Dedicated Circuits - Subpanel importance?

izjjzi

Does a subpanel help? Is it required? ... Perhaps if I can independently ground the subpanel it might make a difference?

There's no advantage to a subpanel, imo, unless perhaps it can be located close to your system and simplify the rest of the install. As for grounding, all grounds must be bonded together at the main panel and only at the main panel to ensure a fault to ground will trip the breaker.

I have also done my own electrical work with good result. I do recommend getting a permit if required (it was in my case) and then having your work inspected. It's cheap insurance.

There has been a lot of audio chatter about grounding.  Michael Fremer did an extensive electrical upgrade and has a YouTube video that may be helpful.  I have an audio friend that also did a sub panel addition as well as install a new ground system for his home.  It was based on a three rod grouping that went very deep (30 feet) into his rocky soil to get the resistance as low as possible.

Does a subpanel help? Is it required? Subpanels are typically supplied from a breaker off of the main panel’s bus, so I’m guessing there is no advantage in terms of SQ? Perhaps if I can independently ground the subpanel it might make a difference?

The big advantage of a subpanel is the heavy gauge wiring to the main panel as well as the convenience of short local circuits. The heavy gauge will reduce any possibility for voltage drop that you would get from running 12 or 14 gauge wiring given the same current.

Always follow the National Electric Code for grounding, which means NO independent ground.

Do put in a panel surge suppressor on your main panel and sub panels.

I see 2 possibly 3 code violations in your questions maybe you need to rethink your don't need an electrician stance. At least pull a permit and get inspected unless you never plan on selling the house. Forget insurance covering fire damage.

@djones51 Can you PM these potential violations or post them here? 

@All - Based on your responses the subpanel would reside right next to the main panel, so I do not see any advantages vs a pair of 20A breakers in the main panel. There is plenty of room. This simplifies things and I will look into a permit and inspection. Thank you.

The backstory here, which I may have mentioned in another thread, is that I learned "the hard way" of how important a dedicated line may be. My system was sounding pretty good, but I was listening alone during the day and at night. My brother visited twice and loved what he heard. My point - my system was the only thing using electricity during these times, something I didn’t realized until last Thanksgiving when we had a houseful of guests (as did the neighbors) and my brother said to everyone "you have to hear xxxx’s system". Practically every light, television, Christmas lights and tree were on at the time and a number of us headed down. The SQ was atrocious. Embarrassing! My brother walked out blaming my gear and exclaiming "what a waste of money"... A total disaster I want to avoid or greatly mitigate in my next system.

Consider a Furman with LiFT and SMP.  Living in an apartment until recently I always could hear when the Furman was missing from the system.

Before you go to pull a permit for the electrical, you need to know IF you, the homeowner, can legally do the electrical work in your state.If not, you cannot even get the permit. Some states require a licensed electrician to do any and all work. I know the state of MD used to be that way. Don't know what other states have the same rules. I'll leave it at that

A sub panel is great for adding shorter runs. It add 220/240 if you want. I use it on my bass amps.

Romex is for running on it’s own. No conduit. There is flex armor that meet code in the bay area.

# 10 is great for a subpanel feed

# 12 for 20 amp circuits

# 14 for 15 amp circuits

Use copper not clad they sell that crap everywhere. COPPER, not cryo anything just Copper romex or if your going to use conduit use the correct wire for inside conduit or Flex armor. BTW a lot of the new flex armor is aluminum with copper clad..

ALL grounds must be tied at the main

Any breaks in runs must be put in a box

ALL boxes must have a 2 hour fire rating

It’s actually easier for me to run the wire in the wall after it’s all said and done. You just have to ask someone that knows how to string wire without tearing up the whole house. It usually involves a couple of fancy drill bits and just a little patience. Time wise there is an increase but only because of drywall mud setting. I’ve used hot set mud and only had to primer and paint, still a 2 day wait.

PERMITS: Permits mean you bought permits and paid for something. It doesn’t mean you got anything for your money. The home, building or any thing else could burn down and take out half the neighborhood and the inspector is responsible for absolutely nothing other than looking (if they do at all) and signing the little box. My neighbors house was worked on by a contractor, signed off on by the city and caught fire within a year.. THREE issues all via inspection after the fire. All boo boos, caused an electric mickey mouse clock to burn the joint up. You can get a loan easier for selling or buying if you use OPM, I don’t. Pretty simple.

Sell a house or buying one, I pay cash. I buy "AS IS" I sell " AS IS". I have for 50 years and 22 pieces of property. Same goes for most of the people I deal with, unless I carry the paper or something.. We both shake hand call each other suckers and wait until the next time we meet.

Regards

No sub panel needed, although doesn't hurt. Grounding is perhaps most important aspect, grounding rods, no cold water pipe grounding. I also individually ground all my dedicated circuits, exact same ground wire length so no potential issues.

@artemus_5  I started the online permit application and it accounts for homeowner work. I stopped filling-out the form and booked a few quote calls with local electricians. I know what it will cost me to do the work and I will contrast it to a few quotes. I did get one quote for a single run in December of $800 that did not include mention of materials used. I know I can do it for less and why I've considered it. 

@oldhvymec Any chance you live in MA? :)

1. A subpanel just adds joints. I would just run heavy wire from the main panel.

2.  Conduit is a great option if you can handle the aesthetics.  You don't put romex i conduit.  Pull individual single 10 ga wires.  

3.  are you thinking metal clad instead of conduit?  Either is fine.  You really just need to meet the building code.  I don't think either affects how the power will support good sound.

I just installed (finished on Friday) a 30 amp 240v dedicated circuit for my stereo.  I did it inside the wall and ran 10/3 romex.  Everything is 10 gauge all the way to the outlets (both 120 and 240 volts).

Jerry

@izjjzi 

Hey, I'm not trying to ta;lk you out of it. My thought is that if it is illegal to do, then you have just waved a big flag by trying to get the permit. I' with Oldhvymec about permits.BTW I did my own too, but its legal

It is legal here as well.

My plan before starting this thread was to purchase 10,2 romex and run it through wall-mounted conduit to an audio grade outlet. I would use a 20A breaker matching the rest in the system as you should. 

I think MC is the one who suggested metal-clad 10,2 because the metal casing would reduce interference, noise or other...? I hoped to drill into this more to see if I should entertain it..

I think the only benefit of a subpanel is if the main can be split. This way you are not subjected to the noise of a shared common / grounding bus with the rest of the house. In fact, it is no longer a subpanel in this configuration. However, I would NEVER entertain splitting a main line. 

I have 3 electricians calling me tomorrow. Looks like they are video calls where I can walk them through my ask. I will follow-up here with the result. Hopefully others can learn from whatever comes to pass. Appreciate all of the input!

 A subpanel just adds joints. 

I agree with Carlsbad's above statement!

@izjjzi,

IMHO, I would run a 10-3/AWG BX/MC cable with solid copper 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 on AC power lines/branch circuits.
Downside is BX/MC cable is pricier. I would run at least two dedicated 20 amp lines for audio. I have four in my audio rig. All four dedicated audio circuits are 250 volts 20 amps with no noise or ground loops. Also, all four dedicated audio circuits are at the top of the breaker panel numbers 1-8. See the links below. Hope that helps. Mike                                                                                                                        https://healthybuildingscience.com/2013/01/15/residential-wiring-best/#:
 R

 https://www.msbtechnology.com/faq/house-power/

Separate ground for subpanel is against code,  you need to run THHN in conduit not NM and can be run lower on the wall when used in open area.  BX/MC can't be run where it could be damaged, usually it's run high in corner of wall and ceiling and needs to be attached more than conduit. 

Thank you, everyone for the humor and solid advice. I literally chose to spend my time posting here today instead of running to home depot with my shopping list. Thankful I did. Eager to speak with the three local electricians tomorrow.

It's because I caught the audiophile bug that I am looking to save pennies everywhere I can, but maybe this isn't the place to save despite my experience. 

If your panel still has a couple of extra spaces, run 2 dedicated circuits from them with the appropriate breakers to your system.  You don’t need a wire encased in metal. The ground at the panel end goes to the ground buss inside the panel.  The other end goes to the ground on the receptacle in the audio room.  Why make it harder than it needs to be?  I have 2 circuits like this for 23 years with zero noise and zero problems.    A licensed electrician did all the work.  

The way I understood he doest want to or cant go through the wall/walls so running regular NM isn't an option. I would run metal conduit or schedule 40 with THHN since it will be exposed. I could have run mine as well but I got an electrician to do it when I was having other work done. He pulled the permits and saved me the headaches. 

I work for Space X, stuff keeps blowing up. What's your point? Picky! and it's not suppose to blow up? What kind of fun is that?

Party poopers

I usually like to have @jea48 in these threads because he really knows the NEC and your local code may add more.

On the sub panel issue, I did add a sub panel with a copper buss bar to set up what amounts to a separate subsystem for the hi-fi.* Additional connections notwithstanding, it was a fairly long run from the main panel and adjacent new sub panel up to my room. That was connected via 4 gauge feeder line (I had the electricians install a 10kVA isolation transformer) and the run via 4 gauge eventually terminates in another small sub panel in a room adjacent to the listening room, where 10 gauge Romex was used for multiple dedicated lines to hospital grade Porter Ports from good ol’ Albert (I don’t think he has them anymore). All ground tied back to the main household ufer, as others have mentioned.

They did have to break sheet rock to run the dedicated lines but it wasn’t that big a deal to patch and paint. FWIW, I had Romex in a conduit in a previous set up and it was a disaster- noise on one line (from an air compressor for my tone arm) was transmitted to the system given how the lines were bundled. I think each install presents its own challenges. Even if you are doing your own work in a jurisdiction that permits it, it might pay to get a consult from a solid electrician. I lucked out this time (not the first time I’ve done a dedicated room) and got some commercial electricians who were willing to do residential work as well. Went very smoothly- no issues since this latest installation in 2017.

I have always pulled permits for this stuff and where I am now-- Austin-- is permit crazy. I’ve seen wiring out in West Texas that was absolutely frightening, I figure out in the country, they probably have a guy who does triple duty- Justice of the Peace, funeral director and electrical inspector. :)

______

*This will also help me cut out the hi-fi from the eventual install of a Generac to avoid the problem Fremer said he had with the ATS creating noise on his system even when the generator was not operating. I have no need to play the system when the main power is out, but I'll be able to route to the hi-fi subsystem first, then into the main service panel which will tie to the ATS for the generator system. 

My thoughts.

First off if you are going to run more than on dedicated circuit make sure they are both on the same side of the 220. Of not it sounds bad. I have seven dedicated circuits in my main listening room. The other things I did was they are all 20. Amp circuit s. I also made sure that every wire was the exact same length. They all have furutech top of the line plugs on them started with industrial grade 20 amp plugs and there was a huge huge difference going to the badboy furutech plugs. At three hundred Canadian a piece it was one of the best HiFi spending I ever did. I also braided the powerline s around eachother to cancel out Rd and EMI. I had open walls so everything was buries in the wall. After that was in placee 5/8 OSB then a layer of 5/8 fire rated drywall much more dense than regular 1/2 in fact it wieghs over twice as much. 

 I should have double layered that but didn't. I stall have very strong and stuff walls. I have the studs and the ceiling all stuff with Rockwood insulation. The back wall is canted one inch in seven and a half feet. And the corners are cut off at and able at the back wall as well. Had the ceiling sprayed with acoustic popcorn ceiling. The wall diffusion and some suction in a very few places. Enjoy and remember when you build something you have to be prepared to realize you made a mistake and start over. You can groove wide thick baseboard to hide wires behind to move power around the room. Also make sure if you run wires down a conduit that the twist around each other some long runs that are parallel are bad. 

Regards Tom

I ran 10AWG stranded for my Audio only equipment using flexible Armored Conduit (AC) cable that my local electrical supply house provided me. He sold me the stranded 10AWG separately for the AC cable. What a pain in the Ass to fish 3 wires (H,N,GND) through about 70 ft. or so of AC ! But with a Fish Tape, I "got ’er done".

Installed a 20A Breaker at the panel for the Audio Equipment along with a Tripp Lite powerstrip (also 20A) into a PS Audio Receptacle. Ran another circuit 12 AWG AC solid conductor 70ft. run f(also 20A) or just my Computer Equipment, TV, ISP Modem/Router/WiFI box, and any other Computer peripherals.

Strangely, I had a recent power surge which took out my BAT VK50-SE Preamp (sent to their factory already). But NONE of my other equipment was affected. The Preamp was turned off as was everything else except the PS Audio DirectStream DAC and the Bluesound Node 2i.

No power regenerators or conditioning and my AC line is as quiet as a mouse. Maybe I’ll build a Balanced Transformer one day. But for now, I’m happy (until the BAT went down) :-(

@rajugsw , power surge took out your preamp and didn’t trip the surge protector?

I am retired with 30+ years in the electrical field. I do not claim to know everything about anything, yet I have answers to all of your questions. Please PM me if you are interested in discussing this further. My background started in residential wiring in the 1980s and retired in the Power generation and transmission field. I also have worked as a hobby doing home theater and 12vdc installations in my free time since I was a young buck at 14 years old. I am hesitant to post in the thread as every big brain will comment, most of which have no clue will want to argue or debate the topic. There is no debating the physics of electricity or proper grounding. Several questions need a yes answer before investing in power supply isolation is discussed. (Type of service entrance, proper grounding being most important in multiple A/C panel installs, bonding, provider voltage drop +/- up to 10% is allowed and set by your utility provider, not the national electrical code.

With Respect,

Grizz

Chad Allen Braden

IBEW Journeyman wireman, power station electrician, certified C & I tech, Electrical shop owner, and so on. I am not an engineer at a desk, I have hands-on knowledge of installation and maintenance. I would still be working if not for being chased by the reaper due to an untreatable nervous system disorder.

ldandslow

... provider voltage drop +/- up to 10% is allowed and set by your utility provider, not the national electrical code.

Where I live and in most US states electric utilities are regulated by a Board of Public Utilities or similar entity. The board sets standards, not the utility; the NEC has nothing to do with it. Household voltage in the US is typically spec'd at 120VAC ±5 percent, and a utility must conform to the standard. To be clear, it may not be an easy matter to get a utility to provide the service as required, but it can be done.

So many words, so much misinformation🤔

• Romex offers very good magnetic field suppression
• Twisted wire offers very good noise immunity
• Loose wires in conduit is poor and essentially a radiating transformer
• No current should flow in the ground and if it does there is a problem
• Earth Safety must only tie at a single point unless an engineered solution is installed
• A single over capable current circuit is better than two as two will contaminate each other unless pains are taken to ensure otherwise
• Peak current is far below what will trip a 20A breaker for most home systems
• Breakers will run @ 100% forever, 150% of trip value for a long time and close to 1000% for about a second
• A soft start system control can mitigate power on surge. Ditto sequenced power on.
• Musical peaks are not in phase with the line
• Peak current at full breaker rating drops less than 0.2dB across the AC line over about 50 feet
• If you install two circuits be certain they are on the SAME Phase and on the opposite phase to the noisy stuff. You may need to rearrange the panel, depending on the existing layout. High current things like stoves and dryers are low noise while aircon is higher. Dimmers can play havoc.
• Single breakers opposite one another in a panel are one the same phase. Single breakers on the same side and below one another are the opposite phase.
• IF you are capable, significant system wide noise reduction can be effected by paying attention to the line phase in the electronics
• Ensure the Line, Neutral and Earth Safety connections are pristine all the way to the meter

See Microsoft PowerPoint - Indy AES 2012 Seminar w-Notes v1-0.ppt (wordpress.com)

I viewed a video of someone wanting "dedicated" circuits installed into his listening room as you are.  I felt a sense that the electrician that was doing the actual work understood the Audiophile's direction and wants.  Find that such electrician.

Great feedback as I had hoped! I will be PM'img a few of you, hopefully soon. One electrician wanted $100 just to give an estimate. Nope. The other two were in the same ballpark, which is like fives times the cost of materials alone. They were in sync as well with what they would do, which is run a line to s small subpanel in the listening room with x number of lines (equal in-phase) to x outlets. The breaker for the subpanel would be at the top of the stack in the main panel, with other breakers moved to the other bus if they have noisy end points like dimmer switches, appliances, etc. i now really want to do this myself because there is nothing complicated about it. Going to take the week to think it through. Thanks again.

No need for a sub panel. All you need to do is use a piggy back breaker in the existing panel, if you happen to be short on space. If enough room, then add a conventional 20 amp breaker and run 12/2 romex to your receptacle of choice. I chose Audioquest’s Edison receptacle. I believe in synergy, and so I also run a AQ Niagara 1200 into that receptacle along with AQ power cords. The sub panel will not make any difference In sound quality. If your hifi is on a seperate circuit as above, you are not going to get noise from an appliance on a seperate circuit. I don’t care what anyone else tells you here, it’s bull. My breaker for my hifi sits right next to a breaker that controls a fridge, no noise on the hifi circuit. You are making it way more complicated and expensive than it has to be. All you need is a 20 amp breaker that matches what you already have in the main panel, and a high quality hospital grade 20 amp receptacle, be it a home depot or Lowes product or an audiophile receptacle such as Audioquest, Furatech, or oyaide. Lastly, a run of 12/2 yellow romex...no need to run 10 gauge...too stiff and hard to work with. You want to get real fancy, add a RFI/EMF receptacle cover plate by Furatech.

Use Romex cable, unless you have a rat problem, then use metal Clad or conduit. This project is quite simple and not expensive. Black to breaker screw, white to neutral buss bar,  ground to ground bus bar. Heck, I did it with the power on., not recommended. It helps that I took electricity in Vocational school. 😁

@lowrider57 Yes and the stupid thing is I have a soft start circuit board that I bought (and tested) off of eBay which is residing inside an incomplete Amplifier project that I’m working on. I’m sure if I would have “Jerry rigged” the AC power between it and my BAT Preamp, I still be listening to the eight 6H30 tubes that reside inside the BAT.

Lesson learned (I guess). The internal fuse I’ve never changed or looked at since I bought it 1.5 years ago.

If the fuse is the wrong amperage, that too would explain a lot. When I checked the fuse, I only checked for continuity, not it’s Amp rating. Stupid me :-(

Damn good question though.

If your hifi is on a seperate circuit as above, you are not going to get noise from an appliance on a seperate circuit.

We must have imagined moving the breaker to the other leg curing the noise.

@ieales

Unless the OP has a 3-phase system (unlikely), don't you mean "leg"?

'Leg' is synonymous w 'phase'

A home 120VAC panel is fed from a center-tapped transformer.

The Neutral, connected to Earth, is the center tap. Each leg of the panel is connected to one output of the transformer, which are out of phase.

The two legs of the panel are out of phase with one another.

There's no advantage to a subpanel, imo, unless perhaps it can be located close to your system and simplify the rest of the install. As for grounding, all grounds must be bonded together at the main panel and only at the main panel to ensure a fault to ground will trip the breaker.

@cleeds , I've learned about grounding code from forums such as this. But I've been wondering why can't a subpanel have it's own grounding rod as long as the main panel has a grounding rod? This is unclear to me because the subpanel ground is tied to the main panel grounding block.

Is a grounding rod ever used on a subpanel?

@lowrider57 said:

I’ve learned about grounding code from forums such as this. But I’ve been wondering why can’t a subpanel have it’s own grounding rod as long as the main panel has a grounding rod? This is unclear to me because the subpanel ground is tied to the main panel grounding block.

Is a grounding rod ever used on a subpanel?

You can add a ground rod to a subpanel connected to the ground bar in the panel, BUT, an equipment equipment grounding conductor still must be ran with the feeder conductors and the equipment grounding conductor shall be terminated to the equipment ground bar in the main electrical panel as well connected to the ground bar in the subpanel.

The purpose of an equipment grounding conductor is to provide a low impedance path for ground fault current to return to the source, the utility power transformer, through the service neutral conductor at the electrical service main electrical panel where all equipment grounding conductors are connected to.

If the feeder equipment grounding conductor was lifted at one end the only path for ground fault current would be the earth driven ground rod for the subpanel... The earth is a poor conductor... The ground faulted circuit, be it a branch circuit fed from the subpanel, or a faulted feeder conductor, there would never be enough current to overload the breaker and cause it to trip open.

The main purpose for a ground connection to earth is for lightning protection. I does absolutely nothing for improving the sound of an audio system. The earth does not possess some magical mystical power that sucks nasties form an audio system

So forget adding an Auxiliary grounding Electrode to a subpanel that is located in the same building structure... Lightning loves them though...

FWIW, in a separate detached building, structure where a subpanel is installed fed from a main panel ,say in a house, then by code an new grounding electrode system shall be established. An equipment grounding conductor ran with the feeder is still required, connected at both ends to the equipment ground bar.

NEC 250.54 Auxiliary Grounding Electrodes.
It is permissible provided the sub panel feeder from the main electrical panel equipment grounding conductor is connected to the equipment ground bar in the main electrical panel as well to the equipment ground bar in the sub panel. The Aux ground rod ground wire is connected to the ground bar in the sub panel.

.

.

Grounding Myths

"Electromagnetic Compatibility Engineering" by Henry Ott

3.1.7 Grounding Myths

More myths exist relating to the field of grounding than any other area of electrical engineering. The more common of these are as follows:

1. The earth is a low-impedance path for ground current. False, the impedance of the earth is orders of magnitude greater than the impedance of a copper conductor.

2. The earth is an equipotential. False, this is clearly not true by the result of (1 above).

3. The impedance of a conductor is determined by its resistance. False, what happened to the concept of inductive reactance?

4. To operate with low noise, a circuit or system must be connected to an earth ground. False, because airplanes, satellites, cars and battery powered laptop computers all operate fine without a ground connection. As a mater of fact, an earth ground is more likely to be the cause of noise problem. More electronic system noise problems are resolved by removing (or isolating) a circuit from earth ground than by connecting it to earth ground.

5. To reduce noise, an electronic system should be connected to a separate “quiet ground” by using a separate, isolated ground rod. False, in addition to being untrue, this approach is dangerous and violates the requirements of the NEC (electrical code/rules).

6. An earth ground is unidirectional, with current only flowing into the ground. False, because current must flow in loops, any current that flows into the ground must also flow out of the ground somewhere else.

7. An isolated AC power receptacle is not grounded. False, the term “isolated” refers only to the method by which a receptacle is grounded, not if it is grounded.

8. A system designer can name ground conductors by the type of the current that they should carry (i.e., signal, power, lightning, digital, analog, quiet, noisy, etc.), and the electrons will comply and only flow in the appropriately designated conductors. Obviously false."

Henry W. Ott

 

Who is Henry Ott?
http://www.hottconsultants.com/bio.html

.

BUT, an equipment equipment grounding conductor still must be ran with the feeder conductors and the equipment grounding conductor shall be terminated to the equipment ground bar in the main electrical panel as well connected to the ground bar in the subpanel.

The purpose of an equipment grounding conductor is to provide a low impedance path for ground fault current to return to the source, the utility power transformer, through the service neutral conductor at the electrical service main electrical panel where all equipment grounding conductors are connected to.

@jea48 

Understood. We discussed this when you advised me about replacing my meter box and outside line due to corrosion. If you remember, distortion and DC was entering my service panel.

I think where I'm confused is from comments in threads about using an "independent" ground rod (or 2) from a subpanel or main panel. My take is that these ground rods are not bonded to the main panel. This doesn't sound kosher. Is there any reason to use multiple ground rods spread out in the backyard? Yes, I know earth doesn't possess any magical powers.

The main purpose for a ground connection to earth is for lightning protection. It does absolutely nothing for improving the sound of an audio system. The earth does not possess some magical mystical power that sucks nasties form an audio system.

If only audiophools understood this one thing...

... and adding additional rods may make the system less capable to survive a strike.

The Ott link seem DoA...

Leg is not synonymous or the same thing as electrical phase. Most residential homes in the US are single phase. One phase of 240V is brought from the transformer and split into 2 x 120V. It’s one wave cycle split in two—2 legs of the same phase.

Three phase is 3 different wave cycles, 120 degrees apart.

  I believe what I believe, BUT it doesn't change the truth. It almost depends on which expert you ask about one phase or two going to a residential home. My understanding is this, 1) that if in fact that two separate conductors were run to a panel, but were of the same phase, you would still have 120 volts, but with more possible current capacity.  2) OTOH, if each of these two conductors (at 120 volts each) were Out of phase with each other, Then the DIFFERENCE between them will equal 240 volts. 

 I have heard this discussed more than once, especially at the PS Audio site, which would be damned near a reference for me. 

@lowrider57 Said:

Understood. We discussed this when you advised me about replacing my meter box and outside line due to corrosion. If you remember, distortion and DC was entering my service panel.

I remember the thread. Harmonic distortion caused by a corroded connection in the meter socket was causing a problem with a piece of audio equipment. Wasn’t it a noisy buzzing, vibrating, power transformer?

I think where I’m confused is from comments in threads about using an "independent" ground rod (or 2) from a subpanel or main panel. My take is that these ground rods are not bonded to the main panel. This doesn’t sound kosher. Is there any reason to use multiple ground rods spread out in the backyard? Yes, I know earth doesn’t possess any magical powers.

Independent, dedicated, isolated, ground rods are dangerous. They violate all electrical safety codes.

NEC 250.54 Auxiliary Grounding Electrodes is one of the dumbest code editions ever. All the additional grounding electrodes do is to provide lightning a direct path into a building’s electrical wiring damaging electronic equipment as it goes on its merry way to the electrical service’s main grounding electrode system back to earth. Lightning loves Auxiliary Grounding Electrodes..

.

I have never seen phase used for anything other than the distinction between single and three phase in the NEC. Which is what we are talking about in reference to someone claiming that there are 2 phases in single phase service.

2 phase power is not used anymore.

For something to be out of phase, there must be at least two identical wave forms that don’t line up. In 3 phase power, 3 wave forms are 120 degrees out of phase. In single phase power, one wave form is split in two, but not out of phase.

That's right, @jea48 , it was a large toroidal transformer humming. You answered my query and we discussed what might be causing it before I called the electrician. I'm always appreciative of the help you and others provide. 

Your explanation regarding isolated ground rods confirms what I thought. There have been many electrical threads where the OP has believed that isolating grounds either in the house or in the ground will reduce noise. I know there must be only one common ground but was looking for the final word on ground rods. Many thanks.

Leg is not synonymous or the same thing as electrical phase.

From an electronics standpoint, residential panel legs are 180° out of phase.

Three phase power is 3x 240 volt 120° apart. Apples & oranges.

I believe what I believe, BUT it doesn’t change the truth. It almost depends on which expert you ask about one phase or two going to a residential home. My understanding is this, 1) that if in fact that two separate conductors were run to a panel, but were of the same phase, you would still have 120 volts, but with more possible current capacity. 2) OTOH, if each of these two conductors (at 120 volts each) were Out of phase with each other, Then the DIFFERENCE between them will equal 240 volts.

I have heard this discussed more than once, especially at the PS Audio site, which would be damned near a reference for me.

Believe in the tooth fairy if you like, but ONE phase of the three 240 volt lines is run to residential property. 120 volts is derived from the Neutral Center tap and each leg of the transformer. A lot of PS Audio is bunk!

A lot of PS Audio is bunk!

 And That you can take to the bank. 

A lot of PS Audio is bunk!

 And That you can take to the bank. 

     You can say that again!!

Seems to me, it would be a change in polarity not a change in phase. A change in phase is a change in timing, like in three phase systems.