Dedicated Outlets - The Latest Recommendations


This topic has received a lot of attention over the years, but I'm having trouble pulling all the pieces together so that I can communicate to the electrician exactly what it is I'd like to have done.

I'm hoping to add two separate, 20 amp lines for my audio equipment, and since we are having our roof redone, this presents an ideal window for a project like this.

The service panel is on the lower level of the house near an outside wall, and the lines would come up the wall, travel across the space above the ceiling and under the roof (roughly 12 inches), and then down an inner wall to a room on the upper level.

I'd like to know what type of wire is best to use (the total distance from panel to outlets is about 75 feet), how it should be attached to the service panel, and what type of outlets are recommended.

I recall seeing advice in the forums to use twisted wire to reduce hum and EMI, and not to have the two runs too close to each other.

Any advice for specifying specific materials, and communicating with a non-audiophile electrician would be greatly appreciated!

And I'm hoping Jea48 and other knowledgeable members will chime in with either sage advice, or links to relevant sections of past discussions.  Perhaps we can make this thread a starting point for others contemplating similar projects.
rel
While awaiting @Jea48’s response (and I agree that he is always superb on these issues), here’s what I did, within code in Austin. recently.
Subpanel off main panel- mainly to give me more room for breakers. I installed a big outdoor isolation transformer, but you don’t have to do that. The output of the transformer was run through 4 gauge feeder wires to another subpanel near the room upstairs. (Without the transformer in the middle, you will probably still want a subpanel with a copper buss bar near the room which I believe is why the heavy gauge wire was used as a feeder). I didn’t use "audiophile" wire from the system subpanel to the outlets- just 10 gauge Romex. I learned from past experience that these have to be spaced apart, because if they are bundled, current or electrical noise on one of these runs can affect the others.
You have to figure out where you want the outlets for the dedicated lines. I didn’t use fancy $400 receptacles, but Albert Porter’s medical grade Hubbell 20 amp receptacles.
I had my electrical contractor pull a permit- they took care of all of that.
I’m sure there are other questions-- issues like which side or phase of the 120 volt legs from a 240 volt system- balancing it for load is normal- the theory is you want the system on the side that doesn’t have the noisy appliances. (This is less of an issue with the isolation transformer).
Grounding- all must come back to the main household ground. JEA can speak to the value or downside of additional grounding rods. You can’t really run a ground that is not in some way connected back (bonded may be the term of art) to the main household ground and electrical service. It is worth having the electrician check your current grounding set up, and how the current service panel is wired, just to make sure what’s already there is in order, so it doesn’t impair what you add. Dedicated lines are not really fully isolated from the main household electrical system, but help- you aren’t suffering current draw or noise from other appliances, lighting, etc. on the same branch. However, in my last system, there were certain low voltage fixtures elsewhere in the house, and certain appliances, that could generate a low level hum or noise despite the dedicated lines. Simple solution- don’t turn those on when you are listening.
I’m sure others, including Jea, can add more, or clarify or correct anything I’ve said. I’m not an electrician, but that’s a short version of what I know. Good luck.
What about feeding the sytem in totally independent fashion off a generator ? Sorry, if I asked nonsense.
I'm going to leave the wiring suggestions to the professionals, jea48, almarg, and others.

As far as AC outlets are concerned, that's a very subjective area and there are many good products available depending on how much money you want to spend.

I totally agree that for the money Albert Porter’s outlets sold on Audiogon are very good and priced very reasonably. Due to the makeup of them and the cryogenic treatment I find that they sound better than store bought off the shelf AC outlets (that's another area of disagreement). I still own several of Alberts outlets.

After trying a dozen of different audiophile grade outlets I finally settled on my current outlets which is the Furutech GTX-D Rhodium (R) outlet. I own five of them and  am very appy with there sound.
+1 Furutech GTD-D Rhodium outlets.

I am using these in my dedicated theater room and very pleased with the sound. Yes, they are expensive but well worth the price. Also they don’t damage the coating on your male AC plugs.

If you going by the code, 12 gauge Romex wire is designated for 20-amp circuits.

I would also recommend surge protection installed in your main breaker box, like Environmental Potentials EP-2050 Surge and AC Waveform Correction and EP-2070 ground filters.

You may speak to Chris at VH Audio about these, he is a great resource and very helpful fellow.

Good luck!

If you going by the code, 12 gauge Romex wire is designated for 20-amp circuits.
Code is bare minimum electrical safety standards. The NEC should never be used as an instruction or design manual.
The service panel is on the lower level of the house near an outside wall, and the lines would come up the wall, travel across the space above the ceiling and under the roof (roughly 12 inches), and then down an inner wall to a room on the upper level.

I’d like to know what type of wire is best to use (the total distance from panel to outlets is about 75 feet), how it should be attached to the service panel, and what type of outlets are recommended.

The type of branch circuit wiring used and the wiring installation method used depends on local and or State electrical code. It also depends on the options the electrician has for the wiring installation method/s he can use for installing the branch circuit wiring. The electrician must meet bare minimum electrical code standards. That does not prohibit him from exceeding bare minimum electrical code standards. It’s what ever you can afford.

If you can use NM-B cable (Romex is a trade name) that seems to be the most popular. If you use NM-B cable have the electrician use plastic outlet boxes instead of steel boxes if possible.
Have the electrician keep the NM-B cables separated from one another when parallel to one another for long distances. Also try to keep them from other parallel branch circuits after he gets out the the electrical as soon as possible, within reason. Especially lighting branch circuits. (Dimmers, electronic ballasts, CFL lamps, LED lamps. All radiate RFI harmonics through the air.)
Example: https://www.youtube.com/watch?v=OCK5W9vlAE0

Two wire with ground solid core wire MC aluminum armor cable is also a good choice.
Example: https://www.lowes.com/pd/250-ft-10-2-Solid-Aluminum-MC-Cable/3637694

Because of the 75ft length of the branch circuits I would use #10awg solid core copper wire. Don’t let the electrician talk you out of it. Don’t let him try to talk you out of using solid core wire either. He will tell there is no difference between solid and stranded wire. LOL, for him there is, Stranded is easier to work with. Expect to pay a slightly higher labor cost though.

Install all dedicated branch circuits on the same Line, leg, breakers in the electrical panel. All on line 1 (L1) or all on (L2) (For audio equipment connected together by wire ICs.) (If big power hungry mono amps are used on their own dedicated branch circuits they may have to be fed from both L1 to neutral and L2 to neutral. Just never use any ground cheaters on the amps.)

If conduit must be used do not install more than one dedicated branch circuit in a conduit. (A true dedicated circuit does not share, occupy, the same conduit or cable assembly with any other branch circuit/s. (If installed in the same conduit, induced voltage from one to the other. With induced voltage possible AC noise.)

If conduit is used ask the electrician if he will twist the hot and neutral conductors together the entire length of the conduit run and pull the an insulated equipment grounding conductor in the conduit along side the hot and neutral twisted pair. If he can not or will not, then there is a very good chance, high probability, with a 75ft run of conduit with the hot and neutral wires pulled loosely in the conduit with the equipment grounding conductor wire you will have ground loop problems, 60Hz hum.

Use #10awg solid core copper wire. Yes the electrician can buy it at a wholesale house. I would not use #10awg stranded wire.... Stranded wire can smear the sound. (Labor cost for pre twisting and then installing the wire in the conduit will take some time. He may say you will have to pay him by the hour his hourly rate. Pre twisting the Hot and neutral wire together will be time consuming. Lightly to moderate twisting together of the hot and neutral wires only.)

If aluminum MC cable will work and meet electrical code I would use the MC over conduit. Electrical code in your area may require steel armor MC cable. Again your electrician will know what is code for your area.

Read pages 16 through 35. Mainly 31 through 35.
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

Jim
Many thanks to all for the suggestions, and apologies for my slow response.

Since @inna was first to respond, I went out and bought a generator, and hooked it up in my listening room.  Unfortunately, due to the racket, the only thing I could listen to was Lou Reed's "Metal Machine Music," which sounded pretty good--until I was overcome by the carbon monoxide.  Luckily, the generator eventually ran out of gas, and I slowly came around.  I'm thinking now that maybe I was supposed to leave the generator outside??

On the other hand, I really appreciate all the other suggestions, especially the highly specific ones from @jea48 .  I will attempt to digest all the specifics and communicate them to my electrician.  I have a feeling there may be a certain amount of arm twisting involved, but I'll see what he has to say.  Luckily, as a long-time audiophile, I'm used to people thinking I might be a bit whacky.

Thanks again!
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If you look for an electrical contractor that does commercial work, not just residential, you may already be in the ballpark in terms of dealing with some of this stuff (less arm-twisting). At least that's been my experience. Good luck.
I went through the same gyrations recently.  Here are a couple things to consider:

Use a panel that has a copper bus bar.  The only commercially available panel I found that fits the bill is a Square-D QO series panel.  The QO panels are more for commercial use...the copper is "tinned" so it will not look like copper though.  All other panels I looked at had aluminum bus bars, including the Square-D Homeline series.

Your electrician will really fight you when you tell him to put all circuits one one leg but stay strong!  FYI, in many panels each leg alternates from slot to slot on each side.....each side is not necessarily on one leg or the other.

One thing I did not do, that I suppose I could have, was to run 10-3 Romex instead of 10-2.  10-2 has two insulated legs and an uninsulated ground.  10-3 has three insulated legs and an uninsulated ground.  Some people recommend 10-3 and using the 3rd insulated wire as a ground and not using the uninsulated leg.  Supposedly it is possible for the uninsulated ground wire to act as an antennae for RFI.  Just something to chew on.  One caveat....10-3 is very very stiff.

Lastly, one thing I'd like clarified from someone else....How do you define a sub-panel?  We ran a dedicated panel for my audio circuits directly off the meter loop and gave it its own ground.  When I hear "sub-panel" I assume this means it is tapped off the main panel.

Good luck!
Corrections / Clarification:


If you can use NM-B cable (Romex is a trade name) that seems to be the most popular. If you use NM-B cable have the electrician use plastic outlet boxes instead of steel boxes if possible.
Have the electrician keep the NM-B cables separated from one another when parallel to one another for long distances. Also try to keep them from other parallel branch circuits after he gets out the the electrical as soon as possible, within reason. Especially lighting branch circuits. (Dimmers, electronic ballasts, CFL lamps, LED lamps. All radiate RFI harmonics through the air.)
Should read:
Also try to keep them from other parallel branch circuits after he gets out *of* the electrical *panel* as soon as possible, within reason.

.

Because of the 75ft length of the branch circuits I would use #10awg solid core copper wire. Don’t let the electrician talk you out of it. Don’t let him try to talk you out of using solid core wire either. He will tell there is no difference between solid and stranded wire. LOL, for him there is, Stranded is easier to work with. Expect to pay a slightly higher labor cost though.
Should read:
He will tell *you* there is no difference between solid and stranded wire.
.

If conduit is used ask the electrician if he will twist the hot and neutral conductors together the entire length of the conduit run and pull the insulated equipment grounding conductor in the conduit along side the hot and neutral twisted pair. If he can not or will not, then there is a very good chance, high probability, with a 75ft run of conduit with the hot and neutral wires pulled loosely in the conduit with the equipment grounding conductor wire you will have ground loop problems, 60Hz hum.

I should have added, though I have read the benefits of twisting the hot and neutral conductors together prior to installing them in an empty conduit it may not meet electrical code requirements. I have looked at the NEC and have not found anything that directly prohibits twisting the hot and neutral conductors together and then pulling the twisted pair in a conduit. That doesn’t mean it isn’t in there somewhere though. Bottom line, is it allowed by the AHJ (Authority Having Jurisdiction) electrical inspector in your area? He/she has the final say. Period.

Jim
whart
1,252 posts                                                                      09-27-2017 2:17pm

If you look for an electrical contractor that does commercial work, not just residential, you may already be in the ballpark in terms of dealing with some of this stuff (less arm-twisting). At least that’s been my experience. Good luck.
Bill,
I agree.

Jim

My understanding is that Romex (such as 10-2 or 10-3) can be run behind drywall and in attic areas without a conduit.  That is what I found out during electrical code research and that is actually how my house wiring is ran.  My house was built in 2000 in California.  Your local electrical code might be different.

The way I understand it, is if you use individual wires (such as TFFN/THHN copper), then they have to be run through conduit all the way. 

10 awg romex is the best in my opinion.  I think you can get larger (such as 8awg), but they are stranded.  10awg is the largest solid-core you can get.  Other people have written that the got better sound quality using 8awg or 6awg wiring to the outlets.

If you choose 10-3, you could use 2 of the insulated conductors just for "HOT" (giving you 7awg for the hot conductor).  Though, I don't know why you would really need this unless you had something like a huge Boulder amp that required a 30A circuit.

If you want to get better wire and are willing to spend more:

Audio Sensibility sells both 10-2 and 12-2 cryo treated Romex.

VH Audio sells cryo treated 10-2 Romex.  They also have a pre-burned-ind (COOKED) 250 foot roll of 10-2 Romex for a little bit extra money.

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