Approach Boundaries
The risk from exposed live parts depends on your distance from the parts.
Three "boundaries" are key to protecting yourself from electric shock, and one is key to protecting you from arc flashes or blasts. These boundaries are set by the National Fire Protection Association (NFPA 70E) and the Canadian Standards Association (CSA Z462).
- The Restricted Approach Boundary: Only a qualified person may cross this shock-protection boundary. The qualified person must use appropriate safe work practices and PPE identified by the shock risk assessment. A qualified person has demonstrated the skills and knowledge needed to identify electrical hazards and perform the assigned work safely.
- An Energized Electrical Work Permit (EEWP) is required when applicable; NFPA 70E identifies limited exceptions for specified tasks.
- The use of shock protection techniques and equipment is required.
- The qualified person must wear appropriate shock-protection PPE.
- The qualified person must follow an approved work plan and minimize the time that any body part is within the restricted space.
- The Limited Approach Boundary: NFPA 70E defines the limited approach boundary as a shock protection boundary to be crossed by only qualified persons (at a distance from a live part), which is not to be crossed by unqualified persons unless escorted by a qualified person.
- This boundary is the minimum distance from the energized item at which unqualified personnel may safely stand.
- No untrained personnel may approach any closer to the energized item than this boundary.
- A qualified person must use appropriate PPE and be trained to perform the required work to cross the limited approach boundary and enter the limited space.
- Flash Protection Boundary (FPB): The FPB is the farthest established boundary from the energy source and is considered a safe approach distance from energized equipment or parts.
- Only persons wearing appropriate personal protective clothing and equipment for the Arc Flash Boundary, as determined by an Arc Flash Risk Assessment, may approach closer than the FPB.
Knowledge Check Choose the best answer for the question.
5-5. When working around high voltage components, no untrained personnel may approach any closer to the energized item than the _____.
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