How to Implement Series Rating for Breakers

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

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

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

To see if we can use series rating for BL-18, we need to look in the library.  First, select the upstream breaker type from the left of the library.
Breaker type selection in library

Then select the Series Rated Devices tab and locate the downstream breaker type. 
Breaker series rating information

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. 
Breaker short circuit series selection

Then click Calculate and a message is displayed confirming the selection.
Series rating confirmation
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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