instantaneous trip

[teke]

If a breaker trip on transformer inrush current just after closing, is it an arc flash hazard?

 

[dpc]

Not if the breaker is rated to interrupt current of that magnitude. It is a breaker sizing/setting problem.

David Castor

http://www.cvoes.com

 

[ndondo]

it cant be the arc that trips the breaker, if you do have an arc protection relay on your breaker then you need to check
the status of your arc prot relay and also check your settings on your o/c and e/f protection relay there is a
possibility that your setting are too low on the relay.

 

[lume7006]

Hello,

I think that if the circuit breaker tripped just after being closed there could be some answers, none related to arc flash:

1) The setting of the instantaneous is below the inrush current.
2) Sometimes, the instantaneous of ground elements is also tripped, it may be inrush or also a bad setting or even sometimes a wrong CT ratio.

Best Regards