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Thread: Question on article 440.22 (a)

  1. #1
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    Question on article 440.22 (a)

    440.22 (a) gives me the impression that we aren't supposed to use 225% to size the overcurrent protection device unless 175% is not sufficient for the starting current. However, in Mike holts 2014 electrical exam prep book all of the protection sizing calculation examples for motor compressors use 225%.. so what am I missing?? I know I can use the nameplate most of the time and I Probably won't see this on my upcoming test but I would really like to know thanks!!

  2. #2
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    Welcome.

    If the question asks for the maximum overcurrent protection rating, using 225% is correct.
    I will have achieved my life's goal if I die with a smile on my face.

  3. #3
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    Smart-- go to sleep---

    Seriously, when a question came up a long time ago you stated we should always use the rule not the exception when answering a question. Is this not the same?

  4. #4
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    Quote Originally Posted by Smart $ View Post
    Welcome.

    If the question asks for the maximum overcurrent protection rating, using 225% is correct.
    The questions ask for the required protection device.

  5. #5
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    Quote Originally Posted by Dennis Alwon View Post
    Smart-- go to sleep---

    Seriously, when a question came up a long time ago you stated we should always use the rule not the exception when answering a question. Is this not the same?





    In this case, 225% isn't written as an exception to that section. It is actually stated right in the section. Test question authors will likely consider that fair game.
    I will have achieved my life's goal if I die with a smile on my face.

  6. #6
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    Found it

    Found some other calculations in the same book using 1.75 and 2.25 if that doesn't work.. so guess that is right. Those examples just confused me..

  7. #7
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    Poor question as worded I would say. Without "maximum" being in the wording anything under 226% is an acceptable level code wise.

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