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Thread: Can a load center have a breaker as large as its main?

  1. #76
    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by Cookie View Post
    Lee, you are arguing ...
    No, I am only asking a question: Where did the current go?

    A circuit's black wire was shorted to the panel, and that left that circuit showing no current available and I only felt a small tingle when I touched the panel. So, where was the remainder of that current going?

    If it had been a garden hose that had been pinched, the water would have been unable to flow at all ... but we are only dealing with a pinched conductor here, not a pinched conduit.

    I keep hearing stuff said about where the current is believed to *not* be going, but that is not my question. I am asking where that current *was* going since it did not appear in the shorted circuit or between me and the concrete floor (apart from just enough to produce a small tingle).

    Question number 2: I ordered a PK4MB2LA "Back-Fed Circuit Breaker Retaining Kit" for the main breaker in my workshop panel, but that retainer is not the correct one for my panel and I cannot find what I *do* need. The panel I have is a QO612L100S, and it seems the only screw hole it has available for retaining a main breaker is on the left side of that breaker. The instruction sheet that came with that panel listed a part number for the retainer kit, but I no longer have that instruction sheet. So, can anybody here either straighten me out if I am missing something there or else help me find the retainer I actually do need?
    Last edited by leejosepho; 10-15-2011 at 03:27 AM.

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    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by jadnashua View Post
    While DMMs are nice tools, they can give some hard to understand readings because they have such high input impedances...you can get some significant voltage readings in places you wouldn't expect them but have little ability to actually flow any current.
    I had something like that happen yesterday, I believe. I was cleaning some junk from the attic in order to clear the way for the electrician when he comes, and I saw a clipped-and-taped end of a piece of old Romex hanging out of a box with no cover and laying loose up there ... and I decided to remove it and cover the box. Looking more closely, however, I also noticed another piece of old Romex connected to that wire inside the box and then running out and going down into a wall where an old mechanical timer is mounted, and I decided to remove all of that wire since that timer is obviously no longer in use or needed. After removing the cover from the timer, I checked for voltage before getting near any connections, and I saw something like 36 volts across the terminals in the timer ... and that means there must have been a very small "leak" at that clipped-and-taped end of the piece of old Romex hanging out of a box and laying loose in the attic ...

    ... and since safety is always first for me, I clipped the unneeded wires at the box by using a pair of insulated dikes while standing on a fiberglass ladder on a wooden floor before touching the terminals on that timer with anything other than my meter.

    As an aside here: What was that timer about in the first place? It is a mechanical, 12-hour, wind-up timer with a mercury switch inside and its output circuit appears to have been clipped when a new furnace was installed many years ago, but it is definitely not a thermostat, just a switch. So, was there a day when furnaces were run with simple on-off timers?
    Last edited by leejosepho; 10-15-2011 at 03:24 AM.

  3. #78
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by leejosepho View Post
    No, I am only asking a question: Where did the current go?
    A circuit's black wire was shorted to the panel, and that left that circuit showing no current available and I only felt a small tingle when I touched the panel. So, where was the remainder of that current going?
    I do believe that you have no understanding of current flow at all but are trying to sell everyone including yourself that you do. How much if any training or schooling have you had in electrical theory? Is everything you know about electricity been learned by doing?

    When a switch is open (turned off) how much current is flowing? Would the amount of current flowing be any different if there were five 60 watt bulbs verses three 60 watt bulbs? Where is that available current for the five bulbs flowing?

    What type of meter do you have that will show how much current there is available to flow in a circuit? I have been doing this for over 40 years and have never seen a meter that would give the available current in a circuit.

    The only current that matters was flowing through you and there was no remainder.

    The four main components of current flow are voltage, resistance, wattage, and current. In your case the voltage was a known of 120. The resistance of the path is what controlled the amount of current that flowed. If we knew the total of the resistance we could accurately figure how much current that flowed through your body.

    This does not work like you seem to believe. A twenty amp breaker does not allow 20 amps to flow continuously through the circuit it only protects the circuit to 20 amps. The load (resistance) will mandate how much current that flows through the circuit sort of like you explained about the welder in the other thread.
    Using you thinking the 50 amp breaker for the welder that was only drawing 30 amps must be letting the other 20 amps leak out somewhere. Where is that current leaking out to?

    EDITED TO ADD;

    Lee

    The last couple of pages on this link will tell you all about the available current on a single phase circuit.
    It does a better job of explaining where all that available current in you circuit was going than I would ever be able to do. Once reading this please post just how much available current you had in your little panel.

    http://www.cooperindustries.com/cont...lculations.pdf
    Last edited by jwelectric; 10-15-2011 at 05:37 AM.

  4. #79
    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by jadnashua View Post
    The ground rod is primarily for protection during lightening strikes...don't count on it for an effective ground ...
    Quote Originally Posted by leejosepho View Post
    ... asking a question: Where did the current go?
    Quote Originally Posted by jwelectric View Post
    I do believe that you have no understanding of current flow at all ...
    Please stop talking about me. I am trying to learn something useful here!

    @jadnashua: While searching for an answer to my "Where did the current go?" question, I now see I have been making some wrong assumptions and/or drawing some wrong conclusions based on mere anecdotes ... and I now know for myself what everyone here has been saying is actually quite true:

    Ground rods do *not* offer protection from stray/shorted current.

    My brother will likely not believe that since the work he did at the campground I had mentioned actually did help put an end to campers being shocked at their sites, but that is a matter for another day. For today, and while being completely safe about how my test was conducted -- "Mythbusters" is a great show for learning about safety -- I just went out and did a test that has proved to me in a very real and physical manner that my ground rod is definitely *not* a "neutral" and/or "ground" connection sufficient even for lighting a 60W bulb. With 120V available to it through my panel's ground wire, the bulb displayed a very light glow "to ground" ... and that glow was so low that I almost missed it altogether. So while that means at least a little bit of current was going "to ground" via the ground rod, I now know the level of "tickle" I had received a few days ago was not at all significantly affected/effected by that ground rod. So yes, and to all: I have been wrong here!

    New question: While that one circuit was shorted to ground a few days ago, why did some current flow "to ground" through me and no current at all flow through my meter between that incoming leg and the panel's neutral bar? And remember, the panel was not bonded at that time. I can now understand why I felt so little current going "to ground" since it really had no place to go, but I cannot understand (or actually, I just do not know) why no current could flow even through my meter and on back to the panel's neutral bar.

    @jwelectric: I am an Aspie who hardly ever learns anything by reading academic material. I need to either see something for myself or be shown or have it clearly explained.
    Last edited by leejosepho; 10-15-2011 at 06:40 AM.

  5. #80
    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by jwelectric View Post
    ... Using you thinking the 50 amp breaker for the welder that was only drawing 30 amps must be letting the other 20 amps leak out somewhere.
    Not true. That breaker would only see 50A as its maximum, and it would not care at all whether that amount of current ever went anywhere.

    Your self-choking ego and its continual desire to compare yourself to others and then find yourself greater is sickening, at least to me. But of course, I also am human and have some of my own issues in the security department.
    Last edited by leejosepho; 10-15-2011 at 06:57 AM.

  6. #81
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by leejosepho View Post
    Please stop talking about me. I am trying to learn something useful here!
    Then open your mind to things that are different than you believe them to be.
    Quote Originally Posted by leejosepho View Post
    My brother will likely not believe that since the work he did at the campground I had mentioned actually did help put an end to campers being shocked at their sites, but that is a matter for another day.
    The only thing that your brother did at that campsite was open himself up to some major law suites should someone end up getting hurt by his not knowing what he was doing.
    Quote Originally Posted by leejosepho View Post
    The point here, however, is that bonding the camping sites' panels to ground to send stray current there is how he rightly or wrongly shunted the shocking current.
    As has been pointed out many times the current is not shunted to earth and this is nothing more than flawed thinking. He did nothing to make the campsite safer by bonding everything to a ground rod and not even one electron was sent to earth. Every one of those electrons made it back to the transformer.
    Quote Originally Posted by leejosepho View Post
    New question: While that one circuit was shorted to ground a few days ago, why did some current flow "to ground" through me and no current at all flow through my meter between that incoming leg and the panel's neutral bar? And remember, the panel was not bonded at that time. I can now understand why I felt so little current going "to ground" since it really had no place to go, but I cannot understand (or actually, I just do not know) why no current could flow even through my meter and on back to the panel's neutral bar.
    As has been pointed out numerous times throughout this thread “there must be a complete path from the source back to the source for current to flow.” With no bonding jumper there is no complete path between the equipment grounding conductor and the neutral therefore no current reading could be made between the equipment grounding conductor and the neutral in the panel. If the bonding screw had been installed you still would not have been able to get a current reading as the breaker would not have held in long enough for a reading to have been made.
    Last edited by jwelectric; 10-15-2011 at 09:21 AM.

  7. #82
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by leejosepho View Post
    Your self-choking ego and its continual desire to compare yourself to others and then find yourself greater is sickening, at least to me. But of course, I also am human and have some of my own issues in the security department.
    I promise you that I have no ego problems. I know that I still after 40 plus years in the trade I have a lot to learn as this trade is an ongoing learning experience. If I seem to know more about this than you do them it might be because I do but instead of it making you sick it should make you eager to listen and soak up some of this knowledge that I offer to you for free.

    If you wish I will reframe from posting anything to questions you have and let you go through life as misguided as you are now unless someone else starts to make you sick with their knowledge.

    What say you? Do you want me to stop or not?

  8. #83
    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by drick View Post
    Your ground rods are for lightning protection. They will not accept power that has been generated by your power company and magically suck it into the ground. The earth is a lousy conductor of electricity.

    Arc faults are conceptually fairly simple devices. They monitor the power going out on the hot wire and returning on the neutral wire. This is why you must connect both wires to the arc fault breaker. The amount of power on each wire should be the same. When it is not the arc fault trips.

    Now you said you had a pinched neutral wire in a light fixture. This will cause an arc fault to trip because some of the power can now take a detour around the arc fault via the accidental neutral wire to ground wire connection created by the pinched wire. BUT you did not have the bonding screw installed!! SO the power could not make it back to the service conductor neutral. Your ground wires were essentially a dead end road going nowhere and doing nothing. When you installed the bonding screw you connected all the ground wires to the service conductor neutral and suddenly power on the ground wires had a place to go! Now when you turned on the light the arc fault detected that not all the power was returning on the neutral and tripped!
    It has taken me a couple of days to get back to your post here, but I want you to know I had not forgotten about it. I have not tried the AFI breaker since correcting that second short, but yes, what you have said would definitely explain things ... and I thank you.

    Quote Originally Posted by drick View Post
    Well I suppose you are still wondering why you have grounded outlets in the house and are thinking that they must have something to do with the ground rods. Well they don't. The ground wiring protects you from electric shock by (hopefully) tripping the circuit breaker. As an example, if the hot wire in your shop light suddenly broke off inside the fixture and came in contact with the grounded metal frame of the fixture it would cause a dead short. All the power leaving the breaker on hot wire would immediately return on the ground wire which is of course connected to the service conductor neutral via the bonding screw. The current would likely be in excess of 1000 amps. Your 15 or 20 amp breaker will trip and you will not be electrocuted by the damaged fixture. If you remove the bonding screw from your panel the breaker will not trip!! Your ground rods will not magically suck up enough power to trip your circuit breaker. Now if you touch the fixture you will be electrocuted!
    Yes, and exactly that is what had once happened to me. I was working in a place where the boss had a metal box on the end of a piece of rubber cord, a big no-no, and he was using a metal goose-neck lamp plugged into that box. Maybe a wire had come loose inside the box or maybe the light's plug needed to be put in the other way (back then in the day of same-sized blades), but I had picked up the box with one hand and the light with the other, and WHAM! Instantly. Both had been on the floor, and now there I was with current holding me in a frozen position and with a loud buzz sounding in my brain while I was trying to holler "Unplug me!" I have no idea whether any of my words actually came out, but the boss at least saw something was wrong and pulled the cord from the wall socket.

    Still in relation to the matter of a receptacle's ground, there is yet another purpose beyond lightening and what you have mentioned, at least in one case known to me:

    I once had a computer that would not work correctly unless it was connected to a grounded receptacle, and that used to be a big problem for me in any room that did not have grounded outlets. Using a 3-to-2 adapter could get the device plugged in and powered up, but it still needed a ground in place to actually work. So, and while I would no longer do this today, there have been times in the past where I have temporarily added a jumper wire from an outlet's neutral screw to its ground screw in order to make it possible for that particular machine to work.

  9. #84
    DIY scratch-pad engineer leejosepho's Avatar
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    Quote Originally Posted by jwelectric View Post
    ... open your mind to things that are different than you believe them to be.
    My mind is not closed, and I am continually checking my mere beliefs against actual facts. So again: Please stop talking about me and just stick to the relevant facts!

    Quote Originally Posted by jwelectric View Post
    The only thing that your brother did at that campsite was open himself up to some major law suites ...
    You are full of ****. By the time he was done, people were no longer getting shocked ... and that fact is true even if he never understands or believes how that actually happened.

    Quote Originally Posted by jwelectric View Post
    ... current is not shunted to earth ...
    I now know that ...

    Quote Originally Posted by jwelectric View Post
    ... and [believing current is shunted to ground] is nothing more than flawed thinking.
    You are wrong. Simple ignorance is one thing, but "flawed thinking" is a judgmental statement having nothing to do with the physical facts at hand.

    Quote Originally Posted by jwelectric View Post
    ... “there must be a complete path from the source back to the source for current to flow.” With no bonding jumper there is no complete path between the equipment grounding conductor and the neutral therefore no current reading could be made between the equipment grounding conductor and the neutral in the panel.
    You have missed my question. While the panel was not bonded and the hot was shorted, no current appeared between hot and neutral even though the neutral's return path was good and no significant amount of current was being shunted to ground.

    Question: Do you have any idea where I can get the breaker retainer you had informed me about being needed in my panel?
    Last edited by jwelectric; 10-16-2011 at 07:36 AM. Reason: To remove ugly word

  10. #85
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by leejosepho View Post
    Quote Originally Posted by jwelectric View Post
    Then open your mind to things that are different than you believe them to be.
    My mind is not closed, and I am continually checking my mere beliefs against actual facts. So again: Please stop talking about me and just stick to the relevant facts!
    Yes you have a fixation that connecting to a ground rod seems to cure everything. This is evidenced in your next statement.
    Quote Originally Posted by leejosepho View Post
    Quote Originally Posted by jwelectric View Post
    The only thing that your brother did at that campsite was open himself up to some major law suites should someone end up getting hurt by his not knowing what he was doing.
    You are full of ****. By the time he was done, people were no longer getting shocked ... and that fact is true even if he never understands or believes how that actually happened.
    So you and him both are convinced that by losing a staple in a cable that is arcing to the bark of a tree fixed the damaged sheathing of the cable? Or was it the connection of the metal boxes to the ground rod that fixed this damaged sheathing of the cable? Come on now Lee we all know that he did nothing to improve the cables. As to no one being shocked proves nothing. Remember the thread where the equipment grounding conductor was lifted and the devices connected to a rod at a pier in order to stop the tingle shock when touching the metal pier. Instead of taking away the shock they removed the safety line that would save a life and did nothing to make the situation safer.
    Quote Originally Posted by leejosepho View Post
    Quote Originally Posted by jwelectric View Post
    current is not shunted to earth
    I now know that ...
    Then how did what your brother did solve the problem and everyone quit getting shocked? What about you comment here about the short in the panel and nothing being shunted to the ground rod.
    Quote Originally Posted by leejosepho View Post
    You are wrong. Simple ignorance is one thing, but "flawed thinking" is a judgmental statement having nothing to do with the physical facts at hand.
    Call it a judgmental or flawed, either way it is incorrect just as your statement below about “no significant amount of current was being shunted to ground”
    Quote Originally Posted by leejosepho View Post
    You have missed my question. While the panel was not bonded and the hot was shorted, no current appeared between hot and neutral even though the neutral's return path was good and no significant amount of current was being shunted to ground.
    In order for current to flow there has to be a complete path for current to flow. In order to have current between the hot and neutral conductor and the breaker not open there must be a load of some sort between the two.
    If you are saying there was not voltage present between the two then I am going to guess that there was something open between the test points.

    Quote Originally Posted by leejosepho View Post
    Question: Do you have any idea where I can get the breaker retainer you had informed me about being needed in my panel?
    From the manufacturer of the panel if that panel is designed to accept one. It may be that the panel has been discontinued and will need to be replaced with a newer model in order to tie the breaker down.

  11. #86
    DIY Senior Member BobL43's Avatar
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    Quote Originally Posted by jwelectric View Post
    Yes you have a fixation that connecting to a ground rod seems to cure everything. This is evidenced in your next statement.
    So you and him both are convinced that by losing a staple in a cable that is arcing to the bark of a tree fixed the damaged sheathing of the cable? Or was it the connection of the metal boxes to the ground rod that fixed this damaged sheathing of the cable? Come on now Lee we all know that he did nothing to improve the cables. As to no one being shocked proves nothing. Remember the thread where the equipment grounding conductor was lifted and the devices connected to a rod at a pier in order to stop the tingle shock when touching the metal pier. Instead of taking away the shock they removed the safety line that would save a life and did nothing to make the situation safer.
    Then how did what your brother did solve the problem and everyone quit getting shocked? What about you comment here about the short in the panel and nothing being shunted to the ground rod.
    Call it a judgmental or flawed, either way it is incorrect just as your statement below about “no significant amount of current was being shunted to ground”
    In order for current to flow there has to be a complete path for current to flow. In order to have current between the hot and neutral conductor and the breaker not open there must be a load of some sort between the two.
    If you are saying there was not voltage present between the two then I am going to guess that there was something open between the test points.

    From the manufacturer of the panel if that panel is designed to accept one. It may be that the panel has been discontinued and will need to be replaced with a newer model in order to tie the breaker down.
    Oy, oy oy, oy, oy.
    I am definitely not a pro plumber, but I am a pro crastinator

  12. #87
    DIYer, not in the trades LLigetfa's Avatar
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    JW, you seem to hold steadfast to the theory that not a single electron of current flows through the ground which you must know to be wrong. The ground (earth) can and does somtimes provide a current path.

    In electrical safety training we were taught that current, not voltage is the killer. In the event of a fallen high voltage line, we were taught to bunny hop and not to run away from the danger. When one runs, there can be a voltage differential between one foot and the other and current can flow through the ground between one foot and the other.

    In the example of the dock, the tingles felt were from current flowing through the body to the water (earth ground).

  13. #88
    Electrical Contractor/Instructor jwelectric's Avatar
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    Current can and does flow through earth but a connection to a ground rod does not mitigate the danger of current flow through the body as being discussed in this thread. The current flowing through earth is seeking its source.

    The connection to the grounding electrode system does not lessen the danger of electrical shock to someone coming in contact with something energized. As a matter of fact the tingle that Lee felt was due to current flowing through earth or at least the concrete floor he was standing on.

    Every electron that is flowing through earth is searching for its source where it must return. This law that states that the current must return to its source is evidenced by the primary and secondary connection of the transformer at the pole. The neutral of both the primary and secondary connects to the grounding electrode at the pole which holds the transformer.
    If the laws of current flow were as some think then why doesn’t the current of the primary come in on the neutral of the secondary that is connect to the same point? The answer is simple; every electron is seeking its own source.

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    General Engineering Contractor ballvalve's Avatar
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    As to Lee' rather un-nice comments on JW's personality [on line, at least] I must say he reminds me of Sister Jerome from the 7th grade, who carried a pointer that must have been hickory, since it never broke on the massive strokes adminstered to me.

    But now I remember her fondly as one of the best teachers I ever had. She had eyes in the back of her head and a snicker behind her would get a direct hit in nano second turn around. Plus she was big as a football player, and her boots scared the hell out of us. No electric schocks for her!

    Hit a kid now with a wooden spoon and its off to jail and the special child abuse prosecutor paid by production of convictions.

    I left my kid in the tool van with a German Shepherd that would go through the closed window if someone even looked at my kid, while entering a store for a few minutes. My wife told me I would have gone to jail for that. Amazing.
    Last edited by ballvalve; 10-16-2011 at 01:54 PM.

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    DIYer, not in the trades LLigetfa's Avatar
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    Quote Originally Posted by ballvalve View Post
    My wife told me I would have gone to jail for that. Amazing.
    Yes, but because of the dog. I think there are more laws regarding the treatment of dogs than children.

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