bruinfan wrote:
I have (4) 160kVA UPS feeding the same bus. On the line side of the (4) UPS the short circuit magnitude is 24kA. However, the short circuit mag. on common bus on the load side of the (4) UPS is significantly less; 0.615kA. So my question is should I be seeing such a significant drop in my short circuit magnitude?
On the inverter side - Yes. Typically the short circuit current from the inverter is around 2 times the full load current. If there is a static and / or maintenance bypass, then you would want to consider Murphy. i.e. his law and the possibility of the arc flash occurring in bypass mode.