20 Amp Circuit Design Basics


#1

First, I will call my state and local Electrician inspectors to inquire if they have an audiophile working in their office who will advise.

My objective is to treat my new Stellar PreAmp, M700, DSJr and PW CD player to a clean power source. I haven’t experienced any problems like noise or hum or other. I have 2 Dectet power conditioners for surge and lighting protection; and, don’t intend to add a regenerator. I am content with the way the system sounds, I just want to add something new.

My question to you is, please advise specifics for a dedicated 20 AMP circuit for my audio equipment. I will include one Sony 55" TV monitor. The system will always be 2 channel.

So far I have thought of these few requirements:

Unbroken run from breaker panel to outlets.
12 gauge wire
run wire in metal conduits and metal outlet boxes.
PSA receptacles (5)
PSA noise harvesters in each receptacles.

Please edit my list and add your recommendations, thanks

Chas


#2

I’d consider doing two or more new circuit since the additional cost will be small compared to the overall labor. In my previous house I initially did two outlets and later added four more (but I have a multichannel system with monoblocks.) I’d recommend 10 gauge wire (tho fewer electricians like working with it for things like this.)

In order to meet code and conform to your wishes your installer may need to get creative. In my new house we had to do things like having a subpanel right outside the music room to transition between the flexible conduit running inside to the outlets and the conduit that runs outside back to the main panel. The subpanel doesn’t have any guts, and the wires run straight thru with no splices, but (at least here) the subpanel was required by code. We took advantage of the subpanel to tie all of the safety grounds together and ran a single (huge) ground back to the main panel. That can lower ground noise (and ground loops) a little.


#3

Many thanks Ted,
I will use 10 gauge. Regarding the number of circuits and number of outlet combinations. Is it better to have more circuits and less outlets per circuit? Given my modest needs, I only wanted three outlet boxes but decided to go with 5. The old 15 amp circuit will remain for lights, laptop, air purifier, humidifier, fans, etc, I will consider adding a sub panel, paying close addition to the grounds.

.


#4

I don’t have any concrete data on one vs more than one dedicated line, but it’s nice to have the option of, say, separating digital from analog, or having a spare one for testing a new component without unplugging a current component, etc. I don’t think I’d try to have one for each component so a modest system probably doesn’t need more than a couple of lines and even just one line should be noticeably better than none.


#5

Some additional thoughts…

BTW, PS Audio’s recommendation: https://www.psaudio.com/ps_how/how-to-install-a-dedicated-ac-line/

IF possible, I also recommend installing the circuit as a dedicated isolated ground (IG) 20 amp with a quad faceplate (AKA Double Duplex). The cable required for IG is a 4-conductor wire. 10 guage is preferable but 12 is required (larger number is thinner and more resistance… counter intuitive).

With regard to isolation grounding, talk to your electrician if this is at all possible. My knowledge ends here but I understand you must have a special, commercial-grade breaker panel to install true isolation grounding. You can recognize an installed isolation ground circuit … they are common in hospitals… they have a little triangle stenciled to the socket… and usually orange. I was fortunate that in my last home was a converted commercial space and had commercial panels… So I had my electrician run a few dedicated, 20 amp, 10 gauge, isolation ground circuits to a few places. Dead silent!

I also understand these IG sockets are different in how they grip the plug… or just get a “hospital grade IG quad socket”.

Dedicated means there is only one wallplate for that cuircuit breaker… a single run of cable.

You must tell the electrician what you want exactly because the cable type can drive up your cost quite a bit… you see the electrician just may not stock this stuff and have to buy a whole spool. The guy used said he could not do it because of the cable… then he called me back and said he could… I think he called around to his friends or whatever and picked up the needed length.

In my experience, having a single, dedicated 20 amp isolated ground circuit to power all your audio rack is preferable than multiple circuits to avoid ground hum loops. Further, ensure the chassis ground at the wall plate is not shared by any other wall plates and this is ground is “home run’d” back to the box (it will be this way by definition of an IG).

Just the other day, I powered up my piano keyboard, my amp, and equalizer to play and immediately heard a hummmmmm… I looked down and I had plugged the keyboard into a second, side-by-side wallplate. Each wallplate was a separate circuit (each on a separate breaker back the common panel). I unplugged it and moved it to the same dedicated circuit and the hum stopped.

Cool fact: The North American power grid is 60HZ AC… why is this cool? 60HZ is B-flat. You can tune your guitar to the buzz of a fluorescent light. (actually it is just slightly off, but darn darn close enough!)

Peace
Bruce in Philly


#6

10 gauge wire for sure with high quality outlets. Give some thought to adding a regenerator. I have a P5 and a Quintessence (P12 is on order). Both measure 1.7% THD power being delivered to my 120 VAC system. I have very stable power. THD out is .1% on the P5.

My dedicated 20A circuit using 10/3 wire, PS Audio Power Port Receptacles (Quad) and Noise Harvesters. IFi makes some power products you may wish to check out as well.


#7

Thanks many times to all, I am very grateful. I will share your thoughts with my electrician. With your input, I am thinking: two circuits one for Digital and the other for Analog. I will use a quad receptacle in both circuits I am assuming they will be considered as one wallplate (let me know if this assumption is not correct). With 10 gauge IG 4 conductor wire, I will discuss carefully with the electrician.

In the future, after an AN1 speaker upgrade, I will consider a regenerator for each circuit. I think it might be overkill for me, since my system currently exhibits no noise or hum. I admit to having less critical and demanding ears than purists; and I am very impressed with my PSA components. Yet, I am gadget oriented (please excuse, no slights intended ) so adding these circuits does have great appeal to me.

On further reflection, If I add a regenerator does that offset the need for a quad receptacle? Something for my further consideration .

Again, thank you to all,

Chas


#8

To quote the electrician who re-wired my house “You can’t have too many outlets”. The cost difference between a duplex box and a double duplex is negligible. Same goes for the faceplate and the small additional amount of wire to connect it all together in the box. The only “real” expense difference is the second duplex outlet in the box if you’re talking hospital grade or audiophile outlets. Leave room for expansion. You never know what gadget tomorrow may bring :slight_smile:


#9

The consideration of 2 circuits, one for analog and the other for digital, has strong appeal to me. My question is, the DAC (DSJ in my system) input is digital and its output is analog, where to plug this component, into the digital circuit? But I am curious about this choice, any comments, insights. I will use the XLR connects to the preamp.

Regarding too many outlets, I am wondering if grounding is a big primary consideration in the number of outlets. I just learned that each circuit should have only one outlet. Is this because you only want to cut the power feed once and that cut is at the receptacle? Or is the grounding connection the most important element of the circuit, so only one cut?

If I add a power regenerator(s) for my 5 components, 6 max, do I need more than one or two outlets because all components would plug into the regenerator. And would that also answer my grounding priority concern? (I would add a second circuit for the 2nd regenerator.)


#10

Waayyyyy… over thinking this.

First, IMO, all your electronics, digital or otherwise should be on the same circuit due to the greater evil of a ground loop. A 20 amp circuit is a ton of power. As I noted above, I personally experienced the evil of splitting across circuits just last week so… believe it or not, your call.

2, I can’t believe why a quad is different than a duplex… look, I am an audiophile nerd since the mid 70s… I get it… do it right, sweat the small stuff… but quad vs duplex… well you get my opinion here. That is simply silly in my book. A quad just gives you more outlets should you need it one day… incremental cost is insignificant…evan-K has it correct.

Go ahead an put in two circuits, split the load and if you think it sounds better that way, you win.

BTW, cheapest I have seen for a short run is $250… expect $350… if you live in a special zip code, you will pay $500 and up… depending how clueless you are. Sorry, don’t mean to insult anyone here, but the people in my zip code are all dopes… they get ripped-off hourly. I think I am the only person within a 10 mile radius with automobile jack-stands and tools who actually can turn a screwdriver.

Regarding the load capacity of a 20 amp circuit… 20amps X 120 volts = 2,400 watts available (ohms law). Then, as a rule of thumb, don’t load a circuit beyond 80% so 2,400 X .8 = 1,920 watts available. Now look at the specs of each piece of equipment and it will show the power consumption (this is a non-real world max… real world is much less). Then just add up the power consumption specs for each.

So DirectStream DAC = 30W, A BHK 250 amp (a monster) consumes 850W at 8 ohm… (these are non-real-world number… real is way less)… so now we are at 880… and you have 1,920 and that is at 80%… said another way, a 20 amp circuit could kill Godzilla. For 15 amp circuits, just substitute 15 for 20 and rerun the math, So for all you 15 amp wimps out there, fear not, your cuircuit could still kill an entire invading army of Japanese monsters on any Saturday afternoon.

Now a big evil is not-having a dedicated circuit… that is IMO the biggest issue as noises from say an electric motor or dimmer, or Her hairdryer… dedicated can help (but only helps) and IG gets you way further from noise, a PS Audio regenerator makes life nice… owning your own Nuke plant is really where you want to be.

Peace
Bruce in Philly


#11

BTW, that first diagram I posted … I think it has an error in it… it denotes the cable as being 12/3… that means 12 gauge and 3 conductors… IG circuits require 4 conductor cable… So much for yanking a JPG from the 'net.

Same for listening to some guy on the 'net posting in a forum. If you want to know what I do for a living, well I am a canine brain surgeon. No really… I am a canine.

Peace
Bruce in Philly


#12

While not entirely agreeing with everything bruce-in-philly is saying, I do agree that you are over thinking things. Trust your ears, try plugging the DS into each outlet and use the one that works best for you. I suspect your system will sound best with the DS on a different circuit than the analog components in your system. But try both and see for yourself.
Re groundloops, I do take them vary seriously, but that’s precisely why my system has the dedicated circuit grounds all tied together right at the listening room with a single safety ground wire back to the main panel. My system has been hum free from the first use (well, I had to add an digital isolation transformer (or use TOSLink) between the satellite receivers and the AV preamp/switcher, but that isn’t because of dedicated circuit grounding but instead because satellite receivers connect the satellite ground to the phone ground to the AC panel ground and hence ground loops…)


#13

Ted: Always Wise One…

Yes trust your ears. Regarding my experience with a ground loop last week… this does not mean you will experience the same… there are too many variables. My keyboard amp, the Adcom, is really old… maybe it has a leak problem… the wiring in my house that I did not install… maybe there is something goofy there. The transformer at the pole, well how much moisture is in that thing? On and on…

I do feel strongly about the concept of clean power. I had hum issues when I lived in Center City Philly … a Tice Power Block cleaned it right up. I also would get voltage sags that would cause my VTL monoblocks to go into oscillation (figured out by a Conrad Johnson engineer… VTL was clueless) so now I use TrippLite LC2400 peppered around my house for all my audio/video/computer gear. The LC2400 provides filtering and a fairly constant voltage… data center guys love em. While I don’t think their voltage control is as fine as I would like (I exchanged some emails with a TrippLite engineer), it is fine for protection. When I work from home, those relays trip back and forth at least once a day so I know my power is not clean.

So… why don’t I have a PS Audio re generator? Simple: cost. But like all of this stuff, you choose what mole you want to wack this year or … not.

Peace
Bruce in Philly


#14

I meant to also say that there is almost always more than one right answer to a problem (tho there are a lot more wrong answers :slight_smile: )


#15

Yes, I am overthinking, but nicely schooled by this forum. Admittedly still thinking, but no quads or Nukes for sure. Since I have experienced no listening problems with my PSAs, I am going with one circuit.

Since our last posts, I recalled that the AN1 speaker will be powered. I reread Paul’s comments on the ANs and separate subs; and decided that the speakers need not plug into a regenerator. So I will run them through my Dectet for surge and lighting protection ( a big concern for me). Regenerator will be added in a year or two, after new speakers.

This forum is so valuable, I really can’t thank you all enough.


#16

Ted, I believe your last comment was to stimulate my over thinking. You have a great sense of humor.


#17

Do you find that you spend a lot of time worrying that you over-think things?


#18

Yes, you know me. But, I do have fun while I am at it. I probably will have more questions, coming from an “inquisitive mind”.
My continued thanks to all,
Chas


#19

I think all the info given is excellent but I did not see any mention of two things that in my experience have made a difference in my installation. My first dedicated line was two 20 amp circuits using (6)-10 gauge stranded copper conductors. I can not quite explain why but the overall sound was less than optimal it always had a mistyness to it. My second installation used (6)-10 gauge solid copper conductors where each conductor is cut to the exact same length, with each circuit consisting of 3 wires (white, black and green). These three wires are twisted with a drill and the two pairs of (3 conductor wires) are pulled in a 1" conduit. The reason for the critical length is to prevent potential gound loops. Both ground and neutral wires should terminate on the respective busses as close together as physically possible. The twisting of the conductors provides a bit of noise rejection. One of the dedicated circuits is for all digital equipment, and the other is for all analog equipment. This install is dead quite with no mystness. Has any one else experienced any difference between solid and stranded conductors? Has anyone else used twisted conductor pairs?


#20

There’s definitely a positive sonic difference between solid and stranded, I meant to mention that earlier: but some installers don’t like to work with 10 gage solid conductors, especially with multiple bends in a conduit.