What is the FPB distance for voltages from 700 to 5,000 V?

• A. 4 feet
• B. 11 ft
• C. 13 ft
• D. 15 ft

Answer: (B)

Flash Protection Boundary is the distance from energized equipment within which an arc flash could deliver a level of energy that requires arc-rated PPE and strict safety controls. For voltages in the 700 to 5,000 V range, the standard FPB distance is 11 feet. This boundary is set so that, at or beyond it, the incident energy falls to a level where workers can be protected with appropriate PPE, typically around the 1.2 cal/cm² threshold used in arc-flash practices. Therefore, 11 feet is the distance used in this voltage band to establish safe access and required protective gear. The other distances correspond to different voltage ranges (too short for this range, or more conservative/for higher voltages), which is why 11 feet is the best choice here.