Shock Approach Boundaries, Qualified Persons, and Energized Work (NFPA 70E)

Besides the arc-flash boundary (heat), NFPA 70E defines shock boundaries (contact risk) and strict rules about who may approach energized parts and when energized work is allowed.

1. The two shock approach boundaries

• Limited Approach Boundary — the approach limit for unqualified persons. They may not cross it unless a qualified person continuously escorts them and advises them of the hazards.
• Restricted Approach Boundary — closer in; only a qualified person with proper PPE and a plan may cross it. Unqualified persons may NEVER cross the restricted approach boundary.

(These are about shock/contact risk — separate from the arc-flash boundary, which is about incident-energy/heat.)

2. Qualified vs. unqualified

A qualified person has the training and knowledge of the equipment's construction and operation and the hazards involved, and can avoid unexpected contact with energized parts. An unqualified person lacks that training.