Iarc in arc flash calculation

[Kevin Mejia]

In the IEEE 1584 through the fault current we calculate the Iarc and Iarc reduced, and then the incident energy. But, in the NFPA 70E, I didn't see anything like Iarc reduced, just fault current. This concept is only in the IEEE 1584? The table 130.7(C)(15)(a) in the NFPA make some generic considerations, these are made just with fault current? This is relevant to me because the clearing time depends on the protection device, and I need to adjust the instant protection in this, but I don't know if I should use the Iarc reduced (more conservative) or just the fault current.
Thanks in advance.

 

[dpc]

NFPA 70E does not stipulate how to calculate the incident energy. The table you reference is for use if you're using the NFPA 70E "Categories Method". If you're calculating using IEEE 1584, then you do not reference these tables at all. Two completely different methods. The fault currents listed in the 130.7(C)(15)(a) are maximum fault currents for which the tables can be used. So these are bolted fault currents.

Long story short, you need to use your calculated arcing current if you are adjusting settings to reduce incident energy.