figured I will build an Atmos system with high quality in walls and ceiling speakers
I built a new garage in front of my existing garage which is being converted into the play room. Per code I had to install a ground rod in the footing of the new garage.  Should I use this for my dedicated circuits?  I feel my power is pretty quiet now and will be happy just staying status quo. 
My electrician thinks I am nuts already. He definitely agrees with dedicated circuits but he thinks a lot of the other stuff is over the top and offers little benefit. 
Never heard of not using metal stables. What fasteners does everyone recommend ?
Will be built on a 2x8 sleeper floor over the existing cement floor. Any ideas on that? Figure it’s a great time to work on stiffening up the floor as I can basically layout my system prior to installing the decking. 
Demo starts after Christmas. Hopefully be done by the end of February. Pretty excited about this. My original plans where from 2003 but divorce and economics got in the way. 😀😀
@ orthomead

1 gang new work plastic boxes have more internal space/area than 1 gang new work steel switch boxes. Home Depot carries good quality plastic boxes.

+ 1 on using deep boxes when using #10 Romex. Your electrician will/should already know that.

vair68robert156 posts12-18-2019 10:50pmOne more of my opinions ,
use an extra deep outlet box .

This is definitely something you will never regret later!

@ orthomead


Just curious,


Where is the main electrical panel located? Example, garage, laundry room, mechanical room, on the outside of the house. Manufacturer of panel? Electrical panel main breaker size?

Where is the sub panel located?
How big is the sub panel, ampere rating? What is the handle ampere rating of the 2 pole breaker in the main electrical panel that feeds the sub panel? (Number is on the breaker handle) How many empty spaces are left in the sub panel? Number of empty spaces on each side? Panel manufacture?

Any idea how big, horse power rating, the pool pump motor is? Voltage rating? 120V or 240V? Is the motor controlled by a VFD (Variable Frequency Drive) controller?


I think you should use a separate 20 amp line to each amplifier. Use three wire Romex just in case you ever want to run a 220 volt amp. Then you need one other 20 amp line to a power conditioner/surge protector. I use a Furman 2400 IT which I can not recommend highly enough. All my other equipment is plugged into it. All grounds should go back to the panel. Ideally all signal connections should be balanced including your turntable. Any standard outlets will do. Spend the money on your power conditioner. Audiophile outlets are a bad joke like cable elevators. 
Ouch. Oh well. There are those who "know" because they "think" and there are those who know because they have done- AND HEARD.

I find solace in thinking those who throw away vast sums on bad advice have such vast sums they won’t even notice.

One thing I cannot quite figure out though. If the whole point is to get better sound, why take advice from people who say right up front they can’t hear? Especially when at the same time they are admitting they don’t know, because they haven’t done?

Oh well. Your money. Throw a match, watch it burn for all I care.
Wow ..... that is some serious sour grapes. I will repeat what Almarg posted, and point out the obvious inverse/square law, i.e. RF sources nearby will have far more impact than distant ones:

Regarding the possibility of using the large commercial regenerator that was suggested by the electrician, if I understand correctly this sounds as if it may be something like a very powerful UPS (uninterruptable power supply). If so, what I would ask about is the possibility that the circuitry in it might generate significant RFI (radio frequency interference). I can tell you that if I bring a portable battery powered radio within a foot or so of the relatively small UPSs I use for my computer systems (which are the type that generates true sine waves, not stepped approximations of sine waves as is done by many inexpensive UPS devices that are presumably more noisy) the high frequency noise radiated by their circuitry is picked up very strongly in the AM band.

Use three wire Romex just in case you ever want to run a 220 volt amp.


You don’t need a 3 wire with ground Romex cable for 240V. A 2 wire with ground Romex is all that is needed.


Problem with using a 3 wire with ground Romex cable for a 2 wire circuit is what do you do with the unused conductor? Ground it? Leave it floating, taping both ends?
Floating the unused wire will act as an antenna and will introduce RF noise onto the circuit conductors.

If the unused wire is grounded because of the lay, position, of the conductor in the Romex cable, the hot and neutral current carrying conductor’s magnetic fields will induce a voltage on the grounded wire. Result is a ground loop and hum.

Worth mentioning again, as I have mentioned before in other posts, two conductor with ground NM sheathed cable (Romex) is not the best branch circuit wiring for controlling induced voltage from the magnetic fields of the hot and neutral current carrying conductors. The reason is because the paper filler that surrounds the bare ground wire does not rigidly hold the ground wire centered between the hot and neutral conductors. Twisting the Romex cable, imo, would make it even worse, not better.

A better Branch circuit wiring is 3 wire MC (Metal Clad) armored cable. (Hot, neutral, and green insulated ground) The 3 wires are tightly held together in a spiral twist housed inside a metallic armor. MC cable is manufactured with a steel armor or aluminum armor. Also manufactured with solid or stranded conductors. (Solid wire is recommended for audio branch circuit wiring.)
Example of MC armored cable.
http://www.afcweb.com/mc-metal-clad-cables/mc-lite-aluminum-armored-cable/

Best branch circuit wiring is to twist the hot and neutral conductors together and install the equipment ground along side the twisted pair in a conduit.

Jim
.

jea48,

This is why I would never recommend multiple runs from the breaker panel unless the grounds are tied at your stereo system.  This is why I ran a single heavy gauge to a mini panel and then put the outlets right next to it.
audiozenology96 posts

12-20-2019
9:28am

jea48,

This is why I would never recommend multiple runs from the breaker panel unless the grounds are tied at your stereo system. This is why I ran a single heavy gauge to a mini panel and then put the outlets right next to it.

@ audiozenology

Why do audiophiles have multiple 20 amp branch circuits installed when in most cases one 20 amp branch circuit would be plenty big. The OP audio system has a total average continuous connected load of around 7 amps? (Music playing at a moderate to load listening level.)

It has been a while, and I no longer have the posts in my favorites, from two well respected EEs that posted on the Audio Asylum audio forum. When I get a chance this weekend I will check the archives to see if I can find them.

Just going from memory though it has something to do with decoupling the power supplies of audio equipment from one another. Especially digital equipment from analog. Distance, length, of the branch circuit wiring has something to do with it.

Jim


The problem with power supply decoupling through multiple lines is that unless you couple the grounds at your system, you are now injecting differential ground noise, which arguably is worse.

The concern with amplifiers is not average draw, but peak draw, which for an AB amplifier could easily be several times the fuse/breaker rating even though the average draw is far below the fuse rating. Over a 45 foot run, that could cause a large voltage drop at the top and bottom of the AC waveform when the amplifier capacitors are charging. For that reason, a 10awg run may not be sufficient  (though the resistance may reduce EMI).  I run a single 6awg, mini panel, outlets close by. That makes individual ground runs short between equipment, and a low resistance run back to the panel. I think it is a good compromise.
So if I am finally starting to understand, Audiozen, that by running a large gauge wire to a minipanel, all lines from the minipanel are on the same phase relative to the main box and main power and shorter multiple strands reduces the size of any antenna effect? Is the minipanel in a closet or out of direct sight.  I could do this with the closet that will be next to the wall where the outlets will be. And if I'm understanding Jea correctly, I flunk my Agon review.  Soo, for my purposes, if running multiple dedicated lines from the breaker to the outlets, 3 wire metal clad would be superior to Romex?  At least I'm totally clear that a deeper plastic outlet box is the way to go.  Benzman, in terms of no staples, my electrician would suspend the wires with two interconnected plastic ties, one of which suspend the wire, the second would be nailed to wood. Your room sounds awesome, by the way.  Please keep us updated. Thanks again everyone for your interest and help.
Much like everything else, the only way to really know is to try and listen. Standard audiophile practice is to change only one thing, since if you change several things at once its impossible to know what did what.

Logically then it is at least unlikely, if not downright impossible, to know which of all these different ideas is going to work best without having actually tried and compared.

Who here has done that?

I mean, besides me?
Is there a reason you don’t want to do as the electrician you consulted advised? Why not get a second opinion from another one in your area who is familiar with local codes and can give an opinion based on what he actually sees is doable in your house.
Regarding option #2, which hasn't gotten a lot of support, there may be a way to improve.  It is called a "soft start" for motors, mostly used on A/C units, but I also found the "EasyStart 364" which might work for a pool pump.  I'm NOT an electrician, so don't just grab one and slap it on without consulting the qualified electrician.  I would be interested to hear his opinion.  I can say that I have the "soft start" for both my A/C units, mostly installed just to avoid that chance of both starting simultaneously.  The only drawback is they are IMHO a bit expensive.  It is also supposed to help the lifespan of the motor, but I'm not sure if that is reaching a bit or not.
If you really wanted to do something drastic, you could take the pool pump off-grid with a solar pool pump, but of course that is running up into a more major investment, but in the long-run might prove to be economically viable.  It would run even during a power outage, of course only during the day, but you wouldn't have to worry about the pool turning green if power is out for several days.
Miller,


You are not the only one who has implemented things. Are you even reading the posts?
@ millercarbon


read pages 11 thru 13.
https://www.anixter.com/content/dam/Images/Logos/Supplier-Logos/Middle-Atlantic/PowerPaper.pdf


read pages 31 thru 35
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

FWIW, I used 10-2 w/grd NM sheathed cable for the two 20 amp dedicated branch circuits for my 2ch audio system. Each cable is 75ft long......
My system is dead quiet...

Job layout and the wiring method used makes the difference.
.
I think I'm getting somewhere here thanks to y'all.  Jim, the PowerPaper you referenced indicated that there were two sheathing options-aluminum or steel and the article further references the aluminum sheathed hospital grade cable.  Of these 3 options, what would you currently choose? Are all your components plugged directly into the wall or do you use a power strip and/or conditioner/regenerator?

Tribbles-I'm looking to have good sound and stay married.  My wife has given me a lot of leeway and I will be in the doghouse if I suggest we need to redo the pool electrical so my room will be better!  Thanks for an outside the box thought, though.
djones-my electrician had several thoughts and I'm trying to decide which will be best.  He didn't come out with a concrete plan and besides, all the prior postings I reviewed seemed conclusive that less than optimal outcomes are likely without the audiophile's input.
jea48,


What are you doing posting articles by actual engineers who understand the topic. Don't you know that "book smart" engineers couldn't possibly understand "audio"? All they know is numbers ;-)

Orthomead, if you skim over the articles that jea48 posted, they discuss why running multiple lines is not a good idea (highest potential for differences in the ground potential between the outlets. jea48's wire choice worked to negate induced ground potentials. I ran a single heavy gauge to eliminate ground potential differences between equipment (and used


My mini panel is in the wall behind my equipment rack. There is a small acoustic panel over top of it.
orthomead

I believe that audiozenology explained the best set up .
Run a heavy gauge wire like 6 awg from your main box to a mini or remote box as close to your new outlets as possible , then you could run 
Audience 10 awg wire to your outlets ( like AudioQuest's NRG Edison ) .

I believe that jea48 has a point about Romex , 
if you could run conduit it would be a better option ,
then you could use metal outlet boxes !

One thing I've learned is that Audio needs more gauge and more n's
in our power wires .

Your going to have a fantastic power base for your current system
and the future upgrades .

orthomead OP28 posts

12-21-2019
2:36pm

I think I’m getting somewhere here thanks to y’all. Jim, the PowerPaper you referenced indicated that there were two sheathing options-aluminum or steel and the article further references the aluminum sheathed hospital grade cable. Of these 3 options, what would you currently choose? Are all your components plugged directly into the wall or do you use a power strip and/or conditioner/regenerator?



@ orthomead

MC aluminum armored cable is more widely used than steel. Aluminum will help shield from RF noise but not AC magnetic fields. The steel armor helps reduce AC magnetic fields. Though the twisting of the current carrying conductor does most of that. The steel armor will help protect the conductors of the MC cable from close near by parallel running NM cables from induing an AC voltage, AC noise, onto the conductors of the MC cable.


If aluminum armor MC cable is used it should be kept, spaced, from other branch circuit wiring probably a safe distance would be 8" to 12" or so. 8" would be enough but 12" would be safer. (Within reason after getting out of the electrical panel and starting the parallel runs, of the dedicated branch circuits, as well as any existing parallel running NM (Romex) branch circuits, as they are being installed to the audio room and down the wall to the outlets.) (With Romex you need to pay more attention to cable separation.)

FWIW.
(I am not a fan of 4plexs, 2 duplex outlets (for two dedicated branch circuits), sharing the same outlet box. Kind of defeats the purpose of dedicated circuits separation. Also worth mentioning if wall warts are used, depending on the physical size of the wall wart, it blocks part of the outlet on either side of it.

If you want to use the steel armored MC cable I wouldn’t be surprised if the electrical contractor will have to special order it. I suppose it depends on amount of usage of steel armored MC cable in your State, area, though.

As for hospital grade MC armored cable it has two equipment ground wires. One bare ground that runs along side the spiraled twisted circuit conductors, (to bond, connect, the equipment grounding conductor to the steel outlet box). The other grounding conductor is a green color insulated wire for an IG, (Isolated Ground) type outlet). (This insulated green wire is tightly held in place and twisted in a spiral together with the black and white current carrying conductors.)

You don’t need to use IG outlets in a single family dwelling house structure. IG outlets aren’t used that much anymore and when they were used they were used in commercial and industrial facilities where branch circuit steel conduits are fastened to other steel objects. The theory is AC noise is traveling all over the place through the interconnecting steel and other electrical steel conduits.



Of these 3 options, what would you currently choose?
This is a question you really need to have with the electrical contractor you are working with. He has been on site and is better qualified to assess your situation. For one thing can he keep the 4 dedicated MC armor cables separated from one another after he gets out of the electrical panel, as well as other parallel running branch circuit wiring. As for me, I would go with the aluminum armor MC cable.

ONE THING FOR SURE! Make sure you tell the contractor you want #10awg SOLID wire. Not Stranded wire...... Make sure he understands you want solid.... Don’t let him try to talk you out of it. He will tell you the ampacity rating is exactly the same, and yes it is. Your audio system won’t sound the same though. Solid wire only.


Are all your components plugged directly into the wall or do you use a power strip and/or conditioner/regenerator?
Yes directly plugged into the wall outlet. No power conditioner.
And again, I used NM (Romex) cable. Your situation may be different than mine though. I didn’t feel the need to spend the extra money for the MC armored cable.

If you don’t mind having a sub panel installed in your audio room you may want to go that route. One factor to consider though is resale of the home.


Best place to Install it is in the new wall you will be building. Speaking of the new wall you may want to consider building a double wall with staggered studs. Leave a slight space between the two framed walls. A 1/2 inch to an inch would probably be plenty.


Per the NEC, and I’m pretty sure the AHJ (Authority Having Jurisdiction) in your city, the electrical panel must be readily accessible and have a clear working space in front of the panel. Your electrical contractor can tell you what the minimum front and side distance measurements are.


If you decide to have a sub panel installed, because of the cost of the installation, (material and labor), you should add plenty of a fudge factor for future. It’s a lot cheaper now than later if you decide to buy bigger amplifiers.


I would wire sub panel for 120/240V. With your present audio equipment you can still feed all the 4 dedicated circuits from one Line, leg. With both Lines, Legs, available you have the option to easily move the dedicated branch circuits to the Line, leg, for what ever reason if you so choose.

Sub Panel Feeder:
If it were me I would feed the sub panel with at least #4awg copper or #2awg aluminum conductors. I would oversize the equipment grounding conductor as well.
If the electrician used #4 copper, (or #2 aluminum), he could use a 2 pole 70 amp, or a 2 pole 80 amp, breaker at the main electrical panel. Code only requires a #8 copper for the equipment grounding conductor. I would probably bump it up to a #6 copper wire.

Overkill? Yeah, probably...... But consider you want four 120V 20 amp dedicated circuits, using #10 wire, to feed an audio system that draws around 7 amps.


Combined wire gauge calculator.
https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html

Enter 4 for the number of wires.
Enter #10awg for wire gauge.4 #10s = #4awg.

Jim

jea48

Heck of a lot of good advice in that post!

If you are in a major city, I don't think you will have too much trouble finding steel armoured cable. Most of the major electrical distributors will stock it, though maybe not in their branch outlets, so you may have to order today, deliver tomorrow. I also used Romex as I have a dedicated run with nothing near it.


My brain is starting to go into Christmas shutdown mode, so I am not sure I am 100% accurate when stating that using 120/240 will create unbalanced current which could cause ground injection. Assume I am wrong, but please check my work.

One consideration, whether you wire for 120/240, if you use 6/3 (or 4/3), you can buy round (and twisted) instead of flat.

+1 on the double wall. Also consider resilient channel if you want some sound deadening.

I am not sure your reasoning behind using solid core (and not stranded), but I agree with the choice as well. The transformer in your equipment only has limited bandwidth, and anything beyond a few KHz to support required transient current delivery due to only conducting for part of the AC cycle (linear power supply), is just providing a convenient path in and out for noise.



EDIT:
jea483,227 posts

12-22-2019
1:57pm


Sub Panel Feeder:
If it were me I would feed the sub panel with at least #4awg copper or #2awg aluminum conductors. I would oversize the equipment grounding conductor as well.
If the electrician used #4 copper, (or #2 aluminum), he could use a 2 pole 70 amp, or a 2 pole 80 amp, breaker at the main electrical panel.


I just used the NEC ampacity rating of the wire to size the 2 pole breaker for the feeder. Going back this AM and rereading what I posted yesterday I should have posted a 2 pole 60 amp or a 2 pole 70 amp breaker. It could even be a 2 pole 50 providing the wire lug size is big enough for #4 copper or #2 Al (aluminum) wire.

Example Square D is listed at,
35A - 70A
  • 1 wire per lug: (1) #8 - #2 AWG Aluminum or Copper
https://www.se.com/us/en/faqs/FA237923/




@ audiozenology

If you are in a major city, I don’t think you will have too much trouble finding steel armoured cable. Most of the major electrical distributors will stock it, though maybe not in their branch outlets, so you may have to order today, deliver tomorrow.
You would think so. But unless there is a demand for steel armor MC cable, Electrical Wholesale Houses, today anyway, don’t stock items that just take up self space.
I called 4 large wholesale houses this morning and none of them stocked the steel armor MC cable.


My brain is starting to go into Christmas shutdown mode, so I am not sure I am 100% accurate when stating that using 120/240 will create unbalanced current which could cause ground injection. Assume I am wrong, but please check my work.
Not sure I follow, please explain.
Remember in the OP’s case his average load is around 7 amps. #4awg copper is rated for 70 amps (60 degree C, 140 F) and 85 amps (75 degree C, 167 F, THHN/THWN)
(There are factors that may apply for the adjusted ampacity rating of the wire.)


The circuit is through one of the feeder’s two hot legs and the feeder’s neutral conductor, a 7 amp load is insignificant in the scheme of things in my opinion.

Jim


Jea and audiozen-I can't thank you enough for all the time and energy put into helping me.  I feel that I am on real solid ground and will be able to convey to the electrician the direction and details necessary.  BTW these two approaches were discussed as options when the electrician made a site visit more in theory, as in we could, but without any of the details.  You have provided those details and I thank you.  I will keep you all posted as this plays out.  Merry Christmas and a happy new year to all.

Leon
Millercarbon, taking advise from a person who can't hear is better than taking advice from a person who is delusional. The vast majority of us have a limited amount of money to spend. I think that most of us would agree that the money should be spent where it will do the most good and silly AC outlets and silly cable elevators are definitely not it. 
I would hazard a guess that most educated audiophiles believe the same.
The difference between myself and them is I do not have a shred of political correctness in me and I will not pacify those that would have other people wasting their money on mythological garbage. 
The second most dangerous person in existence when it comes to spending other peoples money is an audiophile who thinks they can "hear."  The first is any politician. 
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