The conditions of this application would permit using the arc flash PPE category method to determine the AFB and select arc flash PPE based on the OCPD typical clearing times, assuming the protecting-OCPD and the 480-volt panelboard have been properly installed and maintained.

• A. True
• B. False
• C. Not enough information
• D. Depends on the system

Answer: (A)

The arc flash PPE category method uses how long the protecting OCPD takes to clear an arc fault to estimate the incident energy, which then determines both the arc flash boundary and the required PPE category. When the protecting-OCPD and the 480-volt panelboard are properly installed and maintained, the clearing-time data are reliable, so you can base the AFB and PPE selection on those times. This approach is an accepted way to set protection levels under NFPA 70E, provided the equipment is in proper working condition and the protection devices perform as expected. Under those conditions, using the arc flash PPE category method to determine the AFB and select PPE is valid.