NFPA 70E Arc Flash Boundries
- Thread starter mjc1060
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mayanees
Senior Member
- Location
- Westminster, MD
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- Electrical Engineer and Master Electrician
No...
No...
The arc flash boundary alerting requirement is met by it being displayed on the AF label.
It's a good idea, IMO, to use additional techniques to identify the boundary, but along with that then there would need to be sitewide training so everyone could know what's being done (i.e. red/yellow/orange paint for AFB)
John M
No...
The arc flash boundary alerting requirement is met by it being displayed on the AF label.
It's a good idea, IMO, to use additional techniques to identify the boundary, but along with that then there would need to be sitewide training so everyone could know what's being done (i.e. red/yellow/orange paint for AFB)
John M
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
There is no need to mark the floor, just as there is no need to permanently mark working clearances. The AF boundary only exists when someone is "interacting in a manner that would cause an arc" not just simple interaction.
Many Electrical Safe Work Practices programs require the use of 'caution tape' or other portable/temporary barricades.
the blur
Senior Member
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- cyberspace
what if electrical panels are in an employee break room. how much room has to be between the panels and a lunch table ?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
None, other than the NEC standard clear space.
The arc flash boundary only applies when there is 'interaction that can cause an arc'.
Interaction
Interaction
How would you define a simple interaction verses an interaction that would cause an arc?
Interaction
How would you define a simple interaction verses an interaction that would cause an arc?
zog
Senior Member
- Location
- Charlotte, NC
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
NFPA70E is fraught with what needs to be done but, purposely, there is not much detail on how to accomplish it.
See the NFPA70E definition of Arc Flash Hazard.
Informational Note #1 says normal operation is normally not an issue, Note #2 is the reference for Zog's posting directing you to the task tables.
But then to make things clearer (?), the committee added Note #2 to 130.7(A), which effectively says; in the experience of the [NFPA70E] committee members normal operation of properly maintained enclosed equipment <600V is not likely a hazard.
So there is no single correct answer, but, statistically it is worse to be operating equipment, than it is walking past or simply sitting in the same room with it.
See the NFPA70E definition of Arc Flash Hazard.
Informational Note #1 says normal operation is normally not an issue, Note #2 is the reference for Zog's posting directing you to the task tables.
But then to make things clearer (?), the committee added Note #2 to 130.7(A), which effectively says; in the experience of the [NFPA70E] committee members normal operation of properly maintained enclosed equipment <600V is not likely a hazard.
So there is no single correct answer, but, statistically it is worse to be operating equipment, than it is walking past or simply sitting in the same room with it.
kenaslan
Senior Member
- Location
- Billings MT
No. Only the equipment itself must be labeled, and only for when the incindent energy is larger than 1.2 cal/cm sq. (see attached NFPA 130.5(C)
View attachment 7051
View attachment 7051
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
130.5(C) makes absolutely no mention of an incident energy level cut off /exclusion. If you are going to examine, service, adjust, or maintain it, while energized, it needs to be labeled.
kenaslan
Senior Member
- Location
- Billings MT
See 3rd line down in blue, The above was taken from the NFPA 70E Handbook.
"Only the equipment where the incident energy level is greater than 1.2 cal/cm2 needs to be marked, but that decision depends on a facility?s safety program."
"Only the equipment where the incident energy level is greater than 1.2 cal/cm2 needs to be marked, but that decision depends on a facility?s safety program."
kenaslan
Senior Member
- Location
- Billings MT
It is the third line down in the blue section.
130(A) Arc Flash Boundary. The arc flash boundary for systems 50 volts and greater shall be
the distance at which the incident energy equals 5 J/cm2 (1.2 cal/cm2).
"The arc flash boundary is the boundary determined either through calculation or through the
use of Table 130.7(C)(15); it separates an area in which a person is potentially exposed to a
second-degree burn injury from an area in which the potential for injury does not include a
second-degree burn. All body parts closer to an arc flash hazard than the arc flash boundary
must be protected from the potential thermal effects of the hazard. The arc flash boundary is
established at the point where the amount of incident energy that an employee could be exposed
to is 1.2 cal/cm2 or greater. If the incident energy is less than 1.2 cal/cm2, burns could
occur, but they will not be second-degree or worse."
energy less than 1.2 cal/cm2 need not be addressed
130(A) Arc Flash Boundary. The arc flash boundary for systems 50 volts and greater shall be
the distance at which the incident energy equals 5 J/cm2 (1.2 cal/cm2).
"The arc flash boundary is the boundary determined either through calculation or through the
use of Table 130.7(C)(15); it separates an area in which a person is potentially exposed to a
second-degree burn injury from an area in which the potential for injury does not include a
second-degree burn. All body parts closer to an arc flash hazard than the arc flash boundary
must be protected from the potential thermal effects of the hazard. The arc flash boundary is
established at the point where the amount of incident energy that an employee could be exposed
to is 1.2 cal/cm2 or greater. If the incident energy is less than 1.2 cal/cm2, burns could
occur, but they will not be second-degree or worse."
energy less than 1.2 cal/cm2 need not be addressed
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
The blue text in the handbook is not part of the standard. This text is someone's personal opinion.
kenaslan
Senior Member
- Location
- Billings MT
I would respectfully disagree. True it is not part of the original text, it is an explanation endorsed by the NFPA, written by the NFPA. Also 130(A) states ?Arc Flash Boundary. The arc flash boundary for systems 50 volts and greater shall be
the distance at which the incident energy equals 5 J/cm2 (1.2 cal/cm2).?, hence no labeling requirement exist for under 1.2 cal/cm2 as the boundary itself is 1.2 cal/cm2.
On a side note, I print arc flash labels daily for many engineering firms and have yet to print any with a level of under 1.2
Time for the weekend my Harley is calling out my name.
the distance at which the incident energy equals 5 J/cm2 (1.2 cal/cm2).?, hence no labeling requirement exist for under 1.2 cal/cm2 as the boundary itself is 1.2 cal/cm2.
On a side note, I print arc flash labels daily for many engineering firms and have yet to print any with a level of under 1.2
Time for the weekend my Harley is calling out my name.
the blur
Senior Member
- Location
- cyberspace
I'm in my kids elementry school, and the panel(s) are in the hallway. it's locked, but they obviously work on it at times. how do they draw the boundry ? close the hallway ?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Yes you may disagree.
The blue text is not'endorsed nor witten by the NFPA, it is simply someones opninon that the NFPA publishes.
I have printed and installed thousands of labels on equipment where the incident energy is less than 1.2 cal/cm?.
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