Isolator Icw - 50KA but different durations

[MoBawy]

Hi all, 

I'm using this switch disconnector 

31340 - switch disconnector, Compact INS2500, 2500A, standard version with black rotary handle, 3 po...

and the Icw assigned with it is snipped below

Can someone shed light on why / how does it have Icw = 50KA at different durations? and which one should I use for calcs

[Gregoire_Brun]

hello @MoBawy 

All depends about the triping time seting you select for associate breakers.

As I know generaly for IEC 61439 certification generaly it's time at 1s witch are requested but it depends about customer specification...

[MoBawy]

but I understand there is a relations that is generally valid up to 3 sec which is I^2t = constant

so if a device can have 50KA for 0.5S .. it shouldn't be able to tolerate 50KA for 1S 

For example 50KA for 1s and 30KA for 3s  is understood to me.. but not 50KA for 0.5s and ALSO 50KA for 1s .. it should be less???

[Gregoire_Brun · Accepted solution]

hello @MoBawy the certified value for this product was 50kA for 1s and performence at 0.5s was added without calculation update, maybe it's possible that Icw was better at this time but wa haven't tested and certifiy the limit of the product at this time so by security we have include same curent at this time.