Steven Sallwasser
Member
- Location
- Arnold, MO
I am doing an arc flash calculation using PTW32 software. I have a 25 KVA transformer from 480V to 120V and the program is telling me that the available fault is 900A, but the arc-flash protection required is a level 3. This seems to make no sense to me as to why the arc flash level would be so high. It shows the time delay for the breaker to trip of two seconds. Since the bus arcing fault is 900A on a 100A breaker, I would expect the breaker to trip in a much shorter period of time than 2 seconds. If you could enlighten me as to what I may be doing wrong, I would appreciate it.