Dedicated line questions...

Did a search, but can’t come up with a good answer. I am considering the install of a dedicated line. The general consensus is a 20amp circuit. How does this rectify with a full system designed around 15amp components/cords. I already have PS audio receptacles, and have upgraded/cleaned up all the other outlets on the current circuit, but it is still noisy. Would installing a 20amp circuit require a refit of gear or just 15-20 amp power cords? I don’t run big mono’s and really only need one line. Would a dedicated 15 suffice?  Yeah, fairly clueless in this realm.
20A is indeed what you want. How this "rectifies" with 15A components is simple. A is for amps, is for current. In the case of the dedicated line 20A is the maximum safe steady state current draw on that line. It does not mean forcing 20A into everything plugged in. It simply means that 20A is safely available. 

Your components by the way are not 15A either. Not a one of them. Something like a CD player, phono stage or preamp draws only a very few amps. Power amps can draw more but even a very powerful amp comes nowhere near 15A current draw, except maybe for a brief moment when first turned on. One of the bigger power hogs in a room is a home theater projector, which if it has say a 500 watt bulb and runs at 120V then that's about 5A. 

You want the 20A circuit because even though you don't need it in terms of steady state power draw you do want it because music is lots of very brief transient surges and the larger wire handles this better. Also the difference in cost is insignificant. Everything else, outlets, power cords, conditioner, is all the same 15 or 20.
MC, that’s what I thought. Just seeing a variety of plug options etc had me wondering. Simple. Thanks!
I would PM: 
He is most knowledgable on the subject, and should be able to guide you.
Hi there.

Domestic 15/20 amp circuits are a little more flexible than you are thinking. Kind of rare for the NEC.

The idea, I think is that you might want to plug in a couple of 10 Amp devices in at the same time, and that a single 15A circuit wouldn’t work.

As a result, you are allowed to use dual amperage receptacles, which have 1 prong shaped like a T on a 20 A circuit, and connect either 15 or 20 A devices or even far less.

Many devices, like wall warts, will sip off this and may be 0.5A or less. What is important is that the breaker be correct to the house wiring, and that the dual A receptacles be used only on 20 A circuits.

The appliances however may use any gauge of wiring that is acceptable to it’s own fuse/breaker rating. So yes, you can run a 20 A circuit, and put in multiple outlets with T shaped sockets and use 15 A surge protectors on them. If your appliance is rated for 15A you must use a minimum 14 gauge. If 20, 12 gauge.


If you want to get and idea how much amperage your component draws take a look at the ac fuse rating.
Bigger wires = better power transmission.
If you’re doing it, do it right.

Unless you are looking for mumbling.


Definitely will do the 20. No doubt! Thanks guys!

 There is a PS Audio video on YouTube about installing dedicated lines. He uses 30 amp (orange) romex with 20 amp receptacles. Is there any benefit to this? Is it worth the cost difference as 30 amp romex is more expensive. And is there much difference between less expensive and more expensive romex? The cost can vary widely between brands.

Back in the day, early 1990's, when wire was a lot cheaper than today (and I knew a lot less than I know now) I ran mine like this only with even more overkill, 4 ga wire. Which probably equates to 80A. Don't know. Don't want to know! lol!  

Point is I have done this a couple times now, so that I know from actual experience just how much difference it makes. The biggest improvement by far is simply going direct, eliminating all the outlet-to-outlet connections of a normal circuit. This is very noticeable, but in the big scheme of things only about as big as upgrading to a Synergistic Research outlet or fuse. If that. Going from there to larger gauge wire, even monster overkill like mine, is not that much more. For what it costs nowadays, I about had a coronary looking at what copper costs these days. You could probably buy an outlet and a fuse and be way better off. In terms of pure sound quality for sure, and even more so if factoring in time and effort. 

Dedicated lines are more a long term investment kind of thing. If you are going to be there a very long time, and especially if you have long term upgrade plans, then its totally worth it. I have no regrets. But a lot of guys go into it like its some big deal, when really its just one more item on a very very incredibly unbelievably unimaginably long list of things that matter.
More is better? In this case more probably makes absolutely no difference and might even be against code depending on the wiring that is already in place. Unless you have an extremely powerful amp and very inefficient speakers there is absolutely no benefit in using a 20 amp circuit. Everything in the house goes back to the breaker box. Running a separate line dose not isolate your equipment from anything. If you have a noise problem get rid of the noisy equipment and get stuff with well designed power supplies that reject/filter noise correctly. This is audio mythology of the highest order. But, if you want to waste money on feel good ridiculousness that is always your option. 
If I were building a new home or re-wiring my home I'd probably run 20A to my audio receptacle.  But I wouldn't pay an electrician hundreds of dollars to convert my 15A to 20A without a known reason or goal.  I run all my gear into a power regenerator that only draws 500W and and 5.3A.  I have plenty of headroom.  It's all about what you're trying to manage and achieve.

 I believe running a dedicated line to the breaker box for my audio components only, will help isolate them. There are a lot of things that can create noise like the refrigerator and furnace, not to mention compact florescent bulbs. I have had problems in our last house with compact florescent bulbs in other rooms creating hum. We moved to a house in the country and I don't see us moving again. This is it. I now have a dedicated music room, so I want to get the best possible sound.

 I have been down the power re-generator path and have found it limiting. I couldn't plug my tube amps into it, so I could only use it for my front end. And after I got my Ref Phono 2se, I was going to have to upgrade. I couldn't have all my front end gear on at the same time. I sold the re-generator and bought a Shunyata Triton which is not power limiting. I have been extremely happy with that decisions.

The “goal” would be to get an over crowded circuit (11 receptacles, 4 light switches) off of the path. I have no other choice in terms of circuit or placement unfortunately. I pull off one receptacle into a Furman Elite for all my audio with the exception of my TT, but I might be changing that ASAP, so that everything is off the Furman. Problem with that is, I would need a 10ft power cable to accomplish that. But, given what MC mentioned and others, perhaps it’s not “worth it” so to speak. An SQ enhancement would be the bonus, not the end game.
@geof   That's a reasonable goal.  While I use a 15A circuit, it is dedicated to only my audio.
It’s very simple. Ask the electrician to install a circuit to your listening room. What you need:

20-amp breaker at the panel;

Nema 5-20R receptacle on the wall. This type accommodates both 15 and 20 amp plugs. This is what to buy (or something similar if you want a audiophile receptacle):

A wire from the breaker to the receptacle. Use either:
3-wire #10 romex, like this:

or 12/2 MC cable, like this:

Then you’re good to go with whatever you plug in. If the plug fits the receptacle, it’s all safe.


I completely agree, A line for just audio equipment and nothing else. That can't help but be a good thing. Just getting all the extra stuff and connections off the line. A much cleaner path.

I was thinking a total of 3 receptacles. 2 on the side wall for my front end equipment. And one between the speakers for the amp. Plug the amp straight into the wall so I don't need a long power cord to the Shunyata Triton.
I used to be able to hear feedback in my stereo when I turned on lights in the dining room. An independent line ended that.  They do matter, and not just for peace of mind.  I actually ran two to my system which lets me keep my amps plugged directly into the wall while isolating the front end on a different line. If you can afford the wire cost, I'd recommend having the electrical pull the second line too. The added work is minimal and you might find that you want it later down the line. 

Honestly I wish I had three, one for the amps, one for the front end, and a third for anything with switching supplies. The further down the road you go, the more all of these power supply issues matter. In my system it's usually manifested as a greater ability to relax into the music. I clench my jaw when exposed to high frequency distortion and have ceramic tweeters that are more than happy to pass that information along.
One last thought regarding my motivation for 3 lines. I had a switching supply for my minidsp subwoofer crossover. When I unplugged it from the front end circuit I could tell it was injecting some jaw clenching distortion so I moved it over to a standard outlet/circuit. The next time I flipped the dining room light I heard it in the stereo just as I had before installing the isolated circuit. Bridging those circuits even through an ancillary power supply killed the isolation. Just something to keep in mind...
@cal3713 I'd be interested to know if you still have the same noise if you use an iFi power supply
Your 4 lights, 11 outlets is only a little worse than I had. Compared to that one direct line will be noticeably better. If your system is good at all you will hear it. This isn't expensive at all. One 20A breaker, one outlet, however much wire you need. Half the cost will be a Synergistic Blue or Orange outlet, if you decide to go that route. Which I would. Or you can go the Full Monty like me and hard wire right into the conditioner. See that cable coming out of the wall? 😁😁
@erik_squires I do have a 5v ifi ww for a toslink to spdif converter I don't use anymore, I'll let you know if I find the occasion to test it.
I think I need to add a ground lift isolator to my cable line... any recommendations for that? 
... I need to add a ground lift isolator to my cable line... any recommendations for that?
Back-to-back baluns have always worked for me. Simple, inexpensive.
@cleeds... any particular recommendations?
I've done this in 2 homes now in the last 6 months. 2 lines of 10/2 under the house through 50 ft of crawspace, commando style. I recommend assessing how much physical pain you're willing to endure vs how much money your electrician will charge. 
@erik_squires I just pulled out my ifi 5v wall wort power supply to power an spdif jitter reducer. Initially had it plugged into my bp3.5 ultra balanced power conditioner with the rest of my digital and soon noticed some hash in the system while listening to my main source. Moved it to the power strip that's on a standard house line (w tv, modem, etc.) and things cleaned up a bit.

Could be an issue with balanced power, or poor isolation within the conditioner, but noticeable whatever the reason.
Thanks @cal3713 , I appreciate the update. The very serious testing done over at Audio Science Review only measured the DC output, not the noise they could put back into the line.

This answers my question about that!

I do recommend keeping wall warts out of your "clean" power zone, whether by using multiple strips, or by using conditioners with separate zones.

I guess now we know we need to stick to linear supplies otherwise.
I'd be curious to hear what a benchmark smps does. They strongly argue that their switching supply is actually better than a linear one. Like you I have my doubts, but would love to learn otherwise. Who wants to devote an entire line to switching supplies??
I’m going to try a Decware ZLC in my setup and see how it sounds. Part of my issue is living in CO, thunderstorms are a very real deal. I asked Steve a few questions about his ZLC and it seems to be a very nice, well thought out product, that will handle potential spikes. I am also going to install a whole house surge protector. I just think that is a smart idea. It will be a few weeks before I get the ZLC. It will be interesting. I am also auditioning a couple of Sutherland engineering battery phonostages, the DC concept intrigues me and seems like an excellent isolation solution.
Congrats. Please do report back!
If using 3 wire with ground NM sheathed cable, (Romex is a Trade Name of Southwire Co.), make sure the NM cable geometry is where the conductors are in a spiral twisted configuration. Most of what I have seen lately sold in Box Stores is a flat cable, no different than 2 conductor with ground NM cable.

If you can find the spiral twisted and choose to use it for a dedicated branch circuit you will not use the red insulated conductor. Just tape off both ends of the wire. Use the bare wire for the EGC (Equipment Grounding Conductor) only.
The ROMEX 3-conductor cable tested was used without connecting the red extra wire to anything

Does the taped off unused red insulated conductor act as an antenna and introduce RF into the other wires? Beats me.

In the spiral twist of the cable is the bare EGC centered tightly between the black Hot conductor and the white neutral conductor? Hopefully yes. If not when a load is connected to the branch circuit the hot or neutral current carrying conductors will induce a voltage onto the EGC. The voltage on the EGC can cause a ground loop/hum/noise on the chassis of equipment that use the EGC connected to the chassis.

The above link doesn’t address induced voltage onto the EGC by the hot and neutral current carrying conductors.

See page 15
Read pages 31 thru 36. Also read page 39.

Read pages 11 thru 13

I would recommend 2 wire with insulated ground MC (Metal Clad) cable with solid copper conductors over 3 conductor with ground romex.
2 wire with ground MC cable the three conductors are tightly, and I mean tightly, grouped in a spiral twisted configuration. No unused conductor in the mix.
I have read through this post and I noticed some folks here use both lines from the distribution panel.   That is, line 1, line 2, neutral, and earth, such as would be wired when using the Southwire 10 awg, 3 wire.  Since line 1 and line 2 are opposite in phase for North America (and anywhere else where split phase lines are used) that means hum is more likely to occur since the outlets are no longer identical polarization.   If you are using an isolation transformer and feeding it 240 VAC then stepping it down to 120VAC, then this doesn't apply.   But if you don't have an isolation step down transformer, then you might get some hum.   I see the point for 10 awg wire and a dedicated line, but I don't see the point for using both lines without a transformer.   That really is counterproductive.
This is an example of a isolation transformer, step down.  Feed it 240VAC in and get 120VAC out at 2x the current capacity.   This is not a plug in product btw, this is either DIY or look for an equivalent factory made unit you can just plug in.
@spatialking... that is essentially what the Decware ZLC is. I have looked at the reality of installing a line from my breaker to where I need it, and it would be a serious PITA to run new cable to that area. Basically across the entire house, in the attic, through vaulted clients etc. no way to go under... 
It was a lot easier for me to run my dedicated circuits. I ran 6. You don't want to have dimmer switches, or other appliances on the same audio circuit. I live in a log home with a crawl space. You can actually walk in when entering, then it becomes more of a crawl. I ran my 10awg (exterior wire) from the breaker box, 6 20amp breakers, carefully stapled the wire to the floor joist. I had drilled the holes close to the exterior log wall, pushed all the wires through the pine floor, make sure you leave enough on each end. I used Furutech NFC Rhodium outlets. I even soldered the ground connector, and spade connectors as to have a proper contact. OCD all the way! I just mounted the junction boxes to the wall. I wrapped all the wire in black. what you do see has a retro look. With drywall or fishing wire through it would be a lot harder to do! All these things, cables, outlets, dedicated circuits are accumulative. If you have a revealing system all these things make incremental improvements. 
spatialking323 posts


I have read through this post and I noticed some folks here use both lines from the distribution panel. That is, line 1, line 2, neutral, and earth, such as would be wired when using the Southwire 10 awg, 3 wire. Since line 1 and line 2 are opposite in phase for North America (and anywhere else where split phase lines are used) that means hum is more likely to occur since the outlets are no longer identical polarization.

I suggest you reread the thread again. No one mentions using both Lines, legs, (therein a 120/240V multiwire branch circuit), to feed a single dedicated 120V branch circuit.

I think you misunderstood what @gs5556 meant when he recommended using 10-3 with ground Romex for a 120V dedicated branch circuit.

FWIW, 3 conductor with ground NM sheathed cable (Romex is a Trade Name of Southwire) is not designed/manufactured only for use for 120/240V multiwire branch circuits. 3 conductor with ground is also used for 3 way switching of lighting as well as split duplex receptacle(s) switching for table lamps. Top receptacle of duplex is hot all the time, bottom receptacle is switched by a wall switch.
Just run 10awg from a 20amp breaker to a quality outlet. For my monoblocks I only use one inlet per outlet. I'm able to this because I wanted more than enough outlets. I separate analog/digital per circuits. This is not that difficult.
Yeah, in theory it is a piece of cake. Very simple. Unfortunately for me, actually running the wire would be very challenging.
That's the difficult part. As mentioned myself and some others on this thread have crawl spaces that make running the wire a lot easier. I don't know the layout of your house, but I have heard of guys running external 10awg and navigate the wire from the outside in. 
@jakesnak, that would be infinitely easier for sure, and a definite thought. I think I will wait until I get the ZLC in the mix and go from there... good thing is, I already have an outlet on an outside wall, so that could make the entire job very simple. I’m not sure if I would have code issues locating conduit outside the house.
@jea48  I see, thanks for the clarification.   
Speaking of the  Decware ZLC - I see it has line capacitors from line to earth on the secondary side.   This negates the concept of "clean grounds" or "quiet grounds" that some manufacturers use, noting that others, such as Decware, do not follow that concept.   Has anyone performed any comparison tests on this sort of thing?  I'd be most interested in hearing about this.
Most computer / server noise suppression units have caps from line to earth but computers don't listen to music.   I have some commercial ADC noise suppression systems on my stereo system which have the caps, notably more capacitance than Decware's, and I included them in the green energy noise suppression units I designed at work.   But then, green energy doesn't listen to music either!  
If its exterior or underground 10awg (gray color) no need for conduit. It could be tucked up along the skirt of the house, or under a deck, and positioned where no one would see it. Maybe you can find a good place to transition in? Good luck...
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