Dedicated power

My question was about a sub panel on an outbuilding, a grounding rod has to be used here by code as well as the 2 by the service entrance. I know you have to bond the two at the main service, but do you have to bond the one at the sub panel to the 2 at the service entrance?

The purpose of a ground rod is to provide a low impedance path to earth in the event a power line is hit by lightning. All the rods in the area provide an earth mesh.

The Earth Safety is to carry no current EXCEPT IN THE EVENT OF AN ELECTRICAL FAILURE! The fault current is returned to the neutral, NOT the ground rod.

Adding a ground rod will do nothing to cure ground loop noise because the loop still exists and depending on the installation with a different, possibly higher earth impedance.

Theoretically, one ground rod with a 1-inch diameter driven in homogeneous 1,000-ohm per meter (ohm/meter) soil for one meter would yield 765 ohms. Driving it two meters into the soil would give 437 ohms. Going to three meters, however, does not give as great a change (309 ohms). One would get faster ohmic reduction and easier installation by using three rods, each one meter long, giving 230 ohms compared to that of one rod three meters long. This assumes they are spaced “greater than the sum of their lengths apart”.
see https://www.polyphaser.com/News/DownloadFile?downloadGuid=25400030-29fb-4981-862f-c24c4118b556

Adding additional rods can be detrimental depending on rod material, soil moisture and pH. Improperly done, a battery is created which will destroy one rod. Too close and the rod effectiveness is diminished. 

Thanks builder3, I am likely in NEC violation! I do wonder the potential hazard of my set up...and wondering if there will be a sonic advantage/disadvantage to correcting my set up by linking the outlets' ground to the incoming service ground rod. I'm also wondering if grounding to the handy box/conduit is a sufficient ground link. Many thanks.

I believe a sub-panel is required to have it's own grounding rod. One of the more knowledgeable guys will be along, hopefully, to confirm or not.

The one answer I can't seem to find anywhere is on a sub panel in an out building that the neutral is isolated from the equipment ground with a grounding rod, are you supposed to bond that ground rod to the service entrance ground rod.

It can't be additional, unless it's physically tied to the existing grounding rod(s).

You may add additional ground rods to the original circuit however.

Please correct me if I'm wrong, but I believe this is what I have done, the two isolated ground outlets have a shared ground rod which is an additional ground point in the system.  

FYI, You may not use a ground that is electrically separate from your service entrance ground.  Doing so violates the NEC and is a safety hazard.

You may add additional ground rods to the original circuit however.

People may balk at this, but it is my experience.  I ran two 20amp dedicated lines from the first breakers in the panel, everything else on a different leg, 10 ga. Solid core, in conduit, straight run, to the outlet box. Also placed a separate grounding rod for these two lines. While the improvements were vast, noise from all the household appliances, etc. Were still present. The solution was to use isolated ground hosp. Grade outlets sharing the grounding rod. Cleanest, strain free, quietest power I have ever experienced. Art Audio High Current Jota mono blocks on one line, original Hydra on the other feeding preamp, digital sources & analog sources.  I have shared this on a few boards over the years, but never known anyone to take this suggestion.

residential electric service is 240VAC, which is achieved using two 120VAC lines that are 180 degrees out of phase with each other.

They are 180 degrees difference when measured to neutral not each other.

You don’t want the AC line mains voltage bouncing around in beat with the music when pushing the amp hard. An amplifier’s power supply like/needs the AC line voltage steady state.

The power line does not bounce around in tempo with the music. The filter caps supply DC current modulated by the output devices. The line charges the caps @ A/C line frequency. see ieLogical CableSnakeOil and http://192.168.1.160/assets/CblSnkOil/Signal_vs_ACLine.png and Linear Power Supply Design (sound-au.com)

For the umpty-billionth time, PS capacitors charge in sync with the line frequency, NOT THE MUSIC!!! A 15amp circuit with clean, screwed terminals can supply all the current necessary to vaporize any voice coil. The only time the full line current is used continuously is when testing on a load resistor.

If the sound collapses, the PSU is inadequate to supply the required current. Either the caps have high ESR or their capacity is too low.

@OP - If you plan to purchase dinosaur amps, plan to recap them. Otherwise your fat wire install will be for naught. Capacitor technology has advanced considerably in the last three decades.

Two dedicated lines is the way to go. In my case high current tube SET amp benefited from it's own line. Everything else on other circuit with power conditioner, all digital equipment powered by linear power supplies. Switching power supplies inject noise.

jea48, so you're essentially talking about wiring the circuit as 20A (breaker, outlet), but upsizing the wire to #10?  I'm just trying to learn a bit.Thanks

Even without considering any electrical pollution from lights, etc,  it will help.  When I wired the outlet for my system, I used a 30 amp breaker and 10 gauge wirimg.  A second amp really made more difference, but a 20 amp breaker with 12 gauge wiring would have been too little.  Besides, remember: a circuit breaker trips with a continuous 75% load, 20 amp = 15 amp trip setting.  From its label,  add how many watts your amp(s) can draw.  This is the wattage used to fire it up.  If I turn on all four channels of my amps together (subs and mains) not counting preamps, tuners, CD, etc, the potential 3000 watt draw at 120 volts requires 25 amps, more than the continuous trip amperage of 22.5 amps for a 30 amp breaker.  Of course, the regulated power supply helps, but I certainly do not want a 20 breaker that trips at 15 amps, much less a 15 amp breaker that is only good for a continuous 11.25 amps, to be responsible for keeping my ears, and equipment, happy.   AND!  I only have amps rated at 125 wpc (250 @ 4, 400 @ 2 ohms) x4 for my six ohm speakers.

invalid

What's with this on the same phase advice, residential electric service only has one phase it's a split single phase.

In the US, residential electric service is 240VAC, which is achieved  using two 120VAC lines that are 180 degrees out of phase with each other. When someone suggests keeping equipment "on the same phase," they mean connected back to the service panel to the same 120VAC leg.

What's with this on the same phase advice, residential electric service only has one phase it's a split single phase.

I talked with my electrician and local code is I cannot use 20a receptacle on 30a breaker so 20a breaker it is. 
Scheduled to come Monday. 

The only single phase 30amp receptacles are twist lock. If you insist on using a 30amp line you would have to change the male ends of your power chords to twist lock. Total overkill as a 20amp circuit is more than enough or multiple 20amp circuits. They should be on the same phase with dedicated grounds and hospital grade receptacles. 

Just DO IT MAN! You will never regret it!

for the Parasound hca 3500 I wouldn’t be surprised if dealers aren’t telling customers the unit should be fed from a 120V 30 amp circuit. Over the phone Parasound Tech support maybe saying the unit needs to be fed from a 120V 30 amp circuit. I doubt they would put it in writing. If they did they should specify the receptacle outlet would need to be rated at 30 amps.




Doesn't the parasound hca3500 have dual plugs one for each channel?

I encourage the OP to provide 30 amps to the P’sound amp and a separate feed for everything else. “Too much” would serve you better than not enough. I won’t advise on panel connections. I’m gonna follow someone’s suggestion concerning which leg the fridge and chest freezer are on.

An amp having two 15A cords, in some form or another, demands 30A of feed. That said, two pro electricians active on the Polk forum recommend “never exceed 80% of a circuit’s capacity.” My HT will one day have its own breaker panel, another story for another day.
A 30A 120VAC breaker...
https://www.zoro.com/square-d-by-schneider-electric-30-a-plug-in-standard-miniature-circuit-breaker-...

I ran three dedicated 20A circuits for my 5.5 HT. One* circuit feeds the APC H15 that powers and protects all low current devices. The other two** circuits power 6*** amps and 5 powered subs that 4 Furman MP-20s turn one channel at a time. I wish I ran a 4th circuit but I won’t because the current room isn’t it’s final home - another story for another day. *on one leg
** on the other leg
*** adding a 7th amp when I mod/bi-amp the surrounds

I haven’t and don’t plan to finish reading this thread’s comments as it seem there are as many opinions as people offering advice. You have my example that was worth the work.
My best to whatever you decide. Tony.

cakyol
  "Do you have an audio system or a welding machine "?

Well said, and an excellent point. 

Spellchecker. Lol that was mofojo not motorola..

Wow. 30A line will only allow you to draw current past the 20A without damaging wires or blowing fuses or circuit breakers. If you are drawing less than 20A you won't hear the difference with all else being equal.so for Motorola your amp won't "strain" because of lack of power if your amp draws that much power it would blow the fuse or circuit breaker.

Do you have an audio system or a welding machine ?

If you really need 30 amps, you may consider changing your system.  It is more like a PA system than an audio system :-)

Besides, sockets used for 30 amp connections will not accept normal amplifier plugs.

Stay with one line, a 20A. This will avoid ground loops. Just buy a Niagara 1200 and that will give you many receptacles to plug gear into. Also, I’d recommend the AQ Edison receptacle for the one line. So right there you will still have the extra receptacle above or below the Niagara upon plugging it in. Lastly use at least 12/2 (20A/usually yellow) Romex, not 14/2. Do it yourself, it is easy/saves lots of money.

vinylshadow71 posts02-04-2021 7:02pmIsolation transformers bring noise. And eventually they hum.

Extreme isolation transformers don't "bring noise", they are specifically designed to reduce noise, and transformer hum is a mechanical noise that doesn't necessarily translate into signal stream noise.

Isolation transformers bring noise. And eventually they hum. Having surge suppressor devices at your equipment rack brings noise to the system and raises impedance. Use a whole house surge suppressor like a Seimens RS 100 or 140 at the breaker box and a non surge suppressing power conditioner at the equipment rack for the lowest impedance and noise and a higher dump of instantaneous current on demand.

That is Caelin Gabriel of Shunyata’s advice. But a P.I. Audio UberBuss(with a DigiBuss internally to isolate noisy digital components from the analog components) does it better and way less expensively.
Please find a way to isolate the Digital from the Analog.

Then buy a Triode Wire Lab’s High Power Digital American instead of a Shunyata Omega XC and save even more. Take the money you saved and buy new amps like the Jeff Rowland Model 125 or speakers. WIN!

@mofojo:
Run a 10/awg BX/MC cable solid core conductors from the breaker panel to a metal receptacle box. The metal sheathing on the BX/MC cable absorbs the (EF)) electric fields emitted by the wires and shunts it to ground. Now from panel to plug is shielded. The upside is low line noise and reduced antenna effect. Downside BX/MC cable is pricier. Hope that helps. Mike.  

Yes, do run 2 lines.
One for analog and one for digital.

I recently did this. I got better focus on my bass.

As mentioned no need for 30A. Run two 20A lines with 10ga solid copper. Run them on separate legs of the panel. Run the romex at least 12" apart...no staples...use cable hangers.
If the cross other lines have them cross at 90 degrees. Run them to plastic boxes. Use hospital or audio grade receptacles.

Also, when you set up your components, don't run your AC or signal cables parallel to each other. Have them cross at 90. These little things matter.

Running a dedicated line for your system is a major upgrade that does not cost a fortune and the sound can improve as much as a component upgrade.

What most of you big gauge gurus fail to realize is that musical transients are asynchronous to the power line frequency. Low E on a bass is 41.2 Hz. The lowest common multiple with 60Hz is 6180 or every 103 line periods for bipolar supplies and every 51.5 for unipolar.

@ 120 BPM there are 30 line cycles per beat. The power supply is topped up on every line peak which almost never coincide with an audio transient.

Clean connections and no computer junk on the audio circuit solve the vast majority of power problems. Note that many wall-warts for 'audio' devices are SMPS and should not be used.

There's a Torus on HI FI Shark today. For wire use JPS Labs Power in wall cable. It's 10 gauge but probably one of the best for noise rejection.
When I set up my system originally there was noise that you couldn't hear but it did a number on my high efficiency speakers. Brittle is the best way to describe. Very disappointing to say the least. The Balanced Power Technologies 3.5 Sig + introduced was a huge relief. Later found an Equi=Tech 5KVA wall unit. And balanced power doesn't wear out.

@spenav How to wire your house for good power is excellent. It should be required reading.

Adding a whole house surge protector (or go Taurus, etc.) to your to do list something to consider.

We use conduit hard pipe (emt) in Chicago.

Romex has better rejection than loose wires in EMT.
Twisted L-N in conduit it best, but it's a bitch to pull.
See pp 31ff here  Microsoft PowerPoint - Indy AES 2012 Seminar w-Notes v1-0.ppt (wordpress.com)

Well, I think this is overkill, but the suggestion I gave you was exactly what I did for my workshop, running 1 1/2 HP and 2 HP motors. :)

In the basement, the NEC let me run 8 gauge (was it 6?? It was a long time ago) Romex with nothing more than nailed on brackets. No conduit needed. Ran it to a sub panel on a 60 A breaker, and distributed 10’ runs from there.

Could I feel a difference while cutting wood? No... but it was much easier to install this way, and the 4 or 5 dedicated circuits could be run more easily.

Second the suggestion for a Torus or similar transformer. Expensive but the best solution whose installation makes some of these other concerns moot.

@erik,

Run is probably a little over 30ft. Thinking closer to 40ft. 

I’d go twin 20amp heavy gauge shielded lines and use Synergistic Research Orange outlets or hospital grade outlets on up. Lots of beefy ones out there. If you do nothing else getting rid of stock wall outlets should help.

I could not run new lines but once everything from the wall out was ungraded even my wife (who couldn’t care a fig) said she thought the sound was better.

If you go with a power conditioner get a top one.

Thinking of the entire electrical supply and all wires as a components makes doing improvements easy.

https://www.youtube.com/watch?v=fe2nt5BMKsE

Hello, does anyone recognize the silver record weight, Its definitely not he stock weight 
that comes with this Pro-ject Xtension Evo 10 ?
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PRO-JECT XTENSION 10 Evolution Gramofon turntable Plattenspieler - gramofony Pro-ject Project AUDIO VIDEO SHOW PRAHA 2019

How long are your runs?  Unless they are more than 30' you are just as well running 12 gauge Romex.

If much longer, then run a 60A to a subpanel, and then run short 20A circuits to each outlet.  The advantages of a 60, in addition to lower voltage drop, is that the code may let you get away with not running conduit for it. Check your local ordinances.

Never put more than a 20A breaker on a normal 15/20A outlet, regardless of wiring. It has no audible benefit, and serious safety issues.