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Breaking capacity of a circuit breaker in MVA

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  1. cwbrennert is offline Junior Member Pro Subscriber
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    Breaking capacity of a circuit breaker in MVA

    27. The breaking capacity of a circuit breaker in MVA (3 phase) is given by
    Your Answer: rated service voltage x rated symmetrical current
    Correct Answer: 3.5 x rated service voltage x rated symmetrical current
    Help: Circuit Breaker Breaking Capacity

    now if you go to the link provided by the hint you find this

    "Generally Breaking Capacity in MVA is given as (3)1/2 x rated voltage in kV x rated breaking current in kA"

    except that the (3)1/2 is really (3)^1/2 which is the square root of three, not 3.5. I answered what I did because it seemed like the best answer given the choices. So who got this wrong TestGuy or NETA? I have used you site to study for the first two exams and this sort of thing has come up a couple of times now.

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  3. mcmahanrf is offline Junior Member Pro Subscriber
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    Testguy messed this up

    Your correct, that is a typo on test guys part. It should by square root of 3. Sadly this is not a possible answer.


    Quote Originally Posted by cwbrennert View Post
    27. The breaking capacity of a circuit breaker in MVA (3 phase) is given by
    Your Answer: rated service voltage x rated symmetrical current
    Correct Answer: 3.5 x rated service voltage x rated symmetrical current
    Help: Circuit Breaker Breaking Capacity

    now if you go to the link provided by the hint you find this

    "Generally Breaking Capacity in MVA is given as (3)1/2 x rated voltage in kV x rated breaking current in kA"

    except that the (3)1/2 is really (3)^1/2 which is the square root of three, not 3.5. I answered what I did because it seemed like the best answer given the choices. So who got this wrong TestGuy or NETA? I have used you site to study for the first two exams and this sort of thing has come up a couple of times now.

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