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. See the definition for condition of maintenance in Article 100.

• A. True
• B. False
• C. Not specified
• D. Only for AC systems

Answer: (B)

The important idea here is how arc flash PPE decisions are made and what maintenance actually guarantees. The arc flash PPE category method provides a way to select PPE based on category values tied to protective-device performance, using data such as the clearing time of the upstream OCPD. However, that approach does not by itself give a precise Arc Flash Boundary, which comes from the incident energy at a given working distance. That boundary (the AFB) is established from the actual energy that could be released during a fault, which depends on the real short-circuit current and the actual clearing time of the protection system.

Even when the protecting OCPD and the panelboard are properly installed and maintained, you cannot rely on “typical” clearing times alone to determine the AFB and PPE using the category method. Maintenance ensures the equipment can perform as designed, but the category method uses generalized or manufacturer data and may not reflect the exact conditions of a specific installation. To accurately determine the boundary and select PPE, you typically need an incident energy analysis (or a PPE category approach with adequately verified data), not just a rough, typical clearing-time estimate.

So the statement is false because the Arc Flash Boundary and PPE selection should be based on a validated hazard analysis, not solely on OCPD typical clearing times even if maintenance is up to date.