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Which "interactions" do you feel create a possible arc flash hazard?
Racking in/out a circuit breaker - doors closed
Inserting a MCC bucket
Operating a motor starter (doors closed, normal operation)
Operating a switchgear circuit breaker (on / off)
Operating any circuit breaker/fused switch 800 amps and above
Operating any circuit breaker/fused switch between 100 and 800 amps
Operating any circuit breaker/fused switch 100 amps and less
We have other interactions too? - your comments welcome.
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 Post subject: Interaction with Equipment
PostPosted: Sun Dec 05, 2010 2:27 pm 
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Joined: Mon Sep 17, 2007 5:00 pm
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Location: Scottsdale, Arizona
The 2009 Edition of NFPA 70E definition of Arc Flash Hazard added FPN No. 1 that states an arc flash hazard may exist when:

[INDENT]“equipment in a guarded or enclosed condition, provided a person is interacting with equipment in such a manner that could cause an electric arc as possibly creating an arc flash hazard.” [/INDENT]
Many suggest this was not well defined. Which of the following do you consider a possible “interaction” which could create an arc flash hazard and require PPE (480V and below)?

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PostPosted: Mon Dec 13, 2010 12:23 pm 

Joined: Sun Dec 12, 2010 5:00 pm
Posts: 27
Location: Idaho
Electrical Lead

As most of you now know, the wording in the new NFPA 70E confuses most. What are we going to do with all the employees in the workplace that throw these disconnects for LOTO on a daily basis which is by definition inside the arc flash boundary. This creates problems in all industry, not just the electrical. Is this really the intent of the NFPA for everyone to have on their PPE or just the electrician working on "Exposed Live Parts"?


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PostPosted: Mon Dec 13, 2010 2:24 pm 
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Joined: Mon Jan 18, 2010 11:35 am
Posts: 551
Location: Wisconsin
gastoor wrote:
Is this really the intent of the NFPA for everyone to have on their PPE or just the electrician working on "Exposed Live Parts"?


The intent is that all employees, not just electricians, wear the appropriate PPE.

The gray area question is which interactions are "in such a manner that could cause an electric arc as possibly creating an arc flash hazard.”


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PostPosted: Tue Dec 14, 2010 11:11 am 

Joined: Sun Dec 12, 2010 5:00 pm
Posts: 27
Location: Idaho
I don't dispute that a local disconnect may create an arc at some point but if LOTO is properly done, there is no load on the disconnect because either control power or power to the starter has been removed before lockout. Because my label has an arc flash boundary printed on it, then PPE applies except for the rest of the FPN, it says that "under normal operation conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard" and the word "normal" should include operating the handle. I know this part of the requirement has already been disputed, but is there anymore discussion for it. How is everyone in industry reading this? Does anyone have statistics or such for anyone other than electricians getting burned or killed by arc flash when just throwing the handle on the disconnect? :confused:


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PostPosted: Sat Dec 18, 2010 5:03 pm 

Joined: Mon Dec 06, 2010 11:33 am
Posts: 4
Location: LUBBOCK TX
One is too many

Yes I know Personally of a recent event which burned a man's arm from operating a closed disconnect.
Fine Print Notes are non-mandatory and are for informational purposes only.
Souns like you want to use a FPN as a basis to violate the requirement for appropriate PPE. Read NFPA70E 120.2(A), and 130.1(A). I interpret the FPN No. 3: of Article 130.1 to be providing information relevant to reducing potential arc hazard by incorporating proven methods into the design of an electrical system. Also, read 130.2. with all this considered, is the justification for not requiring the appropriate PPE, that an arcing event Probably wont't happen. Anytime you tell yourself, "it'll be okay this time", think about how your family is going to react when they see you in the burn unit, if your wrong. God forbid the worst case.


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PostPosted: Wed Dec 29, 2010 8:53 pm 
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Joined: Thu Oct 18, 2007 7:10 pm
Posts: 263
Location: NW USA
In the poll above I selected every category, because I understand there are those who write codes that have little concept about how work gets accomplished, that feel it is neccessary to always have all protections in place. I have debated ad-nauseum about the need to suit up to operate switchgear that is in good condition, within it's ratings and buttoned up, and realize that some of the code writers, perhaps financed by those who manufacture arc resistant switchgear; will always and forever declare that unless rated arc resistant, all switchgear must be operated whilst wearing rated ppe.

That does contradict the principle supporting the prescriptive tables in NFPA 70E that assign a lower risk category for less intrusive work. And that also disagrees with our State's Labor and industry expert who stated that he considers what work is likely to disturb the field around an exposed conductor; but now common sense is entering the thought process.


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PostPosted: Fri Dec 31, 2010 10:43 am 

Joined: Sun Dec 12, 2010 5:00 pm
Posts: 27
Location: Idaho
Electrical Lead

I believe I have been misinterpreted. What our plant is trying to find out is that do all 400 employees that come to work wear Category 0 clothing. As of present, long sleeve non-melting clothing when perhaps maybe once or twice a week, they have to lock out a machine. Our electricians wear FR clothing on a daily basis because they open up the doors and test equipment daily. We have all our equipment labeled and it states that a person cannot be within the Arc Flash Boundary which on most of our local disconnects is less that 12". Therefore before attaching their locks, they have to have the appropriate PPE. I am not using fpn to get away with not putting on PPE, I just do not see the hazard when doors are closed and equipment is maintained properly-every person walks by a piece of electrical equipment everyday, so should they be suited up when they do?? :rolleyes:


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PostPosted: Wed Jan 12, 2011 4:40 am 

Joined: Fri Jul 10, 2009 10:14 am
Posts: 32
Location: West Central, OH
Our position

Later this year, we are updating the PPE requirement for non electrical workers who operate disconnect switch's (mainly MCC handles). The good part is that they are wearing ATPV rated clothes to start with so will be adding a face shield, hearing protection, gloves and training to understand the change. The training will include a "show me you know what to do" after the computer training is completed. We have not have an incident but feel this is the "safe" way to move forward. I can share other stories about what we have done in the past year for "safety" that make my head spin (must wear cut resistant gloves before using a "safety" box cutter to open a box in the office).


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PostPosted: Thu Jan 13, 2011 9:40 am 
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Joined: Thu Jan 10, 2008 8:49 pm
Posts: 510
Location: New England
The present revision of Art 130 deals with 'work on energized parts' or in areas with dead fronts where operation of switching could present a hazard because of the significant energy being switched (ie, the blast could blow the doors off). The latter is generally considered to include switchgear, but not necessarily MCC buckets and molded case breakers (althought others will argue that it does).

What I suggest is that you establish a threshold. It could be exclusive to switchgear, or any circuit over 800amps, or over 400 amps, or over 100amps.
Or you could go by an incident energy level. Nema 1 enclosures are built to different structual standards, and are not really rated for a blast pressure (unless specificially so designed) but I would be comfortable to opinion that an 8 cal/cm2 incident energy arc would not blow open the average MCC bucket door.

I am more apt to set thresholds based upon incident energy levels rather than amperage, as IE is a direct measurement, and amps is a correlated measurement with clearing time being a variable.

I would not , dress out the 400 employees who have to do LOTO, but I would provide documentation of its review and the decisions made and why.

Yes, I understand that this will not eliminate every incident, but this is a balance between maintaining a operable business and running a good safety program.


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PostPosted: Tue Feb 15, 2011 2:33 pm 

Joined: Wed Nov 21, 2007 8:23 am
Posts: 4
Location: Cleveland, OH
After reviewing table 130.7(C)(9), I took a step back. If a person has no interaction with equipment and is performing thermography or a basic visual inspection outside of the restricted approach boundary on 4160V gear, a level 3 HRC is prescribed, but according to the definition of an arc flash hazard... "provided a person is interacting with the equipment in such a manner that could cause an electric arc." WHAT? Assuming no mechanical moving parts or fuses that could be an ignition source, why would there be an HRC or even an incident energy associated with this. I understand opening doors and removing panels to do the inspection, PPE should be worn, but staying outside of the restricted approach boundary with no contact performing a visual inspection?... I'm done trying to figure this out! Can someone point me in the right direction in solve my issue? In addition, if an analysis is performed (trumping the 130.7(C)(9) table), and an incident energy and associated PPE is required, would this still require the same level of PPE for visual inspections?
:confused:


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