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 Post subject: Where else is Arc Flash present?
PostPosted: Fri Aug 17, 2012 7:33 am 
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Just trying to educate myself on where Arc Flash studies/Arc Flash scenarios may occur. I know obvious ones are large /small industrial facitlies. However, I've heard places like airports? ships? need them as well? How common is that? Again, trying to add on to my prior thread to find where this industry is heading


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PostPosted: Mon Aug 20, 2012 7:24 am 
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The reality is arc flash can occur anywhere there is electricity. Everytime I plug in my George Forman (no on-off switch) I see an arc flash - as small as it is. As far as looking at this a career choice - there is plenty of work but plenty of people doing it. If you have clients you are working with you can offer it as a service in addition to what you already do for them.

As for airports, malls, and the like the NEC only requires a simple sticker and OSHA/MSHA have not fully adopted it so it has not become an offical requirment excpt under the general duty clause. It is my experience that only when someone pushes for the study or an insurance company requires it is the only time it is done.

I have a client that decided it was required for safety and I told them it will change the way they do business and they fully accepted the additional cost - including over one million dollars for the study. That did not include any changes required to mitigate any issues or future work practice changes.

I do caution engineers before getting into the field to be sure to get all the knowledge they can before heading off into the wild arc flash west. Many engineers simply jsut push the button without really knowing what is means or how to mitigate the issues. I have a lot projects going and cleaning up someone just pushing the button for my clients.


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PostPosted: Mon Aug 20, 2012 8:02 am 
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engrick wrote:
The reality is arc flash can occur anywhere there is electricity. Everytime I plug in my George Forman (no on-off switch) I see an arc flash - as small as it is.

That's only an electrical arc when you open/close a circuit under load. That's not an arc flash. It cannot develop into an arc flash (not because it's 120 VAC, but because you have the load in series with the arc).


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PostPosted: Mon Aug 20, 2012 4:42 pm 
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Vincent B. wrote:
That's only an electrical arc when you open/close a circuit under load. That's not an arc flash. It cannot develop into an arc flash (not because it's 120 VAC, but because you have the load in series with the arc).


Then how come I can strike an arc with a welder at far less voltage than that, and if I do any significant amount of arc welding without eye or skin protection, I get a very nasty "sun burn", itching/stinging eyes, and potentially even corneal damage? To say nothing of the burns I can get from the pure radiative heat from the arc welding process?

"Arc flash" is a combination of physical phenomena of the effect of the light and radiation released from an electric arc. Arc blast is generally considered the concussive force, shrapnel, and hot vapors/plasma that is released though obviously this is not a hard and fast rule.

You can get an arc in a hard vacuum, too. Don't even need air to be present. This is the limiting factor on the reason why you don't find vacuum interrupters much above 600 A continuous duty.


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PostPosted: Tue Aug 21, 2012 5:26 am 
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PaulEngr wrote:
"Arc flash" is a combination of physical phenomena of the effect of the light and radiation released from an electric arc. Arc blast is generally considered the concussive force, shrapnel, and hot vapors/plasma that is released though obviously this is not a hard and fast rule.

Point taken about definitions, but I still don't think the arc created when unplugging a George Foreman (or a running fridge) is an arc flash.


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PostPosted: Mon Aug 27, 2012 3:18 pm 
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I did not intend on stating that my george Forman is a category 1-D arc flash - the point is arc flash can occur anywhere. That is why residential wiring requires AFCI. The point of the question appeared to be arcnewb looking to get into the field and wondering where AF exists. AF has become more than some high-level software and IEEE standard.


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