I-line breaker tripped

[Davebones]

Had a fuse in a I-LINE busway blow. This was a old RK-5 fuse . When it blew it physically open and caused a phase to phase short on the line side of the bus switch almost causing the switch to blow of the bus . ( sounded like a hand grenade ) The 400 amp I-line breaker saw this and tripped as designed . We replaced the bus switch ,meggered everything and re-energized the bus . My question is how do we decide if we need to replace the 400 amp breaker . I understand they are designed to only handle so many faults like this ....

 

[Jraef]

They have to clear a fault and be capable of being reset at least once, but it's always a good idea to at least have them tested after an event like that. The energy it takes to rupture a fuse rated for 200kAIC is at the very least, "significant" with respect to the breaker feeding it!

 

[mxslick]

Why take a chance of this happening?

Why take a chance of this happening?

Take a look here at THIS THREAD (see post#8) and I think you'll agree that replacement of the breaker would be the wise choice, especially after the magnitude of your event. (Thanks to member Brian John for the picture.)