Interrupting Ratings: Air Rated Breakers Explained

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Discussion Overview

The discussion revolves around the concept of interrupting ratings for air rated breakers, including their significance, testing, and implications when these ratings are exceeded. The scope includes technical explanations and practical applications relevant to electrical wiring and circuit breakers.

Discussion Character

  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant confirms that air rated breakers do have interrupting ratings, which can range from 22 to 65 kA.
  • Another participant expresses gratitude for the information on interrupting ratings, noting a lack of detail in their class materials about the consequences of exceeding these ratings during a short circuit.
  • The same participant seeks further clarification on what specifically happens when a circuit breaker fails due to exceeding its interrupting rating.
  • A separate comment mentions the passing of a notable figure in the field, which may indicate a shift in available expertise or resources.

Areas of Agreement / Disagreement

Participants generally agree that air rated breakers have interrupting ratings, but the discussion remains unresolved regarding the specific outcomes when these ratings are exceeded.

Contextual Notes

The discussion highlights a gap in educational resources regarding the failure mechanisms of circuit breakers under overload conditions, indicating a need for more detailed information in instructional materials.

Josh111
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do air rated breakers still have interrupting ratings?
 
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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.
 
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.
 
Unfortunately, Negitron (Michael Bell) died in September.

There was a note about this on this page, but it has now gone.
 
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