I am working on the justification for switching a 480V board from normal to alternate feed. My load breakers are rated at 30kA but my short circuit current, per ETAP, is 38kA. I'll try to make my intro short. I have an existing ETAP calc that says this switch is ok because there is a 60% diversity factor on the boards that will feed this SC. My question is about the application of diversity to SC. I have never seen this done before. Is it permissible to apply a diversity factor on a board to its contribution to a short circuit on a different board?
In other words, if I have 480V board A receiving a SC contribution from 480V board B of 10kA (from ETAP whoch does not take into account any diversity durng SC), and board B has a diversity factor of 60%, can I then say that the SC contribution to board A is 6kA? Is there any white paper or anything that leads to this justification?
In other words, if I have 480V board A receiving a SC contribution from 480V board B of 10kA (from ETAP whoch does not take into account any diversity durng SC), and board B has a diversity factor of 60%, can I then say that the SC contribution to board A is 6kA? Is there any white paper or anything that leads to this justification?