Circuit Breakers not selective

[Newbie2000]

Hi All,

I have a situation in hand, the client asks for certain protection coordination ( breaker curve) for our switchboard circuit breaker because at present situation the client generator circuit breaker will trip before our switchboard and it is not acceptable.

Now our Vendor has replied us saying they can manipulate the curve settings with changing the dip switch settings and also says that our circuit breakers will no longer be selective?

can anyone advise me, what does it mean by no longer selective?

Thanks a lot.
regards

 

[DistCoop]

It's an NEC term

http://www.eaton.com/Eaton/Products...s/SelectiveCoordination/index.htm?wtredirect=

http://www.eaton.com/selectivecoordination

 

[VTer]

If the breaker is no longer selective, I would assume it means it does not selectively coordinate which therefore does not solve your problem. Is this an emergency generator and where is this client located? You have to look at time current curves of the entire system and also ensure that the generator is protected.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic ù and this we know it is, for certain ù then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". û Nikola Tesla