Is there really any way a 480V panel fed by a 700kva trans is going to sit there and arc for 1000 seconds? It's got a 1600A breaker but the software is telling me its only seeing 350A fault, so its not tripping. How realistic is this?

Rated current on a 700 kVA (odd size!) transformer is 842A at 480V. The fault current is not reasonable.

1600A MCB is a bit oversized. Does it have a rating plug by which you can change the trip value. A trip value of 1200 or even 1000 amps would shift your trip curve. Even without this, your transformer should be 5 to 6% impedance, which means your fault current should be 15,000 amps. With a finite bus around 10 to 12 thousand amps. So you have something wrong.

Maybe the software is looking at the incident energy on the line side of the MCB and is reporting the current in a protective device on the primary of the transformer.

If the software is saying 350A fault, I assume there is a length of feeder cable that should be protected by a small circuit breaker. I suspect you are missing a circuit breaker from your study (just guessing).

Gary B

Deprico: If you're using Easypower, jghrist found your problem. That's just how it presents the results.

See the report «Upstream Trip Device Name».