AC Power Question


I am repositioning my system and need to install ac outlets. I assume its a good idea to have a dedicated circuit for my system below ( stereo only). Should i have 2 dedicated circuits? 15 or 20 amps? I may also have a power conditioner in the loop as well. Thanks in advance for any thoughts and advice on do's and don'ts.... 

CJ 16LSII preamp
Levinson 532H amp
BW 803D3
Roon Nucleus server
Mytek dac
SACD player
Basis turntable
Heed phono pre
Large screen TV
Apple TV
Cable box
WiFi router



Ag insider logo xs@2xepatrowicz
The cost difference assuming you have the breaker space for it is almost zero, so go for 2 x 20.  This requires only 1 more conductor.

You can underrate, which is a little safer. Choose 15 A breakers, but 12 gauge wiring. You get the low resistance of the thicker copper, but the safety of the lower tripping point.

Also, you may need a cable TV ground isolator. Might as well get one, they're cheap and prevent ground loop issues later.
Correct me if I'm wrong but if using two runs off two breakers, make sure they are on the same phase or you could get noise. I used 8 gauge on a 20amp breaker.

noromance
"if using two runs off two breakers, make sure they are on the same phase or you could get noise"

That is myth, fiction, and misinformation there is no truth, validity, or basis for this claim where do you think the "noise" will come from!
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@jea48 and @almarg are the experts on this subject. Hopefully one of them will join in.

They advised me when installing my dedicated lines. I'm running my analogue and digital on separate dedicated 20 amp circuits into separate Hubble duplex receptacles. In my case, I have a subpanel for my audio lines.

Both lines on the same leg with equal distribution of current draw from devices and appliances
to the sevice panel. 


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The load placed on each of Lowrider57’s circuits is minimal and relatively steady. Placing both on the same leg is good practice based on the application. If you think you’re going to have a perfectly balanced panel just by arbitrarily splitting loads, you are in fantasy land. The only way to balance a panel is by doing measurements, and even then at one instant the balance will be different than the next. 
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clearthink599 posts01-23-2019 2:56pm


noromance"if using two runs off two breakers, make sure they are on the same phase or you could get noise"

That is myth, fiction, and misinformation there is no truth, validity, or basis for this claim where do you think the "noise" will come from!


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almarg8,594 posts05-16-2013 9:59am

Regarding the issue of splitting the load between two AC phases, as is usually the case I am in complete agreement with Jim (and Foster_9 and Pbnaudio who expressed similar positions), at least in situations where the AC draw of the system is not unusually large.

I looked through the ExactPower paper Jim referenced, the relevance of which is captured in its subtitle, "A practical guide for AV designers, installers, and electricians."

As an EE with extensive background designing analog and digital circuits (not for audio) I find the paper to be authoritative and credible. Which is to be expected, considering its authors. Among them, Henry Ott (biography here), is a world renowned authority on numerous aspects of electrical and electronic design. Bill Whitlock (biography here) is certainly no slouch either. Some excerpts from their paper:
Less than 300 microamps of ground loop current can cause hum as it flows in an unbalanced audio interconnect cable. However, harmonics of 60Hz that are generated from lighting dimmers or switch-mode power supplies sound like �Buzzz� mixed with a bit of �Hummm� and are more easily coupled by even smaller currents. Harmonics can add together when equipment is powered from different phases, so clearly there is an advantage to specifying same-phase electrical service to power the electronics systems in most cases....

Any leakage currents on the safety ground wires of split single phase load circuits fed by different phase legs will add together due to the 240V potential difference....

Power conditioners do not solve any of these common problems: Cross phase coupling (doubles hums & buzzes) .... What actually does solve them: Same phase power.
Also, regarding ground loops, I would commend this paper by Bill Whitlock to everyone’s attention, particularly the first page. It seems to me that if leakage current finding its way to the chassis (and safety ground) of a given component, via stray capacitance in the power transformer, EMI/RFI filters, etc., is out of phase with leakage current in another component that it is interconnected with, inter-chassis current flow between the two components, and therefore susceptibility to ground loop-related hum and noise, will have been maximized.

Regards,
-- Al
https://forum.audiogon.com/discussions/dedicated-power-lines  

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

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Al, (almarg), just does a better job of explaining things.

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Cheers,
Jim



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The electrician and the audiophile. Apart from safety and codes - obviously important to both parties - will never be in agreement about what happens to sensitive audio gear at the microvolt level. #sameleg
Being an Electronics Engineer, I live in both sides of this equation. Take this example:

Builders do the dumbest things you can imagine, which further compounds issues. For example, my 3000 sq ft house has a second floor laundry near the front of the house, and the breaker panel is in the basement on the opposite side near the back. In their infinite wisdom, they ran 14/3 Romex for the circuit that powers the clothes washing machine, which is some 130 feet long. The punch line is this: they used the other leg on that 14/3 for lighting in the first floor. Every time the clothes washer was running and switched cycles, the lights would flare. No wonder they would burn out so often, with all that excess back-current! I fixed the problem by running a new 14/2 circuit just for the lighting, and one day, when I feel more motivated, I’ll run a new 12/2 for the 15 amp circuit feeding that clothes washer. 


I think dedicated, de-rated, 20A lines are the way to go. If you think you might need two lines, then get three. If you think you need three, get four. It’s less expensive and invasive to do it all at once.

I am also a major believer in getting an electrical construction permit before commencing work. Your local electrical inspector is your inexpensive QC against shoddy work - we’ve seen examples of that here on Audiogon - or a simple error. And the approved permits can be useful when you it’s time to sell your house.

I have dedicated lines on both legs of my service, and don’t see or hear a difference between them. YMMV. My system benefits from isolation transformers and power conditioning all around, including on amplifiers. They make a huge difference, and all for the better.

While you’re doing this work, it’s wise to check the other aspects of your power. Are all connections clean and tight? Is your grounding up to current code? And here’s the most overlooked detail, imo: Can your electric utility deliver sufficient current? If you think your "200A service" means that your utility can deliver 200A of current, you are almost certainly mistaken. Do your lights dim substantially when you turn on your power amp? That can be a clue to current delivery issues.
sleepwalker65
... they used the other leg on that 14/3 for lighting in the first floor. Every time the clothes washer was running and switched cycles, the lights would flare. No wonder they would burn out so often, with all that excess back-current!
Will you please explain what "back-current" is? If you have a 14-3 cable, then each of the hot wires come from different legs of your service, correct? (After all, that's why they can share a neutral.) Please explain how a changing load on one leg can influence the voltage on the other leg.

If your 14-3 cable is connected to the same phase (leg) of your AC service, that's a code violation because of the shared neutral, no?
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@mental , Before I had work done, i inquired on a thread and @jea48 participated with excellent instructions on the optimal setup of mains power to an audio system. @almarg joined the conversation and as always I valued his input.
After the installation of a subpanel hosting 2 dedicated lines on the same phase and an added ground rod, with Romex wired independently to separate Hubbell duplexes which are grounded back to the service panel. I came back to the thread to review with jea48.
Jea48 asked me specific questions regarding the hot, neutral, and ground. I actually called my electrician to get the correct facts, presented them to the forum, and was told it was done correctly.
It’s one of the best upgrades added to my system.

Same leg means same phase and you just caused an imbalance at the main panel.
The load from the audio lines is minimal. I asked the electrician to balance the load to both legs at the panel. He did a ampere calculation and moved some breakers to balance the current demand on the two legs; eg, refrigerator on leg A, air conditioner on leg B. Washer leg A, dryer leg B. Furnace 60A breaker shared, Subpanel 60A breaker shared.

2 phase panel 60A total.
60A subpanel.


Forget dedicated lines and simply get  Goal Zero Yeti lithium power station - anywhere from 1000w to 3000w depending on your needs.  The cleanest power.
No need for fancy conditioners, cables or anyting.
Simply 
https://solargenerator.guide/goalzero-3000-lithium-solar-generator-review/
An interesting product that I've only reciently heard about. I would be interested in reading some Audio reviews regarding it. Also interested in how many years the lithium batteries last and the replacement cost.
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@cleeds 

Will you please explain what "back-current" is? If you have a 14-3 cable, then each of the hot wires come from different legs of your service, correct? (After all, that's why they can share a neutral.) Please explain how a changing load on one leg can influence the voltage on the other leg.

If your 14-3 cable is connected to the same phase (leg) of your AC service, that's a code violation because of the shared neutral, no?

On a shared neutral such as 14/3, the back current is reverse flow from the red leg affecting the neutral potential for the black leg and vice-versa. That’s why shared neutral circuits sometimes use a smaller gauge neutral conductor. When both sides are steady loads, such as lighting, you can do shared neutral, but in the case of the circuit powering my clothes washer, the other leg powered a lighting circuit, which caused the lights to flare when the washing machine was changing cycles and electrical demand from it surged. 

Shared neutral circuits must never have both hot conductors on the same leg of breaker panel. That would cause the neutral load to reach double the current rating, and create fire hazard. Shared neutral should be against code in my opinion. The correct use for 14/3, 12/3, 10/3 etc... is 240 volt loads that require a neutral conductor, or sub panels. 
As my questions should suggest, I understand how these circuits work. What I don’t understand is how the load on one phase can influence the current on the other phase, unless there is something wrong with the electric service in the first place.

Shared neutrals are absolutely allowed under NEC and I see no reason to avoid them.
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cleeds1,945 posts01-25-2019 7:08am

As my questions should suggest, I understand how these circuits work. What I don’t understand is how the load on one phase can influence the current on the other phase, unless there is something wrong with the electric service in the first place.

Shared neutrals are absolutely allowed under NEC and I see no reason to avoid them

The load on one Hot Line does not affect the load on the other Hot Line. What can be affected is the voltage measured from the hot to neutral due to a severely unbalanced multiwire branch circuit due to voltage drop on the heavily loaded hot to neutral circuit. The shared neutral is part of the circuit.

sleepwalker65 stated in his post a 14-3 w/grd 3 wire multiwire branch circuit feeds the laundry room outlet on the 2nd for the washing machine and a ceiling lighting circuit. (One Hot Line for the wall receptacle for the washing machine, the other Hot Line for a ceiling lighting circuit). The electrical panel is located in the basement on the opposite end of the house. How long, distance, is the multiwire branch circuit?

(First this must really be an old house. For as long as I can remember the circuit for a (laundry area) cloths washing machine per NEC is 20 amp, #12awg minimum copper wire.) A muliwire branch circuit should have never been used in this instance. Does it meet bare minimum NEC code ? Yes..... I wouldn’t have though......

So back to the load on the Hot Line to neutral load created by the washing machine. Say the distance from the electrical panel to the wall outlet for the washing machine is over 100ft, or more. (It could very well be. 3000 sq ft house.) What do you think is happening to the current draw of the motor during the wash cycle? Do you think it is steady or fluctuating? As the current is fluctuating what is the voltage doing on the circuit? I bet it is also fluctuating due to Voltage drop on the line created by the load on the motor in the wash cycle.

If a clamp on amprobe was clamp on the neutral at the end of the 14-3 where it splits off to 2 two wire circuits, (one for the washing machine, the other for the lighting), you will see the varying amperes of the motor load. If you measure the voltage from either Hot Line to the common neutral you will also see the voltage fluctuating. If the ceiling lights are incandescent bulbs you will see the voltage fluctuations caused by the voltage drop on the neutral wire.

As for light bulbs burning out faster than they should normally, I would be looking for a loose or corroded neutral connection starting at the electrical panel neutral bar connection to the junction where the circuits split off the 14-3.

Also worth mentioning Motors are rated in HP. As the voltage drops due to voltage drop current goes up. More current more heat. Too much heat will cause terminations to overheat, corrode, and can eventually cause them to fail.

As for the use of multiwire branch circuits. They have been around ever since 3PH 4 wire polyphase and split phase single phase distribution power transformers. Common place especially in office buildings and industrial facilities.
They save/saved money. Less wire and fewer conduits and smaller sized conduits. Less labor cost man hours.

Then came the age of computers. Starting in the 1980s data centers in office buildings. PCs, (Personal Computers), started showing up on workers desks connected to the main frame. 1990s even more PCs on workers desks. Around the early 2000s problems were starting to show up. All the while, more PCs were being installed in office buildings. Electricians were being called to trouble shoot electrical problems on 4 wire multiwire branch circuits. What they found was the neutral conductor at the electrical panel connection to the neutral bar was corroded, burnt, and the insulation on the wired was discolored and in some cases burned near the termination. HARMONICS! All them PCs.

The solution to the problem? Increase the size of the neutral one size larger than the phase conductors. So if the phase conductors are # 12 the neutral conductor is #10. Did that work? Yeah, for the branch circuit wiring........

Then come the 2008 NEC code edition. Something new for multi wire branch. For electrical safety reasons all ungrounded conductors of multi wire branch circuits shall be required to have all ungrounded conductors of the multi wire branch circuit to be de-energized simultaneously. Either a multi pole breaker or if single pole breakers are used an approved common tie device must be used that opens all breakers with one movement. What do you think this did for the benefit of using multiwire branch circuits in office buildings build after the 2008 NEC was adopted by AHJs across the US? (For many years there were, still may be some, AHJs that did not adopt this section of the 2008 NEC. My State did in Jan of 2009)

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My situation is a 15yr old house governed by Canadian electrical code, which is for the most part consistent with the US NEC. The reason the builder used 14/3 for those branch circuits was purely economics based. In Canadian electrical code, a clothes washer circuit is only required to be 15 amp. Should it be on its own? - yes! Should it be 12/2 instead? - yes! But, the reality is this house was built in a large development project, and they didn’t do things to meet ideals, they based every decision on the bottom line. One fine day, I will get around to running a dedicated 12/2 for that clothes washer. As an intermediate stage, I removed the lighting circuit from the other leg of that 14/3 and put it on a dedicated 14/2, which has improved the lifespan of lightbulbs. 
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I use Acoustic Revive EE 2.6 solid copper 10g. in wall cable to Furutech GTX R NCF outlets for the digital front end, preamp & amp each have there own seperate 8 g. solid core copper to Furutech GTX R NCF outlets, this is a huge improvement over standard Rominex 10g. stranded wire especially with the amp and preamp having there own separate dedicated lines.
tecknik151 posts01-25-2019 8:13pm

I use Acoustic Revive EE 2.6 solid copper 10g. in wall cable

I don’t think that cable could be used in the USA for in wall branch circuit wiring. Is the cable NRTL safety testing Listed? Such as UL?
https://www.osha.gov/dts/otpca/nrtl/nrtl_faq.html

Acoustic Revive EE 2.6 solid copper 10g. in wall cable
https://www.ebay.com/itm/Acoustic-Revive-EE-F-S-2-6-mm-PC-TripleC-power-cable-2-00m-NEW-/17365209792...

this is a huge improvement over standard Rominex 10g. stranded wire
I couldn’t find anything on " Rominex 10g. stranded wire".
Here in the US we have Romex 10ga solid copper wire.
(Romex is a registered Trade Mark Name product of NM sheathed cable.) (NM, Non Metallic)
https://www.homedepot.com/p/Southwire-By-the-Foot-10-2-Solid-Romex-SIMpull-CU-NM-B-W-G-Wire-28829099...
jea48

I don't know if its NRTL tested or if it can be used in the US, Ive been living in Vietnam for 8 years now, I left the states 22 years ago and have no idea whats allowed or not allowed as far has electrical code.

The ebey link does not show the proper EE 2.6, ( I only see two internal wires)  all the EE 2.6 I have seen or purchased came with three internal wires, neg,pos, grnd.

I meant Romex, I think 10g solid is fine for digital gear but for analog 8g. solid made a noticeable improvement.
Just got my electrical inspection a few days ago. Inspector kept asking me why I put in 10 gage wire and an outlet that didnt cost 1.49

I put in a dedicated 20A line that feeds a P15 regenerator. With everything running I'm not even pulling 5A. 

I can't speak high enough about the monumental change the regenerator made to my system
Its amazing how this simple subject always gets bogged down in complexity and code and comments, usually from people who've never done and so don't know what they're talking about. I've actually had the standard normal house wiring, and then run a dedicated circuit, and then run an even better dedicated 240v to a step down transformer. Say again, I've actually done the wiring and listened and compared.

Your best cost option is to put everything on one single circuit, conservatively rated. i.e. use 20A even if you could get by code with 15. Do not run two circuits. If you do then put all your audio on one, all non-audio (record cleaner, lights, etc) on the other. As someone correctly noted it takes only a very tiny difference in ground potential to produce hum. Again, I know for a fact and from experience you can and will get hum when different components connected to different circuits are connected together. Different manufacturers follow different construction so that what looks the same is not. i.e. just because you see a ground plug does not mean the manufacturer connected those pins with a wire! So you may sometimes get away with it. Or you may just give yourself a headache.

One circuit. KISS. Capiche?
+1 @millercarbon 
I tried initially using two runs and ran into hum issues. Now I use one run of 8 gauge on a 20A breaker into a Hubbell L20R/L20P.
noromance1,688 posts01-28-2019 7:29am

+1 @millercarbon
I tried initially using two runs and ran into hum issues. Now I use one run of 8 gauge on a 20A breaker into a Hubbell L20R/L20P.

The problem could be with your equipment. Anything is possible.... Or it could have been the type of wiring and wiring method you used.

As for the use of multiple dedicated branch circuits to fed audio equipment, that is connected together by wire interconnects, it’s done all the time without any ground loop hum problems. Again when the type of wiring used, and the wiring method used for the installation of the branch circuits is done correctly. And that includes long branch circuit runs.


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