Hi all,

I would like to have your view regarding external grid short circuit scenarios in Arc Flash calculations. I have some doubts about how this issue should be addressed.

What should I do if there is no info about the available short circuit power in the grid?

As far as I understand, considering only hypothetical maximum and minimum short circuit scenarios for calculation I may not be achieving the “Worst Case� incident energy scenario. The reason is that there may be some intermediate Scc scenarios in which the combination of FCT + Icc may lead to a higher Incident Energy. So the correct approach may be doing a sweep with different values. There is also some scientific literature with conclusions pointing in the same direction.

Similar happens when the utility gives you the data: what about short circuit intermediate scenarios?

How do you see it?

Thanks for your support.

Regards,

Up!

I think Jim has an article somewhere about this topic.

Mike