What is the FPB distance for voltages at 5,000 V or greater?

• A. 4 feet
• B. 11 ft
• C. 13 ft
• D. 20 ft

Answer: (C)

The concept here is the Flash Protection Boundary, which is the distance from energized equipment within which an arc flash could deliver enough energy to cause a burn. This boundary grows with voltage because higher voltages can produce more severe arcs, so you need to stay farther away to reduce incident energy to a safe level and to determine when arc-rated PPE is required.

For voltages at or above 5,000 V, the FPB is 13 feet. This distance corresponds to the point where the potential incident energy is low enough to be managed with appropriate PPE and procedures, assuming typical fault currents and clearing times. Staying beyond this boundary minimizes burn risk during arc flash events.

The other distances don’t fit the high-voltage guideline: 4 feet is commonly associated with much lower voltages, 11 feet is not the standard boundary for this voltage level, and 20 feet is more conservative than the standard FPB for 5 kV or greater.