How to Implement Series Rating for Breakers

In the example below, notice that the available fault current at BUS-10 is 32.113 kA.



The interrupting rating of BL-18 (GE THHQB) is 22 kA, which isn't enough for this fault current. 
 


 The upstream breaker is BL-4 (GE Spectra), shown below.



To see if we can use series rating for BL-18, we need to look in the library.



The combination of the two breakers can handle up to 65 kA of fault current. To apply this to BL-18, we need to open the Short Circuit tab of BL-18, select Series, and then click Calculate



Click OK to save the new rating. Device duty uses this value to create reports. 65 kA is high enough to handle the short circuit current.


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