This article was posted 03/20/2007 and is most likely outdated.

Myth No. 1 – Grounding and Ideal
 

 
Topic - Grounding and Bonding
Subject
- Myth No. 1 – Grounding and Ideal

March 20, 2007  

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Myth No. 1 – Grounding and Ideal

 

This is the first installment of a new series we’re developing to uncover industry myths.

 

Pathway to ground: Pathway to Improve Safety and Power Quality

 

Image IDEAL Industries, T&M Division

http://www.idealindustries.com/pdf/tm/Pathway%20to%20ground.pdf

 

Mike Holt’s Comment: The following text by Ideal is typical in what we see written on the topic of Grounding in our industry with lots of false statements.

 

Ideal: When the topic of power grounds comes up, the focus tends to be on the earth ground system itself, whether a single ground rod, mat, or grid system. While a low effective resistance is very important, the ground conductor and the terminations on that conductor will often be overlooked. A fault current has to pass through every connection on a ground conductor before it can reach the earth to be safely carried away.

Mike Holt: Fault current is not trying to reach the earth, it’s trying to get to the source.

 

Ideal: Testing of the effective resistance of a ground is important, but a good testing program must include the ground conductors and it’s connections and splices. The electrical ground system ultimately includes the grounded device itself, and the entire pathway back to the earth ground.

 

Ideal: The impedance of the ground conductor can be seen as the pathway that a faulted current will have to take to reach the earth ground system.

Mike Holt: Fault current is not trying to get to the earth, it’s trying to get to the source.

 

Ideal: When insulation fails, a short circuit occurs. Protective devices like fuses or breakers open to stop the fault current, but before these devices can act, the ground conductor must carry the fault enough to become a lower pathway to ground could suffer the consequence.

Mike Holt: This makes no sense.

 

Ideal: This high resistance bond can be a source of power quality problems as well.

Mike Holt: Is it ground or bond?

 

Ideal: Modern digital electronics work at 5-volt levels or less, switching, communicating and controlling our automated industrial processes. Imagine the problems fault currents cause when they produce voltage on the ground side of solid-state circuits. This common problem can be resolved completely by providing low resistance pathways for fault current to follow to earth ground.

Mike Holt: Grounding (a connection to the earth) does not reduce voltage on metal parts from a ground fault.

 

Ideal: Another related power quality issue is stray voltage. Very commonly caused by connecting the ground and neutral conductor in a sub-panel, stray voltage can energize all exposed metal and building steel. Stray voltage in dairy farms causes cows to eventually stop giving milk, and in hospitals will cause many problems with high tech diagnostic equipment, and patient connected equipment.

Mike Holt: I’m not sure what this has to do with the article on Grounding, because grounding does not reduce Stray Voltage.

 

Ideal: In our modern electrical environment, non-linear loads cause high neutral currents. The neutral conductor can carry substantial current back to the earth ground system.

Mike Holt: The grounding conductor (conductor to the earth) plays no role in nonlinear loads, and neutral current is not trying to get to the earth.

 

Ideal: The ground conductor is not considered an electrical conductor, and is present to provide a low resistance pathway for fault current.

Mike Holt: Grounding to the earth is not intended to provide a low resistive path for fault current.

 

Ideal: The neutral must be carried back to the service entrance, and can only be bonded to the ground conductor at the main neutral buss, where a large copper conductor carries all the return and faulted current back to the earth.

Mike Holt: Ground fault current is not attempting to return to the earth.

 

Ideal: Sometimes through error or ignorance, the neutral and ground are connected upstream from the service entrance. This is called a false, or bootleg ground. If the neutral and ground are connected anywhere else in the building, all grounded metal becomes part of the neutral conductor, constantly energized and creating various voltage potentials on electronic equipment. This causes many nuisance problems with automated equipment and computers, but can also create a hazardous and expensive electrical environment.

Mike Holt: I don’t understand the comment about expensive electrical environment.

 

Ideal: The solution to these problems is to include complete ground pathway testing as part of the standard procedure in your facility, and to choose test equipment which will help you locate and identify high resistance ground paths, and locate and eliminate bootleg grounds.

 

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Comments
  • I suppose different parts of the country have soil that conducts better than around here. But, I promise you, you can connect a 20 amp breaker to a ground, in this area and the current will NEVER return to the transformer or trip the breaker. You can drive ground rods until your worn out and the result will be the same. You Have to be bonded to the neutral.

    Fred
    Reply to this comment

  • Mike, I am anxious to see 250 in the 2008 code book. 2005 isn't all that bad if you read it all. But a few changes and clarifications(especially FPN) would be helpful. Don't reckon we'll live long enough to see the text books all corrected

    Fred Madden
    Reply to this comment

  • "Basically you hit the nail on the head... Are we discussing high-voltage systems? Premises wiring? Is it a grounded system, ungrounded, or resistive grounding system? Are we discussing surge protection or lightning protection?"

    We are discussing about equipment grounding and bonding regardless of system grounding and level of voltage.

    The vector diagram of different system grounding will show the explanation of what will be the voltage reference to ground during a single-line-to-ground fault. Similarly if single line to ground happened inside an enclosure, it can be compared with an ungrounded system. If energized enlosure in an ungrouded system will not to be grounded/bonded in a single line to ground fault the potential difference measuring from the energized enclosure to ground will be equal to line-to-line divided by square root of 3 because of the system capacitance. If the energized metal enclosure is grounded and bonded (during single line to ground fault) if you measure potential difference from metal enclosure to ground the votage is zero. Using this exaample it will mean that grounding reduces the energized metal part to zero. Bonding will not wait for the second ground fault to protect person because grounding in single line to ground will reduce the voltage to zero or minium voltage with proper grounding. This can be proven experimentally or through the vector representation.

    In a solidly grounded system, it is true that the bonding will be the return path to open the overcurrent protection. This is one use of bonding. However, another use of grounding as proven by the vector representation of solidly grounded system, will be to reduce the energized enclousre to zero for safety. It will not wait for the circuit protection to trip first before bringing the voltage to zero. Othewise it will be unsafe at the instant of ground fault and somebody is touching the enclosure. It is difficult to explain because vector diagram can not be posted in this reply. Electrical engineer expert in system grounding can explain this. Vector representation based on engineering principles would show that if a current carrying wire is grounded it will have a zero voltage to ground is zero. As in the ungrounded system or corner-grounded delta system.

    If grounding will not reduce line voltage to zero if it touches the ground then you are correct. But the truth is once one of the line touches the ground it can be proven that voltage will become zero from this line that touches the ground and zero.

    Therefore we can conclude that this will be the same in an equipment grounding.

    Bobby Ocampo
    Reply to this comment

  • From all the replies I've seen, I believe it only goes to serve what Mike Holt was trying to, at least in part, get across to everyone. There is and continues to be misconceptions in regards to grounding, bonding and the grounded conductor. I would never try to speak for Mike or anyone else for that matter and if I'm incorrect, I'm sure Mike will let me know. One of the most humblest things a person can do is to admit that they had the wrong understanding and be willing to open their minds and accept the correct way of doing things. Mike's website provides a very concise explanation and correct application of bonding and grounding. It's in harmony with the NEC and, with intent to offend no one, sound reasoning. The misapplication and understanding of this subject has gone on for years. Hopefully with the help and service that Mike's website offers, we will all be able to come together and start a new generation out with the proper understanding of this subject.

    Ben Mickler
    Reply to this comment

  • Mike Holt is wrong , stray voltage do cause problem magnetic forces from romex laying across water pipe dose induce voltages into the grounding metal pipe and these voltages can cause electrical shock to people taking shower if not proper grounding to earth is not maintain. I have deal with these stray voltage in the pass and fix them by properly groundig the water pipe to earth .These stray voltages could get into computer circuit and cause data errors.

    John Hall
    Reply to this comment

  • "Grounding" (earthing) is nice to have - Good BONDING is an absolute necessity!!

    R. B. Melton, Jr
    Reply to this comment

  • Mike - This reinforces what I learned many years ago as a new apprentice. Slang words for tools and equipment that were not understood by vendors or electricians from another area. Confusion results. Equipment manufacturers try to add something to their sales pitch over what their competitors say so you will purchase what they have to sell. If the product is basically the same they use different wording in the description. Confusion results. I attended a training class many years ago about training people to do new jobs. It is amazing what you may think is clear instruction can be misunderstood by someone unfamiliar to the new, to them, task. If the job they do is botched up it really makes you wonder who was at fault....it could be your instructions. As a result of what I learned, I have always attempted to be as clear and precise as possible, and taught others the necessity of being so. Forget the slang when talking or explaining, no abbreviations when writing.

    Rod Johnson
    Reply to this comment

  • Thanks Mike and keep it up. Myself, am tired of driving rods into the ground and attaching a minimum # 6 copper conductor so that the structure does not float up into the air.

    Mike
    Reply to this comment

  • Mike, Does your grounding book still hold true or do you need to update it? Cash in Mike and make a revised edition and sell it at a reasonable price to "spread the word". You should make a quick reference for "DUMMIES" or a fundemental section on all of the related ground(ing) bond(ing) Neutral(s) and other related topics of misconception on this subject, with your patented charts, graphs and illistrations Then a bit more in depth half of the book for us people with enough knowledge to be dangerous and to confuse ourselves. EVERYONE could use a EASY reference grounding guide. EVERYONE. Like I said some people may just confuss themselves, I have seen it, done it myself and seen speakers do it.

    Also most people speaking on the subjects are speaking like politicians and with confidence so people don't argue they just change there train of thought on the issues. Presentation is big.

    Cherry
    Reply to this comment

  • The marketing industry can get anything wrong and it should not reflect on the parent company. Tyco did a national, if not international campagin, on "Do it once, do it right." And they got the art wrong. They showed a wire going under a screw with the wire opening facing the wrong way. I now use in when I teach classes.

    Rex Cauldwell
    Reply to this comment

  • Mike, I am not impressed with this article, I see it as a sort of "face off" between yourself and leading industries. I think it, a little indignified of yourself to present your case in such a format. I have always enjoyed your news letters and such, however this article....man I thought you were better than this. The infamous "MIKE HOLT" takes on IDEAL Industries, there is your headline, now lets move on.

    Steven Dobbins
    Reply to this comment

  • While Ideal is not entirely correct in their wording, I believe they are not aiming at industry people with their comments. If one wishes to riled up about this, why not aim at the NEC and thier own confusion with the terms bonding/grounding.

    Steve
    Reply to this comment

  • I didnt see a problem with any of Ideals statements and anyone who would like to discuss them point by point Im all ears. No quick 1 sentence answers with no supporting theory to back it up.

    sherman
    Reply to this comment

  • Mike, as a young man (many years ago) I remember wiring the old two wire receptacles. The neutral was refered to as the "ground wire" by many good or at least productive electricians. Linemen often called the neutral the ground. I've heard guys say " I can't believe that ground wire shocked me" I think this confusion in terms has carried on down through the years and still causes problems.

    Fred Madden
    Reply to this comment

  • This all comes back to misusing the term ground for the return line, which may or may not be electrically connected, well or poorly, to the ground beneath our feet. Rather than fix the vocabulary, we re-write the dictionary to accomodate our bad usage.

    I think this is how the Supreme Court cooks up some of its creative rulings.

    Matt
    Reply to this comment

  • Mike, You 100% correct; and ALL manufacturers (and some contractors and inspectors) are guilty of perpetuating many different myths. Just remember, catalogs and advertising come from a Marketing Department with limited to no knowledge. These people are also writing for the general public, and are prone to exageration and mis-statements by the nature of their work. It's too bad that someone with some knowledge doesn't catch and correct these errors. I can't wait to see what myth you bust next (I've got plenty of ideas.)

    Gary
    Reply to this comment

  • This grounding myth is out there big time. A few weeks ago when I was in Home Depot, I looked in the following wiring books: Better Homes and Gardening, Black and Decker, Stanley, and the Home Depot book and there was one other which name I cannot remember. These books were either directly stating or simply implying that the ground fault current was just going into the earth or using the earth as the proper fault current return path. Siemens had this myth for many years on their free “quickSTEP” online training courses. Thanks to Mike Holt that was fixed. Siemens still has the myth on their older version called the “STEP 2000” training program which can be downloaded from their website. I suspect that the biggest culprit in spreading this myth is the group of people who produced the two fine print notes (which stand alone at the beginning of Article 250) in four consecutive editions of the National Electrical Code. These are the 1981, 1984, 1987, and the 1990 editions. That's twelve straight years of hazard causing information produced by the people who are supposed to be doing just the opposite. I have been told that they are getting better though. I hope so.

    Ralph Greene
    Reply to this comment

  • I believe that much of the confusion about grounding has to do with a lack of a clear yet comprehensive presentation of the subject. I have yet to find a text that covers grounding adequately.

    Jan Harris P.E.
    Reply to this comment

  • Mike, those of us trained in electron flow 'know' current is never trying to reach ground, but always trying to reach the source. Engineers whose training only touch on electricity as a requirement, and all those trained formally as 'electrical engineers' seem to have their curriculum based on semiconductor theory. Those fundamentals started them on 'hole flow' and they carry it forward into every disciplin. So, from their perspective, current IS trying to get to ground to complete the path. I'm taking an excerpt from your comments to send to my English teacher son-in-law. Hopefully he'll post it and use it to convice his students to really learn and study the language so they can express themselves and be understood in writing. Thanks for the comments. Good article.

    Z

    John 'Z-man' Zoll
    Reply to this comment

  • If this article is any indication of what is to come, it does not look like a series of myth-busting comments. Instead, it looks like a diatribe against a manufacturer's incorrect usage of terminology. Might I suggest a personal correspondence with such manufacturers to educate them rather than post such rubbish?

    Richard Kurzawa, P.E.
    Reply to this comment

  • I currently work for a distributor of low voltage equipment for fire and security equipment etc. We have access to documentation of products from over 400 vendors if I remember correctly. Nearly every piece of documentation I see that is a “cut sheet” or sales flyer is either missing pertinent information or has errors in the information. Generally the “installation sheet” is more accurate, but not always.

    In my opinion, the marketing people don’t know enough about the product to describe it properly or catch their own mistakes. I think some of the technical people either don’t have time to look over the marketing people’s work, or don’t read English well enough to proof read the work.

    Dale H
    Reply to this comment


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