Which standard defines the limited approach boundary?

• A. NFPA 70
• B. NFPA 13
• C. NFPA 72
• D. NFPA 99

Answer: (D)

The idea being tested is where safety boundaries are set around energized electrical parts to protect workers. The limited approach boundary is defined in NFPA 70E, the standard for electrical safety in the workplace. This boundary marks the distance from exposed energized conductors or equipment within which a shock hazard exists that requires specific precautions. Within this zone, workers must be qualified and equipped with appropriate PPE, and certain procedures must be followed to safely perform tasks. NFPA 70E also covers related concepts like restricted and prohibited boundaries and the arc flash boundary, all of which together guide how close a person may approach energized parts and what protective measures are needed. The other standards listed address different areas—NFPA 70 is about electrical installations, NFPA 13 about sprinkler systems, NFPA 72 about fire alarm signaling, and NFPA 99 about health care facility equipment and life safety—and do not define these electrical safety boundaries.