User Tag List

Page 12 of 12 FirstFirst ... 2 10 11 12
Results 111 to 113 of 113

Thread: Ground fault- Why doesn't anyone get shocked?

  1. #111
    Join Date
    Jan 2008
    Posts
    9,784
    Mentioned
    0 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by mbrooke View Post
    Remember, I just said you can show me the results at 5 cycles. Lets first determine if 5 cycles is ok or not ok.
    Let's say no for the chart that goes along with the neutral switching scheme. Now what?

    If you install the device you propose, it is a single point of failure. You claim a single point of protection is not good enough for one scheme but is good enough for another scheme.

    You can't have it both ways.

    Quote Originally Posted by mbrooke View Post
    I have always been taught to take BF into account. I normally bite my tongue, but you are going to have to tell a half dozen ISOs, NERC, FERC, and countless utilities they are doing it wrong.
    You are missing the point.

    Also, since you are name-dropping: Tell me how many of those do not maintenance their breakers because there are too many of them and/or because some of them are difficult to switch around?

    Quote Originally Posted by mbrooke View Post
    True- I'll let Tony fill us in.
    Have you contacted him?
    BB+/BB=?

  2. #112
    Join Date
    Jan 2011
    Location
    United States
    Posts
    9,373
    Mentioned
    1 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by mivey View Post
    Let's say no for the chart that goes along with the neutral switching scheme. Now what?
    What neutral switching scheme


    I'm asking you to use this chart on a 5 cycle clearing MGN system:









    60479-1 is the basis of what is considered safe vs unsafe and plays a role in just about every aspect of an electrical system.





    If you install the device you propose, it is a single point of failure. You claim a single point of protection is not good enough for one scheme but is good enough for another scheme.

    What device? The drawing I'm showing you has no device other then a human removable link in the underground feed version. The LV neutral is separate from the MV neutral and only a person can connect them together.


    You can't have it both ways.

    You are missing the point.

    Also, since you are name-dropping: Tell me how many of those do not maintenance their breakers because there are too many of them and/or because some of them are difficult to switch around?
    Thats my point all along. You may have small utility that has time to test every breaker on a 3 year (or the like cycle) but try being something the size ComEd, National Grid or Dominion. In such a case these guys must assume breaker failure for distribution breakers.



    Have you contacted him?

    Yup- got this reply back:


    Tony S
    Senior Member


    Join DateJul 2013LocationResting under the Major Oak UKPosts1,346Mentioned0 Post(s)Tagged0 Thread(s)

    Re: Request

    For the LV and MV earths to be linked the LV side earth nest on its own has to be <1Ω.
    Between 1Ω and a maximum of 10Ω the link is removed and the 8 metre rule comes in to play.
    >10Ω more work is needed on the earth nest to get it <10Ω.

    BTW, is there a site I can download the NEC from?

    The reports of my death are greatly exaggerated.

  3. #113
    Join Date
    Jan 2011
    Location
    United States
    Posts
    9,373
    Mentioned
    1 Post(s)
    Tagged
    1 Thread(s)
    This being what determines the two being bonded together vs not bonded together:


    For the LV and MV earths to be linked the LV side earth nest on its own has to be <1Ω.
    Between 1Ω and a maximum of 10Ω the link is removed and the 8 metre rule comes in to play.
    >10Ω more work is needed on the earth nest to get it <10Ω
    .

Posting Permissions

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