Arc Flash Boundary (AFB) definition?

Arc Flash Boundary (AFB) definition?

• A. The distance for Siren audible range.
• B. The maximum voltage rating of the system.
• C. The range of the wireless sensor.
• D. Safe approach distance from energized equipment or parts; NFPA 70E establishes default arc flash boundary at 4 feet for low voltage.

Answer: (D)

Arc Flash Boundary is the safe approach distance from energized equipment or parts. It’s a radius inside which an arc flash could cause a second-degree burn to a person, so within that boundary the job must be planned with appropriate PPE and methods. NFPA 70E gives a default boundary of about 4 feet for low-voltage systems, but the actual distance can vary based on voltage, available fault current, equipment, and fault conditions; the boundary can be calculated or adjusted accordingly to match the specific situation. The other options describe things like alarm ranges, voltage ratings, or sensor ranges, which aren’t about the safe distance from energized parts.

Arc Flash Boundary is the safe approach distance from energized equipment or parts. It’s a radius inside which an arc flash could cause a second-degree burn to a person, so within that boundary the job must be planned with appropriate PPE and methods. NFPA 70E gives a default boundary of about 4 feet for low-voltage systems, but the actual distance can vary based on voltage, available fault current, equipment, and fault conditions; the boundary can be calculated or adjusted accordingly to match the specific situation. The other options describe things like alarm ranges, voltage ratings, or sensor ranges, which aren’t about the safe distance from energized parts.