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Interrupting ratings

  1. Aug 1, 2009 #1
    do air rated breakers still have interrupting ratings?
  2. jcsd
  3. Aug 1, 2009 #2


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    Yes, of course they do. I work with several types of breakers with interrupt ratings from 22 to 65 kA. It's an important rating for power equipment because exceeding it can cause the contacts to become fused, rendering the breaker useless and putting lives and equipment at risk.
  4. Nov 7, 2009 #3
    I want to thank you for post regarding the interrupting rating because I am currently in a class on commercial electrical wiring and there is a large section on interrupting rating for circuit breakers in our book covering things like how they are tested and the various ways to install breakers in series assemblies with main and branch, but for some odd reason the book fails to detail what exactly happens when a short circuit actually exceeds a breaker's interrupting rating.

    I naturally assumed that the circuit breaker would fail in some respect, but couldn't find any reference to exactly what the outcome might be besides a broken breaker. So thank you for your post.

    Any more details you might add would be appreciated regarding the interrupting rating and what happens when a short circuit exceeds the breakers rating.
  5. Nov 9, 2009 #4


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    Unfortunately, Negitron (Michael Bell) died in September.

    There was a note about this on this page, but it has now gone.
    Last edited: Nov 10, 2009
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