Which boundary is defined as the limit within which a shock hazard exists due to proximity to an energized part?

• A. Limited Approach boundary
• B. Restricted Approach boundary
• C. Prohibited boundary
• D. Arc flash boundary

Answer: (A)

The main idea is understanding how NFPA 70E defines zones around energized parts to manage shock risk. The distance described as the limit within which a shock hazard exists due to proximity to an energized part is the Limited Approach Boundary. This boundary marks the point where proximity to an energized component creates a potential shock hazard, and work within this zone requires appropriate procedures and PPE and must be performed by or under the supervision of a qualified person. The Prohibited Boundary is the closest zone, where entering or touching energized parts is not allowed. The Restricted Boundary is closer still and requires additional controls and PPE for entry. Arc flash boundary, by contrast, relates to thermal energy from arcing faults, not shock risk from proximity. So the limit defined by proximity to an energized part is the Limited Approach Boundary.