arc flash labels

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Hello folks. My company has recently undergone an arc flah assement complete with labels and all. I am to explain what these arc flash labels mean to all maintenance personnel and other affected employees and I am confused as to why I have more than one shock approach boundary. EX;Limited approach;42 inches, Restricted approach;No contact, Prohibited approach;No contact. I would assume I only need to know the limited approach. Thank you ahead of time
 

wbdvt

Senior Member
Location
Rutland, VT, USA
Occupation
Electrical Engineer, PE
Is this a new study? NFPA 70E-2015 has dropped the Prohibited Approach Boundary. That is no longer applicable.

The definitions are found in NFPA 70E:

Limited Approach: approach limit at a distance from an exposed energized electrical conductor or part within which a shock hazard exists.

Restricted Approach: approach limit at a distance from an exposed energized electrical conductor or part within which there is an increased likelihood of electricl shock due to electrical arc over.

These are brief descriptions. Refer to NFPA 70E Annex C for a more detailed explanation of Limits of Approach.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Have someone look at the contract from the company that did the assessment, typically one of their representatives should give a training session with all explanations as part of the contract.

Roger
 

jdsmith

Senior Member
Location
Ohio
In brief:

As wbdvt indicated NFPA 70E-2015 dropped the Prohibited Approach Boundary completely.

If working inside the restricted approach boundary the qualified worker needs insulated tools and voltage rated gloves.

Unqualified workers should not be inside of the limited approach boundary.

NFPA 70E provides much more complete explanations, there are some nuances I'm leaving out here for brevity.


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