What type of wire for dedicated 20A AC lines?


I’m about to have two 20A dedicated lines installed. What type of wire should I use? I know there are differences of opinion on whether to use 10 AWG or 12 AWG, however the link below makes a great case for using even 8 AWG solid core copper on longer runs like mine will be (50 ft), to ensure a lower resistance, lower voltage drop over the long run, and therefore more access to instantaneous current for my Gryphon Diablo 300. The wire would need to be stepped down to 10 AWG to connect with the receptacle. The article actually states that the thickness of the wire is more important than the fact that it is dedicated…

Assuming I want to follow this advice, which again makes sense to me, where would I find such wire to give to my electrician?

 

nyev

Most of what is published about increasing ampacity is rubbish. Joe AudioPhool installs his hifi in the last socket in a room with daisy chained quick connects. Then installs a direct big ass line and writes about it. The real problem is the daisy chained quick connects. My 10 year old home had a ≈5v no load drop across a dozen q/c on about 75 foot run. All quick connects removed and same, cleaned wire attached to screw terminals. Drop? 0.5v. Same problem exists in older homes with old worn and oxidized sockets.

 

See http://ielogical.com/Audio/CableSnakeOil.php#ACWiring for all the difference big ass wire will make. What AudioPhools don’t ever seem to comprehend is the peak amplifier current is supplied by the power supply, not the A/C line. Musical peaks are completely asynchronous to the AC line Hz. A 15A breaker can supply about 45A for a couple seconds, long enough to fry your amp and speakers. See https://www.c3controls.com/white-paper/understanding-trip-curves/

See?  Tons of opposing but well-informed opinions whenever this topic comes up!  So weird that gauge of wire could be such a polarizing topic.

There are so many variables that I’m not sure the physics can fully inform the nature of sonic effects of gear.  For certain cabling, including power cords, I can blindly identify which cable is connected when comparing between two cables.  And more expensive doesn’t mean better.  I recently discovered that the generic USB cable that came with my USB reclocker sounds better than the AudioQuest Diamond USB - go figure (AQ Diamond sounds better when connecting my streamer directly to the DAC and bypassing my reclocker however). Didn’t mean for this thread to go down that path, but oh well!

Again, it’s not as if it’s a big cost to get my electrician to go to 10AWG, so if I’m going through all this trouble, that relatively tiny cost in case it does help is definitely worth it.  Peace of mind.  Boy people seem to be passionate about shooting down any need for 10 AWG!  I wonder why that is.
 

 

Again, it’s not as if it’s a big cost to get my electrician to go to 10AWG, so if I’m going through all this trouble, that relatively tiny cost in case it does help is definitely worth it.  Peace of mind.  Boy people seem to be passionate about shooting down any need for 10 AWG!  I wonder why that is.

I agree!

@nyev 

as i said before, i got a 10-2 dedicated 20 amp line using atkore 10-2 cable. It is very well made cable steel sheathed. 750 for 250 foot line. They only sell in 250 feet. I have 125 left. I also run my best power cable from the dedicated outlet to my QB8 ( that cable is extremely important). Then every component plugs into the qb8. Its really not hard. It yielded great results. Everything was to code. I just followed the advice of someone who sets up systems all over the world and at high end audio shows. He just set up a huge room in Munich. Pretty sure he knows what he is talking about.

Post removed 

@dancarlson10 , that is great that your QB-8 approach worked so well for you. I am really hoping that approach will work for me.  AC line conditions and other variables (like how many houses are serviced by a public transformer) will vary from house to house and system to system, so what works best for you may not work for me.  I’d say if I’m lucky I will arrive at your solution, since the QB8 will have the least coloration of the sound vs conditioners.

Nordost told me that you can’t even judge a particular conditioner’s effect or lack of effect on tonal balance as a generalization, because the effect on tonal balance, if any, is entirely system dependent.  So what works for one person may not work for another, given all the variables.

 

@nyev 

 

of course. My point was not at all about the qb8. Whatever conditioner you get will help. I was mainly referring to the dedicated line. Once you do that, your noise issues will settle down. You won’t care as much about the conditioner. Just have the electrician test the noise. We got .01, which is hopefully something close to what you can get. Also the outside world is just quieter after midnight. Its not just noise coming through the system. I am in a big city and the dedicated line helped a ton. I am sure it will for you also assuming you can run one to code. Just get a nice cable to run and Dont bend it. Have the electrician run it in a way that is clean. You will be fine. Cheers!

@dancarlson10 , really hoping I get that same result with my dedicated lines and I care less about the conditioners after it!  I’m so looking forward to it….  As I said above my dealer said “you won’t know what hit you”, and it’s not like he gets a sale out of it.  Well, he gets to sell me two Shunyata wall receptacles for $300 but he didn’t know that at the time (and still doesn’t…).  I was going to wait for the electrician to provide the quote and be good with the plan, but I think I’ll take a small risk and order them now so there is less of a delay!

 

+1 What andybflo said. I’m laughing with you.

As an electrician and electronics technician(industrial controls) since 1979 there seems to be limited knowledge regarding the relationship between voltage and current flow(amperage) I=V/R and powerP=V*R. In the situation of voltage drop, lets consider a home that is 5000sq ft that’s 100x50 ft. The longest wire pull might be 120ft. Take the nameplate current draw (for the 120V supply) on any 150W integrated amp and plug those numbers into any of the voltage drop calculators available online and voltage drop is a non factor. It is also true that devices designed to plug into general purpose outlets cannot exceed 15amps.  also correct regarding . If someone’s system sounds better to them with larger wire then by all means enjoy.

poppsg

No connected load on the branch circuit and you measured a 5V VD on the end of line.

Yes. The lame ass electrician stripped the wire when pulled. The plaster & painter didn’t cover the boxes and the wire barely made connection is some places.

About 45 years ago my mother-in-law’s house barely escaped a fire when the same sh!tttily done aluminum wiring nearly set the receptacle alight.

 

Where was your reference point used for the measurement? At the electrical panel?

Where else?

 

What type of volt meter did you use?

calibrated Fluke.

 

I’ve been fixing wiring for my HiFi for 50 years. There are all kinds of idiotic claims being made. Few know that plain old Romex beats fancy wiring in a conduit. See Microsoft PowerPoint - Indy AES 2012 Seminar w-Notes v1-0.ppt (wordpress.com) by Bill Whitlock. The paper addresses N O I S E while audiophools prattle on about current which is a non-issue in a properly wired installation. We ran over two kilowatts of amp power on a single 20A breaker. Never blew once. Adding additional loop area is just plain  D U M B !

@poppsg , yes Ohm’s law absolutely comes into play here! I remember those formulas back from school; I really got into that stuff. I’m by no means an expert. I will call you on “It is also true that devices designed to plug into general purpose outlets cannot exceed 15amps.” which isn’t accurate when referring to momentary “peak current” or “instantaneous current” which can go up to 70A for milliseconds at a time. Again, I’m no expert, but I think this is pretty widely understood when it comes to amplifiers!

70A into 8Ω is 39.2KW. Ain't never gonna happen in a power amp.

200W into 8Ω is 5A @ 40V. Even a 3x peak is only going to draw about 5A from the line for a fraction of cycle.

2x200W amp might take from mains close to 1kW during peaks. The problem is that peak supply current won’t be expected 8A, but rather close to 40A. It is because current is drawn only for very short time (millisecond pulse) at the peak of full wave rectified sinewave. It applies to most of LPS. Power delivered with such short pulses not only creates larger voltage drops in house wiring, but also heat-up amp’s power transformer, that has to be oversized (higher copper losses and higher core losses for eddy currents and hysteresis).

 

 

jea48 said:

Where was your reference point used for the measurement? At the electrical panel?

ieales response:

Where else?

Usually the no load voltage is checked at the last outlet on the branch circuit. No loads are connected to the circuit. If a difference of potential, voltage is present it will be the same as the applied voltage at the feed end. In this case the branch circuit breaker to neutral bar voltage.  If 120V at the panel it will measure 120V at the end of the branch circuit that has no load connected to it. (Add load and then measure again for VD.)

Why? Simple Ohms law. You need a load to have a VD. No load no VD. The internal resistance of a typical DMM is about 10M ohm. 

     jea48 said:

What type of volt meter did you use?

ieales response:

calibrated Fluke.

10M ohm internal resistance. 120V / 10M ohm = 0.000012 amp.

 

Jim

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@kijanki

+1

 

Please explain what happens if the power transformer’s secondary winding voltage is lower feeding the rectifier, due to a quick AC mains VD event, and the electrolytic capacitors voltage is higher. Just going from memory the rectifier will not conduct and the caps do not get recharged for that "(millisecond pulse)" in time.

 

Jim

I recently installed a dedicated 20 amp, 8 gauge multi-strand run.  The run is 123 feet in length first going to a 30 amp locking plug (that goes to my surge protector) within the entertainment console then an additional 2 feet to a pair of 20-amp, hospital-grade plugs at the termination outside of the console.

The 8-gauge wire is maintained all the way from the panel to the three outlets (including the hospital-grade recepticles) and there are no junction boxes along the way.

And just because I had it, I put a big ferrite bead over the wire where it comes out of the panel.

This cleaned up a bunch of "hash" on my Yamaha SACD, but less so on my Oppo95, which has a better power supply.

@jea48   You are right - there will be no current thru rectifiers until capacitor voltage will drop below rectifier supplied peak voltage.  Theoretically it is possible to build LPS where capacitors keep average instead of peak voltage, but it requires huge inductor in series (in order of Henries) made with thick wire and AFAIK nobody is doing it.  One problem is lower rail voltage (average instead of peak) while the other is dependency on the load current.

http://www.r-type.org/articles/art-144.htm

This stuff is awesome and I barely comprehend the explanations, but it sounds like there are strong arguments that I’m going to really going to enjoy my big fat 10AWG wires with lower resistance, enabling more rapid access to glorious peak current, all for like two hundred bucks extra, give or take. And if the anti 10-gauge crew end up being right and it does nothing, the extra bucks will totally still be worth it knowing those big fat wires are providing the juice!  Can’t go wrong.

 

There is more to it than just adding a 10 awg wire.  I design electrical infrastructure to support audiophiles homes as well as manufacture premium panelboards.  I have a pretty dense 6 page specification on how to assemble it all.

FWIW, if your going through the trouble of adding a line, add 2 to 4.  Its not much more money and you will hear the difference. 

@kingrex

I’ve read different opinions on running all gear in system through single 20A line versus multiple. I don’t know enough to have an opinion myself yet on this.

 

If someone were to install three 20A lines for a single 2ch system, let’s say, how should they determine the components to be driven by each line? Let’s say system has 2 monoblock amps, a preamp, a digital system (e.g., dac, streamer/server, sacd player, maybe external clock), an analog system (TT, phono pre). What goes to each of the three lines? or two lines?

FWIW, if your going through the trouble of adding a line, add 2 to 4. Its not much more money and you will hear the difference.

I agree! I installed four dedicated lines one for each mono block amp, one for digital and one for analog.

Mike

So here's a beginner's question.

If you're putting in a dedicated 20amp line, or even 2 or 4 of them, and if there are no free spaces on the main breaker box panel that you currently have, do you also end up putting in a new larger panel?  Does a sub-panel solve that?  And what are the other upsides/downsides of a sub-panel?

@ditusa , yes I was planning on installing two lines, and then playing around with what configuration sounds the best.

For others to reference, I’ve read it’s important to have all of your lines on the same electrical phase.  The electrician will know how to do this with your breaker panel, but probably won’t know to do it without being directed.

@nyev,

I’ve read it’s important to have all of your lines on the same electrical phase. The electrician will know how to do this with your breaker panel, but probably won’t know to do it without being directed.

I agree!

FWIW: My four dedicated lines are not on the same electrical phase at the breaker panel. The best sounding configuration in my rig is what I posted above.

Mike

 

OP,

I think you have made a good choice… I put in another direct line last year. I had the electrician use 10 gauge romex. It made a nice difference.
 

I think it is important to move on these things one at a time… make each prove they were worth it. There are so many possible improvements, each can be a learning experience. Go hog wild when the last three things you did to your power really impressed you and you are now convinced major surgery will produce further gains. 

@nyev :

I’m going to really going to enjoy my big fat 10AWG wires with lower resistance, enabling more rapid access to glorious peak current, all for like two hundred bucks extra, give or take. 

Good decision. Best of luck with the project and install. IMO, the peace of mind alone by doing 10 AWG, no regrets down the road, is totally worth the extra two hundred bucks, regardless of whether it makes a difference in theory or practice 

 

Here’s a question about the work my electrician is about to do: is there any creative way I can isolate the AC noise that our tenants generate from our lines?

Our tenants have their own breaker panel that is fed off of our breaker panel. Someone above suggested a particular filter device to deal with noise coming into the whole house. My fear however is that this could do something to the tonal balance that I’d be stuck with. Filters can do that. But, I was wondering if such a device could isolate our AC lines from our tenants, on the tenant’s side of the breaker so it doesn’t impact our lines?

Or maybe there is another way to isolate their AC from ours?

 

Post removed 

Thanks for all the entertainment, guys.

Now, I will go read one of those "cable" threads.

 

This stuff is a laugh riot.

Cheers!

 

 

I used an armored 10 GA for about a 50 ft run.  From time to time I monitor my power draw and  I rarely see usage of more than 350 watts on my PS Audio P20 meters listening at 85 db or so.  I would think 10 ga would be just fine.  

Code in most locations will specify an "arc fault" breaker on a 20a circuit.  In my rig, this has caused headaches as the breakers occasionally trip on dynamic passages. I have 2 dedicated, short run 20a feeds direct from breaker box at service entrance, feeding system with McIntosh MC462 and MC257 power amps and multiple powered subs. 

@richopp

An Overview of Audio System Grounding and Interfacing

Take note of page 16.

Read pages 31 thru 36.

Note the chart on page 35. AL armored MC measured the second best. Number one being the best where the hot and neutral conductors are twisted together the entire length of the branch circuit. The EGC is ran along side the twisted pair.

.

LMAO! That keeps you up at night huh? 2 AWG solid silver with 2.8 % copper.outer layer...fantastic...Ill sell ya some.....geeeez

Someone earlier mentioned mains feed heat buildup. So I measure it.

My system is 715 wpc fed from a single 20A /12ga cct. Three bottle rocket amps account for 25% of the power, so average draw is larger than if all SS. Class A would be worse, but Class A power transformers negate the issue as we shall see.

After three hours of robust pop program, temperature rise on the 12ga cct was 2.9°C measured inside the yellow sheath with a T thermcouple. The really bad news is that over the 20 foot run, the resistance increase is a whopping 51mΩ or 0.051Ω for the non-technical types. This is added to the 20°C value of 32mΩ. The good news is the power transformer internal resistance also rises 1 - 2% or much more than the line feeding it. Calculated improvement in self-heating for 10ga is about 30mΩ, less than the PT and less than the connections from the power line to the transformer winding!

For those posting fancy graphs of diode current, those are steady state loads. Music current draw bears no relation to those graphs.

Spend all the money you want on overkill wiring. It will do no more for the sonics than a fancy faceplate or blue LEDs.

Sonic improvements can be achieved by ensuring that all connections from the utility input to amplifiers are pristine. Inspect and cycle all power plugs every six months.

FWIW, the 10 gauge dedicated orange romex line purchased at Home Depot and run from a 20 amp breaker to a 20 amp medical grade outlet sounds better with my gear plugged into it than the 12 gauge non-dedicated line right next to it on the wall with a "deluxe" but non-medical grade outlet.  The difference is not subtle.  I plug my amp directly into the green dot outlet, all other gear goes through the same outlet via a power conditioner.  If I had not installed the 10 gauge line while I had the wall open, I would have always wondered if I had made a mistake.  Now, in practice I have absolutely no regrets, although in theory some of you apparently believe I should be sad I spent the extra money and wrestled the stiffer wire.  YMMV.

kn

Good intentions and bad information about having 2 20amp 120v dedicated circuits & outlets will create a massive ground loop and hum.  A 15amp 120v outlet will generally suffice for 2 channel home audio. 

If you must add a dedicated 20 amp 120v circuit/outlet in your room....use the following: 1) compatible 20amp 120v breaker for your service panel 2) 12 ga Romex 2 conductor w/ ground 3) 20 amp 120v outlet. Do not increase the wire size beyond 12 ga. as this is a code violation and will not give you better ac quality or quantity.

You should use a large quality 15amp or 20 amp multi-outlet strip with enough outlets to plug everything you require into it.  If that is impractical then use identical smaller outlet strips piggy-backed into one another. I have great success using 2 identical Furman  6 outlet 15 amp rated outlet strips.

You can pm me for more advanced instructions to make your system as quiet as possible.

 

Do not increase the wire size beyond 12 ga. as this is a code violation

Not true...

FWIW:

National Electrical Code 90.1 Purpose:

(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons.

(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

 

NEC could care less how your audio system sounds. It could care less if you have ground loop hum. No where in the code is it mandated voltage drop shall be a consideration . NEC is bare minimum electrical safety standards.

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12 gauge non-dedicated line

A non-dedicated line is [almost] always a bad idea. Refrigerators, hair-dryers, SMPS, light dimmers, etc. add nasty stuff that some products cannot tolerate.

When we built recording studios, the gear and the garbage were often on separate services to the street! One well-heeled owner installed 100% system isolation via battery. IIRC, Sony NYC had its own gen set in the basement.

I just completed my 50 foot dedicated AC.

Your question was what wire to use.

I believe I addressed this issue with about the best wire available.

Oyaide high quality copper three wire 10 gauge.

This very special cable is available through the US distributor, www,lotusgroupusa dot com. Joe Cohen in NorCal. 
This cable is very close to a good quality power cord. Its construction includes 2 copper grounds in addition to the main three wires. 1 a ribbon that wraps around the main 3 and a second one in a thin copper braided wire.

To get the best, one has to pay. My 50 feet cost $4K. In addition I terminated the run with two Oyaide duplexes and carbon fiber face plates. This was $1200 more.

And my electrician was another $2200. My run was complex through the attic.

Was $7400 worth it? You bet! The improvement was global. I got about a 25% better system. Clean, punchy, stunningly real!

The only catch is that none of this Oyaide stuff is UL approved. But the Japanese standard are way beyond those in the States. And I did not touch the house AC system. Still, you have to find a licensed electrician who is willing to deal with non UL. I went through a couple and luckily found a guy willing to do the install.

And I had to pay him a consultant fee to talk with Joe Cohen on how to deal with the unique Oyaide cable.

The main issue is wire. For me, there is only one.

 

It would have been really sweet to run a parallel 10ga Romex and charge for  tickets to demos of the improvement...

@jea48  Look, I don't know how old any of poster's houses are or if they are wired with cloth-covered wire or built in 1930 or whatever, and I am sure there are reasons that exist for some upgrades, etc. in some situations. 

Also, if you think running a "dedicated" wire of some specific material to your home stereo will help it sound more like a live concert hall experience, who am I to tell you it doesn't?  Or adding a voltage regulator or whatever else your electrician tells you to do. 

I guess if I had a pair of Audio Research Reference 750 SEL amps, I might be tempted to look into the power requirements from my panel to the amps.  What happens BEFORE the panel, well, I guess calling FPL down here would get me lots of help (laughing--they don't actually talk to customers).

However, as a former dealer, I can tell you that every electron I ever interviewed was non-committal about their traveling preferences along signal or power wires, so I can only base my POV on that.  Same for "directional" patch cords made out of elemental silver or titanium with solid gold ends...OK, gold ends do make a  difference in corrosion...that cost $100,000/meter are wonderful for bringing out that 3rd chair violin, I am sure.

Whatever brings that orchestra into your listing room is fine with me,I guess.  I wonder what the rock bands require power-wise in the auditorium where their concerts are recorded live?  Not that the recordings are "managed" before they are released, of course...

Cheers!

If the UL listed "whatever your plugging in" draws less than 20 amps 12/2 is great. There will be no voltage leakage from a 50 foot run, 500 feet maybe. It depends on what else is on the circuit Since these are dedicated circuits there is no need to worry about enough amperage or voltage. Cleeds you are wayyyy off base. Whether it is 12 awg THHN in a conduit or 12/2 Romex doesn't matter. If it is a 20amp circuit, 12/2 always meets NEC Code.

To chime in on an update.  I’ve since engaged @kingrex ’s services to spec out my AC lines and other fixes for my electrician to follow.  Rex has been doing this for years and as he said above, I’ve since learned that it goes way, way beyond just the gauge of the wire…

Here is what Michael Fremer of Stereophile said about Rex working with Garth Powell of Audioquest, when they and others joined forces to resolve Michael Fremer’s AC issues:

 

 

Motivated by the comments here in favor of having a dedicated line for audio, I decided to install 2 in my music room, 10AWG 20A each.
I ask if it is necessary to run a Burn-in period.