Dedicated Power Lines


Been thinking about running dedicated Romex circuits from my circuit breaker box for my rig. No . . . I decline paying for specialty wire, Romex will do. The question is how many discreet lines and the amp capability of each line. I'm still trying to figure out how to do the installation in accordance with Code, without tearing my finished basement apart. For that, I'll consult a licensed electrician.

My rig consists of the following gear: (1) self powered sub that is rated at 1500 "Class D" watts; 4500 watts on a surge; (2) ARC tube CDP; (3) ARC tube line stage; (4) ARC tube power amp rated at 120 wpc - supposedly draws 700-800 watts when driven hard; (5) ARC tube phono pre; and VPI TT. I have a large screen plasma TV and a DVD player. I think that stuff can run off the house circuits.

Right now, everything I just listed is sucking juice off the same line. I gotta believe no good is coming from that set-up. Funny story -- one day my kid was playing Rosetta. I think it's a band that plays music, or at least that what my kid says. Tons of bass. When the band kicked into "low gear," first the basement lights dimmed, then the circuit breaker tripped.

Oh, my house is tied into the utility lines with a 100 amp service. If I change that out, that's the next project. But not right now. Other than Rosetta, no other power delivery problems noted.

Thanks
bifwynne
Add a 40 amp sub box next to your service. Add in a whole house surge protector (you still need smaller units at each recepticle). Run a bunch of lines to the gear, all home-run with no junction boxes.
Finally, when you run these lines make sure that they are all spaced apart and if they have to cross any other wires that it is at a 90 degree angle to avoid interference.
I'm sure others here have more suggestions...
Thanks Elevick - hoping to get some suggestions about the number of discreet lines I should run, and which equipment should each line feed. Also, any concerns/suggestions about hot wire phase. That is should the dedicated lines be the same phase?
Indeed run all you lines on the same phase otherwise you can easily get a ground loop. In my listening room I have 2 sets of 3 dedicated lines 3 on one leg 3 on the other, one group is for the SS system the other for the tubed system.

Good Listening

Peter
Any suggestions on the gauge, e.g., 12 gauge for 15-20 amps (??) 10 gauge for 30 amps. Would it be a good or bad idea to feed the tube amp and self powered D class sub woofer on the same 10 gauge - 30 amp line? I recall that some folks may have advised to keep the CDP (digital device) on its own line, 15 to 20 amp line should more than enough? Can I hook the TT into the same line with the CDP? This is the type of advice I'm looking for. Thanks
I ran 30 amp sub box from my main panel using six gauge wire.
10 gauge wire for all of my dedicated lines and used 20 amp circuit breakers.
Digital should be on a dedicated line all by itself.
Just a suggestion but amp by itself, preamp and TT could be on the same line.
One line for the self powered sub.
Would not hurt to throw in one extra dedicated line while you are doing all that work to have just incase you want it, or to experiment with.
dedicated line per each channel/component.
You won't get a ground loop by running lines on opposite circuits from the panel. The ground is the same. Most, if not all qualified electricians will calculate the load of the circuits and split them at the panel to keep the house loads approximately equal so as to not overload one side. Based on your equipment listing, I would recommend three separate indepent circuits. I have mentioned this many times. 1) for all of your low level electronics, DAC, CD Transport, music server, pre-amp, phono stage, TT, tuner plugged into the same power conditioner and into one circuit. 2) stereo amp into it's own circuit, if you want eventually two mono amps, then run another circuit for good measure. 3) separate circuit for all of your home theater equipment also plugged into a separate power condition or outlet box. So, if you may have two mono amps, then one circuit for each amp, one circuit for all the low level audio electronics and one circuit for all your home theater electronics, each to an independent circuit back to the panel. Split the loads equally at the panel. Do not! put all of the load on one side of the panel circuit. this is a basic violation or electrical rules and will not prevent ground loops. Ground loops are caused by something all together different. if you have a raised foundation, it is relatively easy to run new circuits. If you have an attic, it is also relatively easy. However, a good qualified electrician can do wonders. Also, it is really not expensive to run indendent circuits. Plan carefully where your equipment will be situated before installing the outlets.

enjoy
Most, if not all qualified electricians will calculate the load of the circuits and split them at the panel to keep the house loads approximately equal so as to not overload one side.
05-13-13: Minorl

I would bet all of Bifwynne audio equipment loads added together would not total more than 8 to 10 amps continuous load, if that. Most hair dryers pulls more current than that.

It is an established best practice that when audio equipment is connected together by ICs the AC power feeding the equipment should be fed from the same Line, leg, of the same electrical panel.

The worst thing that Bifwynne could do is have an electrician install a 120/240V multi wire branch circuit. (2 hot conductors with a common shared neutral conductor.) What better way to couple the power supply of digital equipment to the power supply of analog.

Bifwynne wants dedicated branch circuits installed, not separate circuits.

Split Single Phase electrical service is most commonly found in residences and smaller commercial buildings,
and is commonly used to feed AV equipment. One key advantage that single phase has over three phase
is that while harmonic currents are still present, it is not possible for the “triplen” components to add in the
neutral. In addition, use of split single phase can result in at least a 6dB reduction in noise floor as compared
to three phase if the capacitances of the connected equipment are relatively well balanced. However, 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.
http://www.exactpower.com/elite/assets/pdfs/theTRUTH.pdf
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I've been at this for quite some time and have experienced absolutely no problems splitting the load at the panel. First, I am a qualified electrician also and this is a basic element. Second, a dedicated line is just that. It can be run from either side of the panel, with the neutral and ground coming from the the neutral and ground points in the panel. Like I mentioned earlier, ground loops are not caused by this. They are caused by faulty design/contructed electronics with bad internal grounding systems, bad cables, etc. After I ran my dedicated lines, the noise floor dropped dramatically. No ground loops and absolute quiet. I also adhere to my philosophy of tying all low level electronics to the same power conditioner via a dedicated line and my two amps have their own dedicate line to the panel. and Yes! the amps are on different sides of the panel load. Dead quiet! and no ground loops and no cheater plugs. No way leakage can seep in the electronics. Each dedicated line has its own ground line and neutral back to the panel where they all terminate in a star like configuration. They all terminate at the same neutral and ground point at the panel. I can't explain it any better or clearer. But, it is not a point worth arguing. Each run of Romex has (three conductors in it. Hot, neutral and ground). So, each dedicated line has it's own three conductor Romex run from the panel to the outlet. This is how there is no leakage or sharing of neutral or ground. I think that is where the confusion arose. Some electricians will run lines and share neutrals. I don't.
I would rather err on the side of caution Bifwynne. Too many different people have posted in these forums to install dedicated lines on the same leg. I would not ignore that.
I've been at this for quite some time and have experienced absolutely no problems splitting the load at the panel. First, I am a qualified electrician also and this is a basic element. Second, a dedicated line is just that. It can be run from either side of the panel, with the neutral and ground coming from the the neutral and ground points in the panel.
05-14-13: Minorl

Yes a dedicated branch circuit can be fed from either Line, leg, in the panel.

I noticed you chose to use the word dedicated and not separate in your last post.

Like I said in my last post if a customer said he wanted two separate circuits he could end up with a multi wire 3 wire + ground branch circuit. Two hot conductors with a common shared neutral and equipment ground conductor.

Installation could be 14/3 with grd, 12/3 with grd, or 10/3 with grd. Two separate 120V circuits.
And of course according to NEC code each circuit shall be connected to opposite Lines, legs of the panel. NEC 2008 connected to a 2 pole common trip handle breaker.

Why do I press the difference between dedicated branch circuits and separate circuits? To educate the layman here that post questions about adding multiple circuits for their audio equipment. You tell an electrician you want a price for installing two 20 amp separate circuits what are the chances of him installing 12/3 with grd NM-B cable instead of two 12/2 with grd NM-B cables. Especially in a 2 gang cut in box.

As for feeding multiple dedicated branch circuits from the same Line, leg, in the panel, where equipment is connected together by ICs, I have stated the accepted norm.

Take the time to read the link I provided in my last post.
There are many others out there that pretty much say the same thing.

The leakage the article talks of, could be, capacitive leakage of the audio equipment power transformers.

However, 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.
If the average total connected audio equipment load is less than 10 amps why take the chance of added noise by feeding branch circuits off each of the 2 hot legs?

I suggest you read NEC Article 90.1 (A), (B), and (C).
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There is a difference between a dedicated line and clean power. A dedicated line will suffice in most home owners audio setup, but 'clean power' is something to consider if you have a large amount of dinero into your audio equipment.

Clean power vs dirty power...clean power will always be a line from the main panel to a transformer then to the sub panel with isolated grounds then to the equipment.
So Jea48, I'm also planning to get 2 dedicated lines, 1 for digital and one for analog. I'm not sure what to tell the electrician and I don't understand branch circuits. I plan to request 10 or 12 awg romex.
I totally agree with MinorL every electrician I've worked with and talked to all say the same thing. This topic has been going on for years where other electricians have said more or less the same thing. I recall one electrician was so frustrated that in his last post he explained again the proper way to install a dedicated panel in a breaker panel, but no sooner his post was posted, these people with probably no qualifications post the same misguided information. You can check my post under "Dedicated power line for audio equipment". With this setup you will have a solid foundation to start with. The most important part of the installation is the wiring techniques I've developed.
I will share this for now, use 10 gauge stranded THHN wire, red insulation for the hot, white insulation for the neutral (return) and green insulation for the ground, no romex please.

MinorL if you are interested I'll be more than happy to discuss this topic with you.

Btselect
Jea..., I tried cutting through the NEC material. Have to admit, I got lost. As I said, I will hire a licensed electrician to install separate lines from the circuit box, or a "satellite" box off the mains to run discrete and separate lines. If I got anything off the web site, I should run single phase Romex (1 hot, 1 neutral and 1 ground). What I'm still confused about is whether I should run hot wires from both sides of the box. My concern is whether powering my gear with different phase hots could in some way change the output phase of my gear.
Foster_9,

I can only give you general advice. The electrician you hire will know what he must do to meet the minimum electrical code standards in your area.

Note I said minimum. You can go overboard as much as you can afford.

12 gauge or 10 gauge? Short runs 12 is probably more than adequate. But if you go with 10 gauge you will never wonder what if.....

Tell the electrician you want two 20 amp 120V dedicated branch circuits installed.

NM-B, (Romex is a trade name), if possible.

The electrician should be able to keep the two cable runs fairly close in length with one another. Some separation between the two cables for long parallel distances if possible.

Plastic cut in boxes if possible. Two separate boxes. Not a 2 gang box. Just in case of a wall wart power supply, physical size.

I assume your home is wood studs with drywall.

Tell him you want both hot conductors of the branch circuits connected to 20 amp branch circuit breakers fed from the same Line, leg, in the panel.
To verify after the installation is completed and power is turned on have the electrician show you both circuits are fed from the same Line, leg, by measuring for voltage from the hot contacts from one duplex receptacle to the other duplex receptacles.
Same Line, leg, zero volts. Off each Line, leg, 240V.

If possible the breakers should be located away from known noisy load breakers. Example, Furnace, laundry, sump pump, Microwave, ect.

Forget about asking the electrician to move all noisy loads to one Line and put your new dedicated circuits on the other. If he is a licensed electrician worth his salt he will tell you no he cannot do that. Nor would you want him to.

If the main disconnect breaker is installed in the panel the new branch circuits will be fed from ask him if he can keep the neutral and equipment grounds grouped close together on the same neutral/ground bar.
.
Bifwynne,

I tried cutting through the NEC material. Have to admit, I got lost.
Bifwynne
LOL.

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.

B) Adequacy. This Code contains provisions considered necessary for safety. Compliance therewith and proper maintenance results 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.

FPN: Hazards often occur because of overloading of wiring systems by methods or usage not in conformity with this Code. This occurs because initial wiring did not provide for increases in the use of electricity. An initial adequate installation and reasonable provisions for system changes provide for increase in the use of electricity.

(C) Intention. This Code is not intended as a design specification or instruction manual for untrained persons.

(D) Relation to Other International Standards. The requirements in this Code address the fundamental principles of protection for safety contained in Section 131 of International Electrotechnical Commission Standard 60364-1, Electrical Installation of Buildings.

FPN: IEC 60364-, Section 131, contains fundamental principles of protection for safety that encompass protection against electric shock, protection against thermal effects, protection against overcurrent, protection against fault currents, and protection against overvoltage. All of these potential hazards are addressed by the requirements in this Code.

Look Closely at Section (B) Adequacy it reads as follows: "Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electric use."
http://www.spgs-ground.com/information/-purpose-of-the-national-electrical-code

FPN:?
Are suggestions only.

Code is bare minimum electrical safety standards. NEC is not meant to be used as an instruction manual.

.
.
What I'm still confused about is whether I should run hot wires from both sides of the box. My concern is whether powering my gear with different phase hots could in some way change the output phase of my gear.
Bifwynne
Either way it will not change the polarity or phase of the output of your gear.

I looked at your equipment. Everything added up, the total connected load can't be more than 10 or 12 amps continuous max. And that would be if you pushed the amp near full power.

Have the electrician feed the dedicated branch circuits from the same line, leg, of the panel.
You do not want a 240V potential, voltage, between the hots of your dedicated branch circuit receptacles where audio equipment will be be connected together by ICs. You want zero potential from hot to hot. And you will have zero if the branch circuits are fed from the same Line, leg of the electrical panel.
.
Got it! My thought is that the in-wall house circuits will feed the TV, the DVD player and the VPI TT. Four (4) separate dedicated lines for: (1) the amp; (2) the analogue fronts (linestage and phono pre); (3) the CDP; and (4) the sub-woofer. Will set up a satellite box off the main panel for the 4 lines -- will use only hot from one side of the main panel and will ask the electrician to link the sub-panel as far away from other breakers that feed motors and the HVAC system. Does this sound like a good plan?
This is really interesting reading all the posts and suggestions. 1) show me evidence where connecting electronics on the panel as balanced loads split evenly between phases actually causes ground loops and noise. I would bet money that this is an assumption made by people that have no idea what was actually causing their noise and ground loops. 2) Every qualified electrician will ask an important question before installing the new panel box and wiring the "dedicated" lines. That question will be "what will the specific loads be on each phase? And a qualified electrician that is concerned with not violating basic safety and code will pull out a calculator and split the loads equally. I'm not going to argue with anyone here regarding this issue. it is what it is. When I wrote separate lines, I actually meant "dedicated Lines" specifically lines that have three conductors per line. A hot wire, neutral and ground that are not shared with any other circuit and are dedicated lines all the way back to the panel. That is what I meant. I don't care if you use separate conductors or three conductor "Romex" type conductors. It is up to you and your electrician as long as it meets or exceeds code and serves your purpose. Sharing neutrals will absolutely contribute to ground loops and noise. And yes, you have to be very clear to the electrician in the instructions. Tell the electrician that you want "dedicate" lines with a hot, neutral and ground per dedicated line and to not share ground and neutrals. If your system doesn't draw massive current per phase, then it really won't make a difference if you connect it on one phase. However, if you have stupidly massive equipment that is on all the time and draws continuous current, this may overload one phase and is a basic violation of electrical code. Period! I read posts all the time where some well meaning person suggest to someone to do something to "fix" a problem and that "fix" is a violation of some code or safety standard. Such as the continuous use of "cheater Plug" or some other non-sense. But, they wont' be around when someone gets hurt will they? also, if you wire your panel incorrectly and a fire occurs and your insurance company finds out that it was purposely wired incorrectly, this may void your insurance coverage. I'm just saying... Do it correct the first time.
My recommendation comes from years of testing different electrical setups, wiring techniques, components etc., everything you have read here on audiogon I've tried and countless more. The key question here is what actually works, have you actually done these types of testing in the proper manner. An example, breakers and receptacles the main difference between them that makes the biggest difference in sound is the mechanism that secures the wire, then choosing the type of material, plating, etc. they are made of. The good receptacles always give you the option of material but they never offer different mechanisms for securing the wire. Look at a GE breaker, the wire is squeezed tight along the whole circumference of the wire giving maximum surface contact and no air gap, a solid design (one of many reasons I use stranded wire). The main difference between a commercial panel and a homeowner one are the larger copper bars the breakers are secured on, and how they are secured bolted versus pressure fitted. I don't use plastic receptacle boxes simply because after countless times of pulling the power chord out of the receptacle the screws that secure the receptacle to the plastic box simply give out. There are just too many things to go over and do, both large and small that affect the quality of your electrical set-up. There is no electrician that will do what is required simply because they were never taught this. I've worked with a lot of electricians to know that no 2 are alike, I've worked with one electrician for over 10 years now, so he knows what needs to be done. One last thing to consider, what if the people giving the recommendations are wrong, with my set-up you don't have to rip out the walls to make changes.
Minorl, I take your point. The biggest energy vampires in my system are the power amp and the sub woofer. The rest of the gear doesn't draw that much current. Let me be clear. If the line stage and phono pre are fed off a true dedicated line from the box off one hot and the amp and sub are fed off true dedicated lines from the box with the other hot of opposite phase, will that set up result in the line stage/phono pre outputs being out of phase with the power amp and sub?
Every qualified electrician will ask an important question before installing the new panel box and wiring the "dedicated" lines. That question will be "what will the specific loads be on each phase? And a qualified electrician that is concerned with not violating basic safety and code will pull out a calculator and split the loads equally.
05-15-13: Minorl

And for a non audiophile electrician the conversation will go something like this.

Electrician.
"So you want 4 - 20 amp dedicated circuits.
You want me to install #10 gauge Romex wire.
My goodness how much power does your audio equipment draw?
#12 is good for 20 amps per code. Who told you, you needed #10?
So how much power does your audio equipment need?"

Customer.
"Well, my tube CDP I think is around 50 watts. My tube preamp is around 150 watts. My tube phono preamp is around 30 watts. My Power amp is rated at 120 WPC. At full power output of 120 watts it could draw around 700 to 800 watts (800W 6.7 amps full power). My sub I am not sure but class D draws less power than an A/B sub amp."

"I have a large screen plasma TV and a DVD player. I think that stuff can run off the house circuits." (Bifwynne quote)

Electrician.
" So what are you feeding all this stuff off of now?

Customer.
"Just the existing wall outlet."

Electrician.
"You know that is more than likely a 15 amp circuit, fed from a 15 amp breaker."

Customer.
"Funny story -- one day my kid was playing Rosetta. I think it's a band that plays music, or at least that what my kid says. Tons of bass. When the band kicked into "low gear," first the basement lights dimmed, then the circuit breaker tripped." (Bifwynne quote)

Electrician.
"Sounds like the lights are on the same circuit as well."

Electrician.
"Just curious, why do you think you need 4 new 20 amp circuits? I mean I will do what ever you want.... I will say one thing for sure, You will just be wasting your money having me install #10 Romex wire."

Customer.
"Are you sure?"

Electrician.
"OH Ya." #12 is plenty big enough. By code I only need to use #12 wire for a 20 amp circuit. And you really don't have any load to speak of. I mean you are running everything plus the lights off of one circuit now."

Customer.
"Oh I forgot to mention, Can you put the new circuits on the same phase in the electrical panel."

Electrician.
"I will have to check if you have enough empty spaces left in your electrician panel."

Customer
"Somebody told me that an electrician would tell me he couldn't do that." Something about balancing the load across the two hot phases."

Electrician.
"Well technically that is usually the case. But in your case you don't have any load to speak of. You are feeding it all off a 15 amp breaker now."

"I will check your Mains and see if the hot "phases" are somewhat balanced now. The only sure way, to be honest with you, would be for me to put a recording meter on them for a couple of days. Loads are changing constantly."
>>>>>>>>>>>



My rig consists of the following gear: (1) self powered sub that is rated at 1500 "Class D" watts; 4500 watts on a surge; (2) ARC tube CDP; (3) ARC tube line stage; (4) ARC tube power amp rated at 120 wpc - supposedly draws 700-800 watts when driven hard; (5) ARC tube phono pre; and VPI TT. I have a large screen plasma TV and a DVD player. I think that stuff can run off the house circuits.

Right now, everything I just listed is sucking juice off the same line. I gotta believe no good is coming from that set-up. Funny story -- one day my kid was playing Rosetta. I think it's a band that plays music, or at least that what my kid says. Tons of bass. When the band kicked into "low gear," first the basement lights dimmed, then the circuit breaker tripped.
Bifwynne
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05-14-13: Bifwynne
My concern is whether powering my gear with different phase hots could in some way change the output phase of my gear.
As Jim (Jea48) indicated, the answer is no. AC phase has nothing to do with audio signal phase. As you will realize, the audio signal path is powered by DC, which is created from the AC by the power supply of each component.

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
Jea48 -- great post. Kudos on your prescience!!!

Al -- on the one hand you say balancing the load between the two phases has no relevance to the output phases of my gear because the AC current is converted to DC anyway. Ok, that makes sense. OTOH, you quote from the handbook that says running dedicated lines that use different phase hots increases the chance for ground loop related hum and noise. Bottom line: is the smart move to use same phase dedicated lines, BUT ask the electrician to move other house circuits to the other hot phase rail to keep the house load balanced??

Thanks, Bruce
Is the smart move to use same phase dedicated lines, BUT ask the electrician to move other house circuits to the other hot phase rail to keep the house load balanced??
Hi Bruce,

Most likely redistributing other loads is not worth worrying about. See the last two paragraphs of Jim's post just above.

Best regards,
-- Al
Al,

Thank you for your kind words.
Jim
Bifwynne; In response to your question, the answer is no, the signals will not be out of phase if connected to different phases of the electrical panel. I suggest to the OP to be very clear in the instructions to the electrician. If you want 10 gauge conductor and are willing to pay for it, then so instruct the electrician. If you want 20 amp service per dedicated line, then also so instruct the electrician. Same for separate conductors as opposed to "Romex" style conductors. You can't go wrong with 10 gauge, 20 amp service per dedicated line. Each dedicated line having its own ground, hot and neutral back to the panel and will not be shared. If you want to place all your electronics on one phase at the panel. Go for it. If the load is too high and unbalanced, a good electrician will not do it. However, some will. Also, you will not have ground loops or noise if you split the load to each phase on the panel. Not if the ground and neutral are dedicated and not shared. They all terminate (and I mean all of them) back at the same ground and neutral point in the panel anyway. But, go for it anyway you want. just don't violate code and risk issues as I mentioned previously. Be on the safe side, and follow proper electrial standards. Again 99% of ground loops are caused by improperly designed and constructed equipment with bad internal grounding schemes and poor interconnect cables. You will appreciate dedicated lines.
Minorl,

What is your take on the reason why you should put all your audio equipment on one leg and putting all your noisy devices on the other to avoid noise transfer. My understanding is a electrical device sucks electricity in and it's a one way street, the device then generates noise, etc., which then goes back into the system via the neutral or return line. The return line for both legs are then tied together along with the ground, making the ground a very important point to eliminate noise, and not the hot line as the key culprit.
A few thoughts.
1.The home insurance issue is major. Be legal or very possibly be out of luck even if the fire fault was not the wiring you installed!
2.Go big guage (10)and just as important- quality well shielded wire. Best bet would to scavenge some excess wire used for robotic controls. It has stringent and valuable characteristics far surpassing the generics you speak of- and the design quality is for robust, failsafe accurate signal transmission-quite desirable for high quality power supply, regardless of the power level.
3.Remember that an average load of even 6 or 7 amps will probably result in instantaneous draws of up to 150 amps. Bigger guage is beneficial.
4. noise from equipment can reflect on all 3 lines.
5. I'm assuming what you want is adaquate clean power to your equipment.With the price of copper and labor today I highly suggest a consultation with an electrician regarding load distribution and economical ways of making what you have accomodate your requirements for power.
6. to clean your power consider installing 1, 2 or 3 of the Equitech (I have zero affiliation or interest)"blemished", cheap balanced transformers. Fabulous improvement-way ahead of dedicated line. Dedicated lines are still garbage laden from the outside power utility and noise from your home. Finely balanced power works miracles. (if its good enough for super delicate medical and research work , NASA, etc, it will benefit you.
(I have a so called state of the art preamp with a lauded separate ps. Adding the balanced transformer was like--magic. It clearly revealed the power supply to be the weakest link(very weak) in my otherwise terrific pre.
7. under no circumstances have digital,television,etc connected to same power source as your sensitive analog electronics. I've been fussy about power and conditioning for years and it has paid off; however, it wasn't until I established a separate isolation transformer for my digital source , on top of all dedicated lines and balanced transformer isolation for my pre and amp, that I really got the full benefit of years of working on my system.
It is magic for digital; all the big boys are well aware of it.
Best wishes. Pete
There are many ways that noise can be added to the power lines. Large industrial motors, generators on the system, etc. However, when in your home, it can come from florescent lighting, refrigerator motors, microwaves, etc. You can actually scope the power line and see noise on it. A very good piece of equipment will have inherent internal power supply filtering that will remove the vast majority of this noise when converting to DC. Some have large coils in the power supply circuitry also that help with this. Your friendly neighborhood power company will acutally test your home system (if you complain and ask) and see if noise is present, or low voltage, or flickering (yes voltage flickering). Here is how you fix this. 1) remove all bad lighting,2) get a decent power conditioner for your low level electrics to plug into as I mentioned previously. I wouldn't swap around circuitry in the home. This is really a non-issue to me. If one is careful, run dedicated lines (with separate and unshared neutrals and ground conductors), proper interconnect cabling helps. I'm the first house off the power transformer for my area, so I have great voltage. Four dedicated lines for my system (which includes separate ground and neutrals for each dedicated line), CD, TT, Tuner, Pre-amp, Phono stage, DAC, electronic crossover all plugged into a very nice power conditioner and that is plugged into a dedicated circuit. Two stereo amps each plugged into its own dedicated circuit. Result, dead quiet.No ground loop, no refrigerator noise, no microwave noise, no lighting noise, no flickering, no voltage sagging, just music. However, I do believe it is important to not share neutrals or grounds on lines for the music system.
Jea48. Your comments were great. I had emphasized to call an electrician, and emphasized going by the code. You have really clarified the proper approach to the entire setup. I thank you for all the readers who benefited from your detailed, and for the most part, unknown knowledge.
I came across this thread and thought I would post something a little different than what other people are doing. I decided to isolate my digital from my analog.

I have 3 30 amp 220 volt circuits feeding my stereo with 10 gage wire in my new dedicated room. The circuits are feeding 3 power isolators two 3 kilowatt isolators and one 5 kilowatt isolator. The isolators are transformer based units. The 5 kilowatt isolator has two 110 volt feeds, one for analog and one for digital. The 3 kilowatt isolators each feed 1 mono block amp. I am using hospital grade copper plugs to feed all my gear.

This seems to work well for my system. The isolators are located under my house on a concrete slab off so I don’t hear the hum. I like using 220 volt better so you don’t have to run a neutral line to the isolator. Seems like to me the neutral line is where a lot of the noise comes from.
Coxhaus,

Just curious have you ever checked if the outputs of your three isolation transformers are in phase with one another?

Simple test.
Using a volt meter/multi meter set the meter to AC auto or for AC over 300Vac.

Insert one test lead probe in the hot contact, small slot, of a receptacle fed from one transformer and the other test lead probe into the hot, small slot, of a receptacle fed from one of the other transformers.

If in phase you will measure 0 Vac nominal. If out of phase you will measure 240Vac nominal. Check each hot to hot contact from each receptacle fed from each transformer.

If out of phase the 240Vac nominal is lethal real potential power, not phantom power.

You want the outputs of the isolation transformers to be in phase with one another where audio equipment is connected together by ICs.
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How is this different than people who plug into multiple plugs which are in different phases of their breaker box? Most people do not know what phase every plug is in their house nor do they go to the trouble to figure it out.

The sound is great from the isolators.
Jea. Why not test them independently?
Jea. Why not test them independently?
06-17-13: Ptss
Ptss,

Test what independently?
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Jea48. The outputs of the 3 transformers; as you suggested June 14.
Ptss,

I assume that was done before the three new separately derived grounded AC power systems were put into service.

*Check unloaded voltage.
*Check Hot to ground to verify the neutral is grounded.
*Check for AC polarity at load receptacles.
*Connect load/s and check voltage again.

The test I suggested, in my post of 06-14-13, is to find if the three xfmrs outputs are in phase or out of phase with one another.

The same test used to make sure multiple dedicated branch circuits are fed from the same Line, leg, from the electrical panel.
An accepted norm where audio equipment is connected together by ICs.
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Split Single Phase electrical service is most commonly found in residences and smaller commercial buildings,
and is commonly used to feed AV equipment. One key advantage that single phase has over three phase
is that while harmonic currents are still present, it is not possible for the “triplen” components to add in the
neutral. In addition, use of split single phase can result in at least a 6dB reduction in noise floor as compared
to three phase if the capacitances of the connected equipment are relatively well balanced. However, 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.
http://www.exactpower.com/elite/assets/pdfs/theTRUTH.pdf
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Jim
Jea. Can't imagine what you are on about bringing 3 phase power into this. Hmm. I believe most people are going to install their 'power systems?' correctly, regardless of the type of conditioning they will use. Just an assumption.

I think if I understand it, if you use both phases of power at home then if you cross the hots you can produce 240volts. I would think anybody who uses 220 power conditioning is subject to this and anybody who uses multiple plugs from different phases are all in the same boat.
You are advocating only using one phase for stereo use.
I have a 55 year old house with an original 100 amp service which, in a way, worked in my favor because I was forced to upgrade. I did this approx 15 years ago with the addition of a 200 amp box bypassing the old one to serve 220V users such as the clothes dryer, stove and A/C air handler. The 100W box was otherwise left unchanged feeding all other existing circuits in the house. This was a matter of convenience because the 100 amp box is in the garage.

Modifications that were made to serve the sound system were done primarily to protect it, to the extent possible, from potential damage from power feed glitches. I didn't consider it from the standpoint of maximizing sonic quality and it still wouldn't be a priority in my thinking today. Anyway, the modification consisted of a lightning arrestor with surge protection and separate 30 amp breakers from the 200 amp panel serving two outlets on the wall which serves the system. I also use a line conditioner for most of the components in the system. I'm sure that there are some purists that would cringe at all these intervening electronics and several have already reminded me that this protection may provide some peace of mind but is mostly not that effective.

From a purely sonics standpoint, and I'm still not convinced that this is an important issue, I may have gained something by accident. The electrician did use 10 gauge Romex from a roll on his truck and the run of these two wires was relatively short (approx 25ft). They were run in the garage attic, parallel to one another with no crossing of other conductors, and the installation in question was far removed from "noisy" installations such as the central air handler by about 60'.

I don't think I added much to the conversation except to remind those who are doing upgrades to their house power, that it's a good idea and pretty simple, to make accommodations for your sound system at the same time.
I also live in an old house and upgraded my service. I had my service upgraded to a 250 amp service with new breaker box and what I think helped the most is changing to new 0/0 wire from the pole to the new breaker box. The new feed to the house is a much larger wire.
I think if I understand it, if you use both phases of power at home then if you cross the hots you can produce 240volts.
06-21-13:

Coxhaus,

A little background.

Most homes in housing developments in the US are fed from a single phase transformer. The 240V nominal secondary winding has a center tap, CT, midpoint of the winding. The CT is called the neutral.
The secondary winding is called a split phase winding.

The neutral is intentionally connected to earth at the main electrical service of the house. The neutral then becomes the Grounded Conductor.
The other two conductors are called the Ungrounded Conductors. Also referred to as the Hot conductors.

From Hot to Hot conductor there is a difference of potential, voltage, of 240V nominal. From either Hot conductor to the neutral conductor there will be 120V, nominal.
Thus a 120/240Vac grounded 3 wire single phase power system.

Click on single phase power systems.
http://openbookproject.net/electricCircuits/AC/AC_10.html#xtocid174140

I would think anybody who uses 220 power conditioning is subject to this and anybody who uses multiple plugs from different phases are all in the same boat.
If you would take the time and research the archives of audio forums you will find the vast majority of audiophiles when feeding their audio equipment from two or more 120V branch circuits will feed the circuits from branch circuit breakers that are fed from the same Line in the electrical panel, when the equipment is connected together by ICs. All from Line one (L1) or all from Line two (L2) but not from both.

As for your 3 isolation transformers you have the same situation. It doesn't matter whether you fed the xfmrs with 240V or 120V. (240V is best IMO). Two of the 3 will be in phase with one another. The other has a 50/50 chance of being in phase with the other two. My simple test, in one of my previous posts above, will tell you for sure.

IF one of the xfmrs is out of phase with the other two all that needs to be done is to reverse the two primary hot branch circuit wires at the breaker that feeds that xfmr.

Transformer phasing?

Click on phasing.
http://openbookproject.net/electricCircuits/AC/AC_9.html#xtocid174063
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This is a good thread. I got help here a number of years ago when I had dedicated lines installed in my current room. A couple of anecdotal observations, while I am not an electrician and don't pretend such expertise:
1. I thought choosing one leg over another was about finding the side which had less noisy appliances, lighting, etc. connected to it.
2. I agree that we tend to over spec, given the amount of actual current drawn by our gear- thus, having separate dedicated lines to support amps, separate from front end electronics, etc. But, in my experience, using very high efficiency horns, I could hear low level grounding issues that I attributed to the 'difference' in separate lines, i.e., the 'Brits' tend to hook everything up to a single line and then use a distribution box in the room.
3. I like the idea of separating lines for analog and digital but if they are ultimately hooked up to either other through interconnects, i.e, a HT system that connects to the audio system, how much difference does that make? (My HT is entirely separate from the hi-fi and uses a 240 volt step down transformer to isolate it from an analog only hi-fi system).
1. I thought choosing one leg over another was about finding the side which had less noisy appliances, lighting, etc. connected to it.
06-24-13: Whart
There are those that follow that belief. Keep in mind when the house was originally wired 120V branch circuits for the kitchen, laundry, furnace, lighting loads, and whatever other possible loads were somewhat evenly divided, balanced, across L1 and L2 to neutral at the service panel.

In most cases our homes are fed from a utility power transformer with a split phase secondary winding. The way a split phase winding works only the 120V unbalanced load returns on the neutral conductor to the source, the utility transformer.

Example. Say L1 to neutral has total connected load of 20 amps for a given point in time. L2 to neutral has a total connected load of 10 amps at the same given point in time. Only 10 amps will return on the service neutral conductor to the source.
The remaining balanced 10 amps is in series across L1 and L2.

Example. Say both 120V L1 to neutral and L2 to neutral loads are exactly 20 amps each.... 0 amps will return on the service neutral conductor to the source, xfmr.
The two 20 amp 120V loads are in series with one another and are being fed by 240V.

Single phase power systems.

So, so much for trying to feed your audio equipment from one Line or the other because of noisy appliances/equipment.

I do believe it helps not to have dedicated branch circuit breakers that will feed audio equipment installed right next to breakers that feed noisy electrical appliances/equipment. Whether the noisy loads are 120V or 240V. A 240V load example would be the air conditioner condensing unit outside of the home.
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Jea48,
I finally did the test on the hots of my isolated power. Maybe I was lucky or the transformers just handle it but when I tested the 120V loads together 2 at a time they all read 0 volts.
lee