I’ve run a 3 Phase short circuit study but I have protective devices in my TCC drawing that still have Isc Amps of 200,000A. Why don’t they pickup the calculated bus fault current?
There are several potential causes of this problem.
-If you have a single phase device (cable or transformer) in the system and are running the balanced short circuit study, the buses down stream of that component will not be included in the fault stud. The resulting message in the Study Messages dialog is below.
System: Single Phase/Unbalanced components are found in the system
System: Single Phase/Unbalanced portion will be ignored in balanced study
To solve this problem, change the appropriate components into 3-phase components and re-run the balanced short circuit study.
-If you run the AFAULT study and under the TCC Settings/Fault Current tab you select a fault current from the comprehensive study, your Bus Isc will remain at 200,000A. Select the appropriate fault current from the Fault Type list box, in this case, one starting with "ANSI".
-If you have a single phase device (cable or transformer) in the system and are running the balanced short circuit study, the buses down stream of that component will not be included in the fault stud. The resulting message in the Study Messages dialog is below.
System: Single Phase/Unbalanced components are found in the system
System: Single Phase/Unbalanced portion will be ignored in balanced study
To solve this problem, change the appropriate components into 3-phase components and re-run the balanced short circuit study.
-If you run the AFAULT study and under the TCC Settings/Fault Current tab you select a fault current from the comprehensive study, your Bus Isc will remain at 200,000A. Select the appropriate fault current from the Fault Type list box, in this case, one starting with "ANSI".