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Home > Archive > Electrical code Compliance > June 2005 > Cycling of Circuit Breakers
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Cycling of Circuit Breakers
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| Is there any code, standard, reference, or documentation that states
how many times a circuit breaker can be cycled safely after it has
tripped? Also, are there a set number of times a circuit breaker can
trip before its overcurrent properties begin to degrade?
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"iscb" <iscb@yahoo.com> wrote in message
news:1114009092.517923.292610@g14g2000cwa.googlegroups.com...
quote:
> Is there any code, standard, reference, or documentation that states
> how many times a circuit breaker can be cycled safely after it has
> tripped? Also, are there a set number of times a circuit breaker can
> trip before its overcurrent properties begin to degrade?
>
For IEC standard breakers, IEC947-2.
It all has to do with the Icu = ultimate breaking cappacity and the
Ics=service breaking cappacity , the Ics is usually expressed as a %age of
the Icu value.
eg a device with an Icu of 45kA and an Ics value of 75% can (in theroy)
handle 34kA faults and still be able to function
although i prefer HRC fuse links myself
more reading here :-
http://www2.schneider.co.uk/seweb2/...ID/JPAE-58FMVJ/$file/ECT150.pdf
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