Weird questions about short circuit current capacity

[khanpk]

Hi friends ,

today we are just general talking with my boss. and he asked me a question . and that is,

if we have equipment that is rated short circuit current is 40kA. for 1 sec. and if we must have to use that same equipment for 3 sec time. that how much short circuit current they can sustain for 03 sec time, definitely below than 40kA. but how much with respect to time ie 3 sec. let say 10kA , 20kA , 30kA, or 39.8kA. ..

this is completely just discussion not practically by any mean please.

thanks

 

[phinds]

Hi friends ,

today we are just general talking with my boss. and he asked me a question . and that is,

if we have equipment that is rated short circuit current is 40kA. for 1 sec. and if we must have to use that same equipment for 3 sec time. that how much short circuit current they can sustain for 03 sec time, definitely below than 40kA. but how much with respect to time ie 3 sec. let say 10kA , 20kA , 30kA, or 39.8kA. ..

this is completely just discussion not practically by any mean please.

thanks

Completely indeterminate given the information you have provided. It's going to depend on the specifics of the particular equipment.

 

[jim hardy]

i suspect boss is leading you to self educate on this subject

http://ep-us.mersen.com/fileadmin/catalog/Literature/Application-Guidelines/ADV-P-Application-Information-Let-Thru-Current-and-I2t.pdf

many devices give an I^2t rating so you can choose a breaker or fuse to protect it. Search also on "fuseology"

 

[Jeff Rosenbury]

For something that burns, heat is developed by I²R. Lots of equipment will fail in this mode, but it's not the only failure mode.