Dedicated Power Lines

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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Al,

Thank you for your kind words.
Jim

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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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.
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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.

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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.
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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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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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Jea. Why not test them independently?
06-17-13: Ptss

Ptss,

Test what independently?
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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
.
Jim

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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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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