Power cable

Discussion in 'Audio Hardware' started by Orbe, Oct 5, 2020.

  1. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    For comparison your home's electrical energy power consumption compared to a power plant's available power energy output would be like comparing a grain of sand on a beach. Insignificant....

    As for the AC mains wiring found in a typical US dwelling. The majority of convenience 120V outlet branch circuit wiring in a typical US dwelling is 14 gauge copper good for 15 amps. Is that adequate for an average audio system? Maybe. Maybe not. There are many factors that come into play. VD (Voltage Drop) is an important one. Before I spent several hundreds of dollars on an after market power cord I would first spend the money and have a 120V 20 amp dedicated branch circuit installed.

    Nelson Pass:
    Are AC line-treatment devices necessary? Define necessary. "We try to build equipment that puts up with dirty AC lines," Pass told me. "Our customers expect it, and if they have a problem, we hear about it. We don't design around the assumption that there is AC line conditioning in the system. That said, if the line conditioning has adequate current capacity, we expect some benefit."

    That's a big "if," since some types of line conditioner can choke off current and squash dynamics. The same is true of active devices with inadequate capacity, and even a power supply's own internal regulation. "The current peaks drawn are much larger than the continuous amperage," Pass said, "so for power amplifiers you need a rating considerably higher than the nominal current use. If you don't have that, you might get some losses."

    Power According to Pass

    "The current peaks drawn are much larger than the continuous amperage," Pass said, "so for power amplifiers you need a rating considerably higher than the nominal current use. If you don't have that, you might get some losses."

    A 15 amp convenience outlet branch can have the same effect on a power amp. You don't want the AC mains voltage bouncing around in beat with the high dynamics of the music being played.

    .
     
  2. Ingenieur

    Ingenieur Forum Resident

    You have no control over the utility.
    THD is lowered to <3% but not eliminated
    Utilities are allowed 6% iirc
    S/N is also improved
     
  3. Ingenieur

    Ingenieur Forum Resident

    Per NEC
    20 A branch CB requires 12 AWG
    A 15 A CB can use 14
    Most use the 20's
    Receptacles are usually 15 A rated, you can get 20's

    as others have said
    Run a dedicated 20 A with 10 AWG.
    If you can afford add a conditioning xfmr
    And a few ground rods
     
    Rick58 likes this.
  4. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    The earth does not possess some magical mystical power that sucks nasties from an audio system.

    "Electromagnetic Compatibility Engineering"

    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 that 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
     
  5. Ingenieur

    Ingenieur Forum Resident

    no
    But it does negate the difference between N and G with are bonded at the service panel and the utility xfmr.

    easy check.
    Measure between G and N on a receptacle with equipment running. If close to 0, <2 or 3 volts, fine, if greater you may have an issue

    the lower the ground, the better the lightening and surge protection

    the NEC only requires less than 25 Ohm if measured, if not measured just drive 2 rods and call it good

    assume 25
    A conductor shorts to ground, metal stud, etc.
    If it has to return to the panel thru the ground rod only 120/25 ~ 5 A of fault current will flow and the CB will not trip

    in my industry we require <2 Ohm and checking every 6 months

    some noise can be shunted to G, hence tying shield to them, but it will get back to the source, better the G than Line or N
     
  6. Bananajack

    Bananajack Well-Known Member

    Location:
    Singapore
    Well well, this is a complicated thread ... cables (especially Power Cables) is a nearly religious issue.

    Own findings:

    Yes, you hear the difference. Add a 2000Dollar Power Cable to a 2000 Dollar set and it will be better.
    How much better. Err, in% or in $ or how shall I tell that to you? And how to tell how much better it
    is changing from a 50socks cord to a 2000socks cord? That is harder.

    And what exactly means ‘better’? Or issit just different ...

    The real question is the system value. Will be 4000$ be spent best 2000/2000 or maybe 3900/100 or
    what is the best relation? Decide for yourself ...

    Silver power cables sound better than copper power cables. Yes. Undoubtedly that gave the biggest effect.
    Sounds kinda weird though. Religious, I know ...

    I sold everything because:

    Vintage sets do not react so strong on power cords, new gear needs them. Quite true ... do they have used
    maybe better materials? I am talking about recapped high end vintage gear, not tired old sets.

    Old Tube amps seem not to need any special power cords, filtering or whatsoever. Is that because of the
    big transformers?

    Seemingly relatively inexpensive industrial cables do the job very well. Yes, I have changed to just making my
    own cables. Pocket friendly and very audible advantages. No need to pay for marketing blahs and the Maserati
    of the owner of that cable brand.

    There are 4 ways:

    A) Find out who makes the cable for your favorite brand. Yes, many purchase, they don’t do themselves.
    For instance the German company W&M makes cables for 4 or 5 (maybe more) brands, one of them
    being Van Den Hul. Also one or two US Brands bought there.

    Buy directly from factory.

    B) Have a look at Lapp Cables (German manufacturer), the oldest cable brand. These are top notch industrial
    cables. Several HiFi brands use their cable, mostly Lapp Oelflex. Excellent power cable. A skin filter, two
    connectors and a screwdriver... and you have saved 500 Dollar or so. Rega buys and sells these cables.

    Buy directly from the distributor. Yes, they sell also in small amounts/few meters.

    C) Oh, you want high end. Well, have a look at Lapp cables for industrial robots. THAT shielding is really good,
    otherwise there would be production problems. It’s a bit more fiddly due to many little cables inside, but
    really sounds good. Well liked in German forums ...

    D) Find a small small company that tries to get into the market ... and if their cables are really good, buy their
    overstocks (some sell on FleaBay). Cosmic Audio made me sell all my cutthroat price Kimber Cables. They
    were simply better (they don’t do Power Cords though)

    Little hint ... what’s good as a power cable is also good as a speaker cable. Not necessarily signal cable, that must
    be tested.
     
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  7. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA

    You are confusing the System Ground with the Equipment Ground.

    If a hot to grounded object ground fault event happens the path for the ground fault current to return to the source is not through the ground rod. The source is the electrical service entrance grounded neutral conductor, 'The Grounded Conductor'. The Grounded Conductor is bonded, connected, to the metal enclosure of the service equipment. All equipment grounding conductors connect to the grounded conductor. The earth shall not be considered a low impedance ground fault current path. All grounding electrodes of a building shall be bonded to the service equipment Grounded Conductor.

    Isolated ground rods are dangerous and actually can do more harm than good introducing noise on the chassis of equipment that is connected to it. Works great for hunting fish worms in the event of a hot to chassis fault though. Lightning loves isolated ground rods as well.

    .
     
  8. Ingenieur

    Ingenieur Forum Resident

    No, they are one and the same.
    The chassis is bonded to the service ground.
    If hot goes to frame or neutral it will use either the ECC or N as the fault path.
    But if the fault is to 'earth' it uses the ground electrode.
    Other wise frame goes to 120 until some creates a ground path.

    no
    If you have a ground fault, hot phase to hand, out feet, into earth, up rod into panel

    I did not say isolated, I said bonded to service electrode

    I design low Z grounding systems as part of my job, most are HRG also

    some facilities will have isolated grounds, a mine for example:
    -A station bed for surface equipment
    -A N bed separated by >50' and not bonded to the station grid, it is isolated until in the mine
     
    Last edited: Oct 6, 2020
  9. Archguy

    Archguy Forum Resident

    Location:
    Richmond VA
    Agreed: I like the stuff from Blue Jeans, or Zu Audio, or Morrow--all mid-priced at most; I'm convinced that the law of diminishing returns applies in this sub-field as well as in most. The first steps up from stock are usually the most noticeable. That said, if I had the money my friend the mutual-fund manager has, would I blow some on ridiculous stuff? Probably.
     
    head_unit likes this.
  10. bgiliberti

    bgiliberti Will You Be My Neighbor?

    Location:
    USA
    In my system, if power cords make a difference, I can't hear it.
    Speaker wire, and interconnect between pre-amp and power amp made a large difference. IC between CD player and pre-amp made a slight difference.
     
    Don Parkhurst and Ingenieur like this.
  11. Ingenieur

    Ingenieur Forum Resident

    The line level signal connects I can see making a difference. Low level, a few V, a few mA, plus a wide freq spectrum. The power cord, 120 V, several 1000 mA and 1 fundamental at 60 Hz, no signal or information.

    Again, this is a hobby, no right or wrong, no absolutes. I like German cars. I know people who will take off oem forged wheels and replace them with aftermarket ones costing 1000's. No performance benefit, measurable or subjective.
    Wrong? Dumb? Waste? NO!
    It's fun, helps the economy, brings enjoyment and a thoughtful project.
    Better than dope or drinking excessively.

    no harm, no foul.
     
    bgiliberti likes this.
  12. Gibsonian

    Gibsonian Forum Resident

    Location:
    Iowa, USA
    That's been my experience. I can make a difference with a line level cord change, the lower the signal the more I can impact it. I cannot hear these power cord changes, but think I could if I went to extremes, which I won't.

    With dope or drinking, I have been also been able to hear a difference!
     
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  13. bgiliberti

    bgiliberti Will You Be My Neighbor?

    Location:
    USA
    I also think it's a lot easier for the manufacturer to "voice" an IC, because it's in the signal path. I suspect that many of them intentionally tweak the high or lows, which is why the differences are so much more evident when we swap interconnects. The power cord differences, being out of the signal path, are likely to be much more subtle, and also likely to come into play under a narrower range if conditions -- i.e., large dynamics at high volume level. Since I rarely play above 82db at my listening position, I doubt that my SS power amp is ever "gasping" for line amperage/voltage. That could be why I can't hear any impact from PCs, while I very much can hear differences with ICs.
     
    Ingenieur likes this.
  14. Bananajack

    Bananajack Well-Known Member

    Location:
    Singapore
    You won’t believe it, but these aftermarket wheels with broader tires make a car worse, means higher fuel consumption, more power needed for the same speed, less good roadholding and compromised comfort.

    But it looks sometimes good ... they need to impress somebody or themselves.
     
  15. Tullman

    Tullman Senior Member

    Location:
    Boston MA
    There is certainly something to be said for cool looks, especially in the car world.
     
  16. Bananajack

    Bananajack Well-Known Member

    Location:
    Singapore
    Or to cover deficits ... always have the feeling when I see these big exhausts on a tiny Honda :p
     
  17. Tullman

    Tullman Senior Member

    Location:
    Boston MA
    Just trying to get more horse power.
     
  18. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    ECC?....... I assume you meant EGC. (Equipment Grounding Conductor)

    Not sure why you chose this example. "But if the fault is to 'earth' it uses the ground electrode."
    To what end? Electrical safety? Please explain.

    For this thread lets limit the voltage to 120V. Building structure? A house found in a typical housing development. Remember this thread is about power cords. We are way off base....

    If the fault is to mother earth there would be a closed circuit for the ground fault current to return to the source. A low impedance path? Hardly. It also adds stray voltage to the earth. Will it cause a regular T-M breaker to open? Now a GFCI breaker should trip due to the imbalance in the hot and neutral currents in the sensing unit. But not from a short circuit or overload condition.

    Source? Technically the source is the power company's utility power transformer.
    Ground fault current path could be the ground rod/s of the grounding electrode system for the electrical service of the house the hot circuit conductor is fed from.

    Note:
    (We have been using ground rods for the Grounding Electrode in our exchanges.) As you know there may two other electrodes found in a residential dwelling. Metal potable incoming water line and possibly a Concrete Encased Electrode, commonly called a ufer ground. Per the NEC they shall be all connected together and then be connected to the service entrance neutral grounded conductor. The connected together electrodes are considered one grounding electrode per the NEC. For this post I will continue using ground rods for the earth electrode.)

    Continue.

    Or, and,
    It could be the ground rod/s of the next door neighbor's electrical service.
    or, and,
    It could be the utility power transformer neutral conductor earth connection ground rod or plate electrode.

    What ever path/s, would it trip the OCPD, breaker? Soil resistivity would be at play. Simple Ohms Laws.
    The IEEE Emerald book recommends 5 ohms or less for a rod to earth resistance for commercial and industrial facilities. We know what the NEC says. Residential electrical contractors use the NEC and AHJ. What do you think the average rod to soil resistance for a house is? There are lots of variables to consider.

    Hot phase? I'm going to assume you mean a branch circuit hot conductor, the ungrounded conductor. Like the hot conductor found in a typical 15 or 20 amp branch circuit used to feed audio branch circuits.

    Hopefully the hot of the circuit for your example is GFCI protected and hopefully it will trip open when 6ma flows through the body in the closed ground fault circuit back the GFCI.

    If it's just a regular circuit breaker hot bared circuit wire and the person was holding the wire in his hand then he would be electrocuted.
    The only chance of survival would be as his body fell to earth the length of the hot wire is short enough the weight of his body falling to the earth would pull the hot wire from his tightly closed hand. If not his body would eventually be found. Circuit will still be energized.

    This might be a better example of why the NEC say's the earth shall not be used as a low impedance ground fault path. Definitely not for use as an EGC.

    Using the same bared hot wire. Turn off the circuit breaker. Push a metal stake or a long shaft screw driver in the earth soil. Connect the bared wire to the stake/screw driver. Turn on the breaker. Will the breaker trip open? Works great for hunting fish worms though. Good for killing pets too. How about a person walking in their bare feet through the grass with a wet early morning dew?

    Guys this is one of the dangers when using an isolated ground rod for an audio equipment ground. The NEC does allow an Auxiliary grounding electrode, driven ground rod, but it must be connected to the safety equipment grounding conductor of the branch circuit wiring. I would not recommend an Auxiliary Grounding Electrode though. It can actually add noise to the chassis of audio equipment that uses the EGC. It can also provide a path for lightning traveling through the earth in the event of a thunderstorm.

    You may have elsewhere said that in the thread. I was questioning what you said in this post.

    The SDS must be wired as a "grounded system".
    Per the NEC the SDS shall be bonded to the grounding electrode system of the main electrical service of the building.
    Yes you can drive as many ground rods as you want just as long as they are all tied together and connected to the main electrical service grounding electrode system with a minimum #6 cu wire.



    System Ground
    2017 NEC
    250.4 (A) (1)

    (A) Grounded Systems.

    (1) Electrical Systems Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.


    .
     
    Last edited: Oct 14, 2020
  19. Uglyversal

    Uglyversal Forum Resident

    Location:
    Sydney
    Can I join in?

    After many years of looking at them with disapproval - I do admit I always liked the way they look but thought "I can't throw money at that":biglaugh:.

    Well, a few days ago I've bought a snake oil power bottle, I had a bath in it, and I loved it!

    I went for the upper middle range, it had a metal shield, silver plated OFC conductors and gold plated contacts.
    I've connected it to the phono stage. I went back and forth with the old cable but there was no doubt, there was a noticeable improvement without having to strain myself to hear it. Mainly more bass and to a lesser extent clearer mids and highs, possibly a little more extension in the highs too.
    I don't know what it does to the power, or how it does it, perhaps the standard cables are just too crappy and as long as the manufacturer pays the fees required they get the stamp of approval but they shouldn't.

    Anyway, I don't care how, all I care is what it does, and if someone says I've been brainwashed I don't care either!

    In fact next week I am going to buy another.

    The only nuisance is the IEC plug is so big that it has to be squeezed near other connectors.
     
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  20. MGW

    MGW Less travelling, more listening

    Location:
    Scotland, UK
    Why on earth (boom, boom! o_O) would we do that?
    Most of the world is on 220 to 240V!
     
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  21. Brother_Rael

    Brother_Rael Forum Resident

    Location:
    Scottish Borders
    I recently added new power cables to my system. They replaced some others which I'd used for a few years. My system's pretty simple really, AVI active speakers, my CD player source and a passive preamp, new turntable added recently and a modest streamer, but the CD is my main media source. Soundwise, it's detailed and pretty revealing as that's the kind of sound I like.

    I'm lucky that I live in an area with good, stable electricity supplies. Never really had an issue with it and certainly nothing on the scale of some areas in the States I've heard of.

    The replacement cables didn't add or detract to the sound I'm familiar with from my system, so at least that was a good thing, if not quite the difference I may otherwise have expected to hear. I tend to be rather sceptical of some of the claims made by some, that old "night and day" kind of thing. Always strikes me there's a maybe more serious deficiency somewhere else that an accessory brings out than the abilities of the accessory itself.

    Either way, I decided to keep the new cables. There was maybe a touch more clarity, but so small I couldn't be sure. And even then, I put that down to capacitance or resistance diffetences between the cables than anything else.

    In the end, I sold the old cables - JPS Labs The Analog and a Russ Andrews Powerkord 100 - and kept the £10 RCP Technologies mains cables in their place.

    As a useful point of reference, I very much enjoy the contributions of Jim Lesurf from St. Andrews University in Fife, who also writes for Hi Fi News. His site is linked below:-

    http://www.audiomisc.co.uk/Electronics/audio/Analog.html
     
  22. Tullman

    Tullman Senior Member

    Location:
    Boston MA
    With all due respect and you seem like a good guy, but you’re post is BS. You compared two pieces of ****. Also you advocate the shell game method of building a system.
     
    Don Parkhurst likes this.
  23. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Edit to my above post.

    Add wording.

    If it's just a regular circuit breaker hot bared circuit wire and the person was holding the wire in his hand then there is a good chance he would be electrocuted.

    .
     
  24. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Good point.:righton:
     
  25. Ingenieur

    Ingenieur Forum Resident

    ECC?....... I assume you meant EGC. (Equipment Grounding Conductor)
    Yes EGC

    Not sure why you chose this example. "But if the fault is to 'earth' it uses the ground electrode."
    To what end? Electrical safety? Please explain.
    Because it is the only path, safety and to ensure tripping of the protective device

    For this thread lets limit the voltage to 120V. Building structure? A house found in a typical housing development. Remember this thread is about power cords. We are way off base....Yes you are, power cords are 120 VAC devices (in the US)

    If the fault is to mother earth there would be a closed circuit for the ground fault current to return to the source. A low impedance path? Hardly. It also adds stray voltage to the earth. Will it cause a regular T-M breaker to open? Now a GFCI breaker should trip due to the imbalance in the hot and neutral currents in the sensing unit. But not from a short circuit or overload condition. Obviously, but the fault current still returns to source thru the ground rod (or plumbing bond, etc.)

    Source? Technically the source is the power company's utility power transformer. Technically the source is the utility generato, but if a Wye-Delta connection isolated from Zero Sequence current
    Ground fault current path could be the ground rod/s of the grounding electrode system for the electrical service of the house the hot circuit conductor is fed from.
    There are always parallel paths, the equivalent Z being the path of least resustance

    Note:
    (We have been using ground rods for the Grounding Electrode in our exchanges.) As you know there may two other electrodes found in a residential dwelling. Metal potable incoming water line and possibly a Concrete Encased Electrode, commonly called a ufer ground. Per the NEC they shall be all connected together and then be connected to the service entrance neutral grounded conductor. The connected together electrodes are considered one grounding electrode per the NEC. For this post I will continue using ground rods for the earth electrode.) Obviously, and the structure it self if constructed of steel...I've never seen a concrete encased electrode on a single family dwelling

    Continue.

    Or, and,
    It could be the ground rod/s of the next door neighbor's electrical service.
    or, and,
    It could be the utility power transformer neutral conductor earth connection ground rod or plate electrode.
    Again, it will be all of them, parallel paths.
    Unless the next door neighbor is on a separate xmfr, then the Zero Sequence current sees infinite Z
    Could be the poles butt coil.


    What ever path/s, would it trip the OCPD, breaker? Soil resistivity would be at play. Simple Ohms Laws.
    The IEEE Emerald book recommends 5 ohms or less for a rod to earth resistance for commercial and industrial facilities. We know what the NEC says. Residential electrical contractors use the NEC and AHJ. What do you think the average rod to soil resistance for a house is? There are lots of variables to consider.
    You are stating the obvious.
    I design and install grounding systems as part of my job,
    I measure them on a regular basis.
    I am an IEEE member and have almost all industrial power related publications.
    We call it the Green Book: Green Book is the IEEE Standard 142, Recommended Practice for Grounding of Industrial and Commercial Power Systems


    Hot phase? I'm going to assume you mean a branch circuit hot conductor, the ungrounded conductor. Like the hot conductor found in a typical 15 or 20 amp branch circuit used to feed audio branch circuits. Semantics, you know what I mean, line, ungrounded conductor, etc. It is a phase, in this case single with an opposite at 180 degrees, the sum being 240 line-line

    Hopefully the hot of the circuit for your example is GFCI protected and hopefully it will trip open when 6ma flows through the body in the closed ground fault circuit back the GFCI. No comment

    If it's just a regular circuit breaker hot bared circuit wire and the person was holding the wire in his hand then he would be electrocuted.
    The only chance of survival would be as his body fell to earth the length of the hot wire is short enough the weight of his body falling to the earth would pull the hot wire from his tightly closed hand. If not his body would eventually be found. Circuit will still be energized. I investigate electrical accidents as part of my job. I also wrote a law requiring sensitive ground fault detection on industrial equipment to increase personal protection. Research Charles Dalziel, he invented/patented the GFCI technology. The fibrillation threshold is determined by the following: I (mA) = body weight/(sqrt(time))
    Assume 200 lbs, 1/2 sec trip time. The person could take 283 mA before he likely went into cardiac arrest (98% probability).
    A persons Z is ~ 1.000 Ohm hand-foot (it varies 750 to 1500 and upon wet, dry, contact area, etc., there is document that lists all scenarios).
    So if the impressed voltage was 120 the person would see ~ 120 mA (minus ground path which is << 1000). A GFCI trips in < 10 cucles and < 10 mA. Person would be fine. If no GFCI and current is sustained he would by in trouble in time = (200/120)^2 ~ 2.8 sec. Since let-go current is on the order of 30 mA he is in trouble.


    This might be a better example of why the NEC say's the earth shall not be used as a low impedance ground fault path. Definitely not for use as an EGC.
    Never said it was, only if ECG is broken (we monitor it and trip the CB if >4 Ohm) or not in the circuit, feet on a wet bathroom floor, faulty hair dryer.

    Using the same bared hot wire. Turn off the circuit breaker. Push a metal stake or a long shaft screw driver in the earth soil. Connect the bared wire to the stake/screw driver. Turn on the breaker. Will the breaker trip open? Works great for hunting fish worms though. Good for killing pets too. How about a person walking in their bare feet through the grass with a wet early morning dew?
    Depends on the set-up.. In our systems yes. For example on a 7200 VAC system we have a < 4 Ohm bed, a 25 A NGR (166 Ohm) , and a relay set at 12 A. So if a 4160 fault to earth occurred, yes, it would.
    In a home, 120 to ground, perhaps. if the ground loop is less than 120/20 Ohms, yes, otherwise not. The CB is inverse time, so the lower the fault Z (the higher the current) the faster. Step potential is a separate topic, it is a station ground bed design parameter, as is touch potential.
    If the rod is 10' from the fault you'll have a gradient of approximately 120/(sqrt(2) / 10 = 8 V/ft, if the persons gate is 2.5 feet 20 V over 1000 Ohm or 20 mA, they would start dancing, but likely be OK.


    Guys this is one of the dangers when using an isolated ground rod for an audio equipment ground. The NEC does allow an Auxiliary grounding electrode, driven ground rod, but it must be connected to the safety equipment grounding conductor of the branch circuit wiring. I would not recommend an Auxiliary Grounding Electrode though. It can actually add noise to the chassis of audio equipment that uses the EGC. It can also provide a path for lightning traveling through the earth in the event of a thunderstorm.
    I never proposed isolated, I said bonded to the existing with 4 AWG to lower the system Z. In ANY post.

    You may have elsewhere said that in the thread. I was questioning what you said in this post. Nope

    The SDS must be wired as a "grounded system".
    Per the NEC the SDS shall be bonded to the grounding electrode system of the main electrical service of the building.
    Yes you can drive as many ground rods as you want just as long as they are all tied together and connected to the main electrical service grounding electrode system with a minimum #6 cu wire.
    You can have ungrounded systems, we use them all the time,
    You are restating exactly what I proposed: add ground rods bonded to the existing system.


    System Ground
    2017 NEC
    250.4 (A) (1)
    (A) Grounded Systems.
    (1) Electrical Systems Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
    So?
     

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