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Thread: 250.122(B) Increase in size - were did the change come from.

  1. #21
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    Quote Originally Posted by Sierrasparky View Post
    Charlie I see your point. I'll give another. So now you have a #10 because of conductor heating derating. How long a run can you make with the #10's on a 20 amp breaker before you run into fault issues because you have only a #12 EGC.
    Again, how do you write a code rule to cover that. Show me the words.
    ...
    Anyway, I see that as long as the CMP feels warm and cozy with a ROP then it's a done deal.
    The often make changes based on the comments.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  2. #22
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    No, I did not say write a rule to make a EC hire a PE to deal with every day EGC sizing.
    The PE is for Validating my CODE. I just don't think that a EC from Kalifornia is going to have enough weight to make it happen .
    The change would need to PE and peer review for it to work in my opinion.

  3. #23
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    Quote Originally Posted by Sierrasparky View Post
    ...I just don't think that a EC from Kalifornia is going to have enough weight to make it happen .
    ...
    All it takes is a well written proposal with a solid technical substantiation.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  4. #24
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    Quote Originally Posted by don_resqcapt19 View Post
    All it takes is a well written proposal with a solid technical substantiation.
    I respectfully disagree. There is a appearance of political and authoritative preference in these things.
    I believe that if this is going to change it will need the proper vetting.
    Right now I don't even know what language to use that we here can have consensus on.

  5. #25
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    Quote Originally Posted by Sierrasparky View Post
    I respectfully disagree. There is a appearance of political and authoritative preference in these things.
    I believe that if this is going to change it will need the proper vetting.
    Right now I don't even know what language to use that we here can have consensus on.
    Have you ever submitted a proposal or comment? How many ROPs (TCRs) and ROCs (TCDs) have you read?
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  6. #26
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    You must of failed an inspection, huh?

  7. #27
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    Nope, No failed inspection.
    Just was not aware of the interpetation here on this forum. Have a NEC handbook and it states " for voltage drop upsizing.
    I see the complete stupidity of the current interpetation.

    As far as the ROP's read I feel since the many failures thus far to correct the wrong it will take some vetting that I do not posses by myself.

  8. #28
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    Quote Originally Posted by Sierrasparky View Post
    ...
    Just was not aware of the interpetation here on this forum. Have a NEC handbook and it states " for voltage drop upsizing.
    I see the complete stupidity of the current interpetation.
    There is no interpretation involved...the voltage drop wording was removed. The only interpretation is what is the "normal" size of the ungrounded conductor.
    The handbook is not the code...the code is the code and it says what it say.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  9. #29
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    Quote Originally Posted by don_resqcapt19 View Post
    There is no interpretation involved...the voltage drop wording was removed. The only interpretation is what is the "normal" size of the ungrounded conductor.
    The handbook is not the code...the code is the code and it says what it say.
    If most were ok with the current interpetation then there would be no reason to change it then.


    Also the NEC should not allow a book of interpetations to be published with thier name all over it. I don't give a crap that there is a clause in the inside cover. Tell me what the purpose of the book is for then. Oh it is for humor , coffee table reading, exersising your eyes.
    get real.

  10. #30
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    Quote Originally Posted by Sierrasparky View Post
    So now you have a #10 because of conductor heating derating. How long a run can you make with the #10's on a 20 amp breaker before you run into fault issues because you have only a #12 EGC?
    I calculate that at about 210 feet (one way circuit length), but it might be OK even for a 420 foot (one way) circuit. By contrast, if you used #10 for both the ungrounded and the EGC, you might not have trouble clearing a fault unless the circuit length exceeded 540 feet. But of course, you might be dealing with equipment performance issues with a circuit that long anyway, if you only used #10 for the ungrounded conductor.

    So in light of this one, limited example, there is no technical reason that we would need to upsize the EGC from #12 to #10, in that any circuit that is not so long that it causes VD issues at the end of the line would be able to clear a fault in a reasonable time, even with a #12 EGC. Did I mention already that I didn't like this rule?
    Charles E. Beck, P.E., Seattle
    Comments based on 2014 NEC unless otherwise noted.

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