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Thread: Electrical Exam Prep Help?

  1. #1
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    Electrical Exam Prep Help?

    Is this the correct forum to seek help getting through the Mike Holt 2017 NEC Exam Preparation Course?

  2. #2
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    Sure, what can we help you with?
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  3. #3
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    I assume this is what you are questioning. It is pretty straightforward but how one is expected to enforce this is another question

    110.14(D) Installation. Where a tightening torque is indicated as a
    numeric value on equipment or in installation instructions
    provided by the manufacturer, a calibrated torque tool shall be
    used to achieve the indicated torque value, unless the equipment
    manufacturer has provided installation instructions for
    an alternative method of achieving the required torque.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  4. #4
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    Quote Originally Posted by infinity View Post
    Sure, what can we help you with?
    Preparing to take a Master Electrician Exam, just looking for some help along the way. I'll be posting questions as needed to get through the course, currently in Unit 6 - Conductor Sizing and Protection Calculations.


  5. #5
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    Quote Originally Posted by Dennis Alwon View Post
    I assume this is what you are questioning. It is pretty straightforward but how one is expected to enforce this is another question
    That's my user name, not a question.

  6. #6
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    Quote Originally Posted by 110.14(D) View Post
    That's my user name, not a question.

    Hahaha you got me-- didn't catch that
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  7. #7
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    Quote Originally Posted by 110.14(D) View Post
    Preparing to take a Master Electrician Exam, just looking for some help along the way. I'll be posting questions as needed to get through the course, currently in Unit 6 - Conductor Sizing and Protection Calculations.

    We are anxiously waiting
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  8. #8
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    Feeder Sizing @ 90°C

    Page 249 Figure 6-16

    If 300A continuous load @ 100% with 90°C wire on 90°C terminals is permitted, using the 90°C column for XHHW wire the first conductor size over 300A is 300kcmil at 320A. Why is the answer for this example 400 kcmil @380A? I thought I understood this concept in the 2017 NEC Handbook Section 215.2, but I can't get the right answers in any of the examples in the Exam Prep Book.

    What am I missing?

  9. #9
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    300 x 125%= 380

    The question seems to imply that the breaker is rated 100% but if that is not the case then 400 kcm is correct. The wording, to me, is a bit off.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  10. #10
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    I failed to mention the 400A breaker.

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    The point of the example seems to be that 90° wire can be used at full 90° ampacity on 90° terminals permitting a smaller size for that segment. 125% full load doesn't apply to that 90° segment, but I completely missed that 300 kcmil XHHW (320A @ 90°C) would be enough for the load but undersized for the breaker.
    Last edited by 110.14(D); 04-02-18 at 04:58 PM.

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