Here find some attached circuit of three phase cabinet which operation voltage is 400V /415V and have operated current 800A, fault current for 1 sec is 46 KA and have incoming and outgoing links with one phase Lighting and socket. I want to know is there some method that one can calculate the short circuit current per second that the bus-bar can bear. Moreover I also want to calculate the short circuit current for 3 second. Is there any relation between the current and time in this case (directly, or Inversely Proportion) ? Please provide me the formula if exist to calculate short circuit current (fault-current) in any time.