(206) 949-5683, Top Rated Plumber, Seattle
Page 3 of 7 FirstFirst 1234567 LastLast
Results 31 to 45 of 92

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

  1. #31

    Default

    No, Lee, something, somewhere is really really wrong. I don't mean to be rude either, but, honestly, Lee, it is time to just wait for an electrician. Ballvalve's description of that picture is right this time, Lee. He is right Lee. Time to stop working on it, Lee. I would. So far, you have been lucky Lee. It is time to put away all the tools, call an electrician if you haven't, make an appointment and get him out there as soon as possible. Something is not right Lee. You might get hurt. Put away the tools, go inside and call one, make a cup of coffee and call it good for right now. And, let us all know later, what he did and how it is going. okay?
    Last edited by Cookie; 10-10-2011 at 11:51 AM.

  2. #32
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    It is not the bulb that is tripping the AFCI device but something else. It might pay you to redo some of the things you have done with the installation of the circuits as it sounds like there might be some major issues.

    Cookie offers some sound advice. Be sure that it isn’t one of those good old boys that can save you a hand full of dollars as most of them have no more knowledge than you.

  3. #33
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    Quote Originally Posted by jwelectric View Post
    It is not the bulb that is tripping the AFCI device but something else.
    Prior to my bonding the panel, the AFI breaker worked fine all the way around. All the light bulbs lit and I could run my drill press, bench grinder or whatever else without tripping the breaker. After I had bonded the panel, the small AC adapter providing power for the speakers for my iPod was all the AFI breaker would/could power before tripping.

    Quote Originally Posted by jwelectric View Post
    It might pay you to redo some of the things you have done with the installation of the circuits as it sounds like there might be some major issues.
    With the panel's main breaker off, I have no continuity between any black and the panel's neutral bar or any black and the panel's ground bar. Every box anywhere is grounded, and all connections in any box are twisted and nutted, including ground wires. I remember people complaining about AFI breakers being troublesome a few years ago, and these two I have are older ones from the used panel the electrician is going to install at our house ... and that leaves me far more suspicious of them than of there being trouble in my workshop. In any case ...

    Prior to bonding the panel, I did have continuity between the panel's neutral bar and ground, and that did not seem right to me. So I will go out there this morning and try to figure that out. I will turn off the feed breaker at the house and disconnect all white and ground wires in the workshop panel and check for continuity anywhere and report back. Overall, however, the simple question here is this:

    What could make an AFI breaker trip when a 60W load is applied after the panel has been bonded?

    Quote Originally Posted by jwelectric View Post
    Cookie offers some sound advice. Be sure that it isn’t one of those good old boys that can save you a hand full of dollars as most of them have no more knowledge than you.
    Cookie means well, but we are now way past the matter of safety while working on anything. We are now dealing with a problem that seems to have everyone baffled and we will see who might finally get it figured out! Also, the electrician who has me on his project list is definitely not "one of those good old boys" who cannot be trusted to do things properly ... and at the same time, neither is he one of the arrogant and/or self-righteous types who judge their customers by their own knowledge (or lack of it) and/or the sizes of their wallets.
    Last edited by leejosepho; 10-11-2011 at 07:01 AM.

  4. #34

    Default

    I don't know what to say.
    I hope you get it fixed.
    Last edited by Cookie; 10-11-2011 at 08:20 AM.

  5. #35
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    Quote Originally Posted by Cookie View Post
    I don't know what to say.
    I hope you get it fixed.
    I thank you, and I have ... and now for a friendly, tongue-in-cheek moment ...

    Whew, Cookie, I never could have imagined you had the connections to have the power turned off to the entire city here while I was out looking for that problem this morning! However, and just a few minutes after I had posted, a three-hour blackout began ...

    How did you do that?!

    **end of tongue-in-cheek moment**

    Even though the power was out everywhere here after I had first posted this morning, I still turned off the feed from the house to the workshop and then went to work looking for the neutral-to-ground continuity that should not have been there without the box being bonded ...

    ... and I did find a white wire in the lighting circuit that was lightly pinched between a porcelain light fixture and the grounded box to which that fixture is attached. So, I have corrected that problem ...

    ... and now I no longer have any continuity between the workshop-panel's neutral bar and ground unless/until the bonding screw is in place (which it now again is, of course). Overall, however, none of the above directly explains why/how an AFI breaker could/would work fine with plenty of load while the panel was *not* bonded and then trip over a 60W bulb while the panel *is* bonded ...

    ... and here is my theory: The neutral wire for the feed to the workshop does/did not have a perfect connection at the supply panel at the house -- it has a twisted connection to an extension wire connected to the neutral bar, and I have since added a nut to that years-old twist -- and then the pinched wire under the light in the workshop was not a complete-and-solid connection (such as the actual bonding screw at the panel would have provided if it had previously been there). So then, and prior to my bonding the panel, very little current actually went to ground through the pinched wire in the light box, and that means the AFI breaker detected no problem until I actually bonded the panel and more current actually did go directly to my ground rod rather than back through the feed's neutral wire's poor twist connection at the house.

    Does that make sense?!

    If so, that might answer my question as to the purpose of even having an AFI breaker.

    As an aside here: The EMT misunderstanding at the beginning of this thread initially left me thinking the workshop panel should *not* be bonded, and it was then really a good thing that the ground rod did accept most of the current from the black wire that was inadvertently shorted at the clamp at the top of the panel at that time. Barefooted or not, that EMT misunderstanding and its accompanying comment suggesting big trouble if the workshop panel *was* bonded would have left me receiving a full-voltage shock rather than a mere tingle if the ground rod had not done what it had done by instead taking almost everything on into the ground.

    None of us is perfect, of course, but we sure do need to be wary of mere assumptions and non-clear implications, eh?!
    Last edited by leejosepho; 10-11-2011 at 12:37 PM.

  6. #36

    Default

    How very funny that was and something you should say!

    I hailed from a long line of either welders or sparkies. I was 9 when I discharged my first capacitor. I loved playing with my dad's diodes and stripey colored-banded triodes. I learned early that tubes have a pressure which can implode. I knew what a schematic was before I saw the book, See Spot Run. In first grade when the teacher said to take out your reading book, I asked her, where she kept the schematics at. At 16 my dad said, I should take the exam for a third class license, I did. By the time I was 21, I had them all. He used to say, meaning this as a compliment to me, " that you are smarter than you look." I used to look in the mirror and wonder, is it the boobs? or he mascara? Then, I met this man. Who was what? A sparky... And, he was irish... My dad was so happy. He looked like a little leprechaun dancing. He wasn't racist at all, he just liked it he was irish. At my girlfriend's wedding he said, " I was talking to that tall kid, that tall skinny kid with the red hair, I think you should get to know him." And, what happened, I married him.

    So, their in the evenings, we would work on our new house. It was bought "as is." And, boy was it as is. My dad ripped out all the electrical in most of the house, and my husband ripped out the kitchen tracing a hot wire. I was out buying the right gauge wire, nuts, and pizzas.

    It was a match made in heaven. Between my husband and dad.
    God they loved him. If we had an argument, I was told, without them even hearing about it, I was at fault, not him!

    I rethought this marriage bit, lol. I was getting the shaft.

    We were a sparky family. We have sparky children.

    When he passed on, I was told by his coworkers and the military that God needed the best sparky so their wouldn't be anymore blackouts.

    We lit up the town that night better than any 4th of July Celebration.

    So, you see, in essence, I do have connections. That blackout was God's way of saying, " call a sparky!" Things happen for a reason.

    Call.

  7. #37
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    Lee

    Arc-fault devices are designed to detect arcs in the circuit. They will have some level of GFCI protection but not enough to protect someone from being hurt. Most will be in the 70 milliamp range or larger.

    You made a comment about current going to the ground rod which is not what is happening unless you have a lot of iron in the soil in your area.
    Quote Originally Posted by leejosepho View Post
    then really a good thing that the ground rod did accept most of the current from the black wire that was inadvertently shorted at the clamp at the top of the panel at that time.
    Around here most rods will have a resistance of 300 ohms or greater. At 120 volts this would only allow a maximum of 400 milliamps to flow through the rod and would not have any effect on the arc-fault device or any other device. You need to forget about the rod allowing current to flow and remember that the rods are installed to dissipate lightning not for current to flow on. The rod does not have any effect what so ever on the wiring system.

    Any and all current must return to its source and not even one electron will be leaked into earth. Earth will and does conduct current when the voltage is great enough to push current through the dirt.
    One fact that is always true is Ohmís Law which states that the voltage divided by the resistance will equal the current that flows. Using the requirement in 250.56 of 25 ohms do the math at 120 volts and then use the voltage on the primary of your transformer to see how much current will flow. If you donít know what it is in most cases it will be 7200 volts. At 120 it is just over 4 amps but at 7200 it will be over 200 but in any case it is trying to return to its source.

  8. #38

    Default

    Quote Originally Posted by leejosepho View Post
    ...and more current actually did go directly to my ground rod rather than back through the feed's neutral...
    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!


    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!

    This is a simplified version of how it all works, but I hope it helps.
    -rick

  9. #39
    Electrician ActionDave's Avatar
    Join Date
    Feb 2009
    Location
    Colorado
    Posts
    331

    Default

    Quote Originally Posted by leejosepho View Post

    ... and I did find a white wire in the lighting circuit that was lightly pinched between a porcelain light fixture and the grounded box to which that fixture is attached. So, I have corrected that problem ...

    ... and now I no longer have any continuity between the workshop-panel's neutral bar and ground unless/until the bonding screw is in place (which it now again is, of course). Overall, however, none of the above directly explains why/how an AFI breaker could/would work fine with plenty of load while the panel was *not* bonded and then trip over a 60W bulb while the panel *is* bonded ...
    AFCI breakers have ground fault sensing incorporated into them. However without a proper bond to the neutral conductor, they cannot sense a ground fault.

    ... and here is my theory: The neutral wire for the feed to the workshop does/did not have a perfect connection at the supply panel at the house -- it has a twisted connection to an extension wire connected to the neutral bar, and I have since added a nut to that years-old twist -- and then the pinched wire under the light in the workshop was not a complete-and-solid connection (such as the actual bonding screw at the panel would have provided if it had previously been there). So then, and prior to my bonding the panel, very little current actually went to ground through the pinched wire in the light box, and that means the AFI breaker detected no problem until I actually bonded the panel and more current actually did go directly to my ground rod rather than back through the feed's neutral wire's poor twist connection at the house.
    Close, but you could have a solid connection, on purpose or just as good as, and no breaker would trip if the circuit is fed from a panel that is missing a proper connection to the neutral. When you added the bond screw you made that connection and the breaker worked. The neutral is more properly known as the grounded conductor not because of anything to do with ground rods but because it is connected to the earth by the power company.

    If so, that might answer my question as to the purpose of even having an AFI breaker.
    They are intended to sense an arcing condition that could lead to a fire. They incorporate ground fault circuitry but are not to be substituted for gfci protection where required.
    As an aside here: The EMT misunderstanding at the beginning of this thread initially left me thinking the workshop panel should *not* be bonded, and it was then really a good thing that the ground rod did accept most of the current from the black wire that was inadvertently shorted at the clamp at the top of the panel at that time. Barefooted or not, that EMT misunderstanding and its accompanying comment suggesting big trouble if the workshop panel *was* bonded would have left me receiving a full-voltage shock rather than a mere tingle if the ground rod had not done what it had done by instead taking almost everything on into the ground.

    None of us is perfect, of course, but we sure do need to be wary of mere assumptions and non-clear implications, eh?!
    Yes indeed, as I was the one who asked about the bonding screw in the first place; assuming that the emt was continuous.

  10. #40
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    Quote Originally Posted by drick View Post
    Your ...............This is a simplified version of how it all works, but I hope it helps.
    -rick
    Good job, thank you

  11. #41
    Electrician ActionDave's Avatar
    Join Date
    Feb 2009
    Location
    Colorado
    Posts
    331

    Default

    Quote Originally Posted by drick View Post

    This is a simplified version of how it all works, but I hope it helps.
    -rick
    That was a good explanation, and much more colourful than mine.

  12. #42
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    Quote Originally Posted by jwelectric View Post
    You made a comment about current going to the ground rod which is not what is happening unless you have a lot of iron in the soil in your area.
    Maybe I do. While the black wire of the receptacle circuit was shorted in the clamp at the top of the panel and the panel was not bonded, that incoming leg showed no voltage when measured across to the neutral bar and the panel (and its ground bar) did show 120V when measured against the neutral bar ... and then measuring across the other incoming leg and the panel (ground bar) showed 240V ... and during all of that, I was only getting a small tingle between the panel and my bare feet when I touched the panel with my finger. So while I do understand the ground rod is not intended to be a catchall for stray current, it certainly did protect me from a full-voltage shock while that one incoming leg was directly shorted to the panel.

    As an overall recap here ...

    I came asking whether I could install a 30A breaker next to a 30A main;
    I was told I could and my mis-belief that my panel should not be bonded was confirmed;
    I shorted a wire in a clamp and my ground round spared me from a great shock;
    I corrected that problem (the short) and installed an AFI breaker incorrectly;
    Someone straightened me out about that and the breaker did not trip since the panel was not bonded;
    I bonded the panel and eventually found a shorted white wire under a light and a weak connection for the feed's neutral at the house;
    I still do not know precisely why the AFI had tripped, but it has been removed and we all agree my service entrance at the house definitely needs some work.

    I have ordered a retainer for the back-fed breaker in the workshop panel;
    I have installed a 30A receptacle for the welder and I have ordered a 30A breaker for that circuit;
    I have ordered a GFI breaker for the 20A circuit in the workshop so I can re-connect the outdoor receptacle;
    I will likely call the electrician again next week to see how far down his project list I might yet be.

    I thank everyone for the time spent being informative and helpful here ... and yes, Cookie, especially you!
    Last edited by leejosepho; 10-12-2011 at 05:51 AM.

  13. #43
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    Quote Originally Posted by leejosepho View Post
    I shorted a wire in a clamp and my ground round spared me from a great shock;
    This is a very untrue statement and has no merit at all. The ground rod did nothing to protect you from any shock unless there was a lightning strike at the time you touched the panel.

    The only thing that kept you from getting a bad shock was the resistance between the source and you.

  14. #44
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    Quote Originally Posted by jwelectric View Post
    This is a very untrue statement and has no merit at all. The ground rod did nothing to protect you from any shock unless there was a lightning strike at the time you touched the panel.

    The only thing that kept you from getting a bad shock was the resistance between the source and you.
    If what you are saying is true, then I should be able to go out there and put my finger on one of the incoming legs while standing barefoot on the concrete floor and still only feel a small tingle ... unless, of course, the pinch at the clamp was so very slight at the time that the breaker would not have tripped even if the panel *had* been bonded. The things I know for certain, however, are that the shorted leg showed no voltage at all when measured against the neutral bar, and that I had 240V between the other incoming leg and ground. I clearly understand you do not want people mistakenly depending upon a ground circuit to protect them from stray voltage, but the power from that shorted leg was going somewhere other than through its connected receptacle circuit (just beyond the pinch) that showed absolutely no voltage at all for the duration of the short.

    Tell me where you happen to believe I am wrong if that is all you can do, but help me understand if you can and will! Are you meaning to suggest all power coming in on that shorted leg simply stopped flowing at the point of the pinch except for "just enough" to give me a small tingle and to show voltage on my meter?

  15. #45
    DIY Senior Member BobL43's Avatar
    Join Date
    Mar 2011
    Location
    Long Island, NY
    Posts
    1,773

    Default

    Quote Originally Posted by leejosepho View Post
    If what you are saying is true, then I should be able to go out there and put my finger on one of the incoming legs while standing barefoot on the concrete floor and still only feel a small tingle ... unless, of course, the pinch at the clamp was so very slight at the time that the breaker would not have tripped even if the panel *had* been bonded. The things I know for certain, however, are that the shorted leg showed no voltage at all when measured against the neutral bar, and that I had 240V between the other incoming leg and ground. I clearly understand you do not want people mistakenly depending upon a ground circuit to protect them from stray voltage, but the power from that shorted leg was going somewhere other than through its connected receptacle circuit (just beyond the pinch) that showed absolutely no voltage at all for the duration of the short.

    Tell me where you happen to believe I am wrong if that is all you can do, but help me understand if you can and will! Are you meaning to suggest all power coming in on that shorted leg simply stopped flowing at the point of the pinch except for "just enough" to give me a small tingle and to show voltage on my meter?
    Interesting questions, but you need to be awayre that it only takes a few milliamps (maybe 5 or so ma) passing through the heart of the average person to be a widow maker. 5ma is almost nothing otherwise. not even enough to light up a little 4 watt incandescant nightlight bulb.
    What you felt can be measured with a meter
    I am definitely not a pro plumber, but I am a pro crastinator

Similar Threads

  1. Wires too short to reach new load center.
    By Mindz i in forum Electrical Forum discussion & Blog
    Replies: 26
    Last Post: 01-01-2011, 04:47 PM
  2. Load center replacement
    By philbob57 in forum Electrical Forum discussion & Blog
    Replies: 7
    Last Post: 08-29-2009, 08:04 PM
  3. Interpreting labels in Load Center
    By Nate R in forum Electrical Forum discussion & Blog
    Replies: 16
    Last Post: 08-25-2008, 08:59 PM
  4. The load center game
    By KAdams4458 in forum Electrical Forum discussion & Blog
    Replies: 27
    Last Post: 08-20-2008, 07:37 PM
  5. Load Center Wiring Questions
    By Lakee911 in forum Electrical Forum discussion & Blog
    Replies: 17
    Last Post: 02-10-2008, 09:09 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •