Arc Flash - Where do you stop?
Arc Flash - Where do you stop?
(OP)
How far down in the electrical system do you carry arc flash analysis? It seems one has to go to every load hanging off of a panel that an electrician might work on live. Carried to an extreme, that means that every 277V light fixture and every load downstream of a 480V distribution panel needs an arc flash analysis.






RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
If you do not do an analysis below this point you would need to default to the 70E tables. For panelboards 240 and below some tasks are HRC 1.
There was a proposal for the 2009 70E that was accepted that will no longer allow generic labels, the new labeling requirement will require either the Ei or HRC.
RE: Arc Flash - Where do you stop?
DO you have a link to the proposed 2009 70E standards. I also agree with you that there is a difference on the requirements of 70E and IEEE1584. Thanks.
RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
Starting next week all of my courses will include notes for each part of 70E that will be affected by these changes.
RE: Arc Flash - Where do you stop?
http://w
Also you can call the NFPA and ask for a hard copy...they are free. Comments on the proposed changes will be accepted until 8/31/07. The final document will be voted on at the June 2008 meeting.
Don
RE: Arc Flash - Where do you stop?
To do this right, it seems you need to do arc flash analysis at every one of these elements. I do not see too much discussion of the magnitude of the data research and data entry involved. Or maybe I am missing a general concept that a rule is developed for the facility, "For this list of equipment, where you might have considered working on it live in the past, that is not allowed any longer."
RE: Arc Flash - Where do you stop?
My messy problem is that a guy pays me to provide him with arc flash analysis to meet code requirements, and without clear guidance on where to stop, there is an order of magnitude difference on what this means. The scope needs to be in the contract up front I guess, but it would be nice if there was guidance beyond, "Well, no one seems interested in that normally, but I have no technical reason why it should not be included, so I guess I could include it in the calc if you want me too." Sounds pretty unprofessional an answer.
RE: Arc Flash - Where do you stop?
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RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
70E does not address flash hazard labeling requirements. NFPA 70 (NEC) requires labeling indicating presence of arc flash hazard (but not specific energy levels) for switchboards, panelboards, industrial control panels, meter sockets and motor control centers in other than residential occupancies that are likely to require maintenance while energized.
RE: Arc Flash - Where do you stop?
This one may be more relavent: thread238-171682: New to Short Circuit / Arc Flash Study
NFPA 70E is based on IEEE 1584 and recognizes its use.
RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
Now add arc flash, I need to find the data on every breaker in the panel, every feed off of it, and then find the fault current at the end load and how long it will take to clear that fault.
I have a 10 fold increase in the work level to analyze the panel. WOW. Billable hours rock.
RE: Arc Flash - Where do you stop?
RE: Arc Flash - Where do you stop?
I recently visited a local automotive plant, they have identified 5420 panels that need Arc Flash evals. Lots of billable hours for lots of people.... but expect your next pickup truck to cost just a little more.