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 Post subject: Marking Limits of Approach
PostPosted: Wed Sep 03, 2008 12:25 pm 

Joined: Wed Aug 20, 2008 6:33 am
Posts: 5
I do not see any mention of marking limits of approach in NFPA 70E. To me it would only make sense to mark the flash protection boundery on the floor. In order to read the label one would have to cross the flash protection boundery. Am I missing something here?


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PostPosted: Wed Sep 03, 2008 1:02 pm 
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Location: Charlotte, NC
cateng wrote:
I do not see any mention of marking limits of approach in NFPA 70E. To me it would only make sense to mark the flash protection boundery on the floor. In order to read the label one would have to cross the flash protection boundery. Am I missing something here?


Saw an automotive plant do that and it was a mess, way to confusing, they ending up pulling up all the markings. What if you change loads and adjust you breaker settings?

You dont need PPE to cross the FPB until you interact with the equipment.


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PostPosted: Wed Sep 03, 2008 1:24 pm 

Joined: Wed Aug 20, 2008 6:33 am
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Zog wrote:
Saw an automotive plant do that and it was a mess, way to confusing, they ending up pulling up all the markings. What if you change loads and adjust you breaker settings?

You dont need PPE to cross the FPB until you interact with the equipment.


How do you define interact?


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PostPosted: Wed Sep 03, 2008 2:56 pm 
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cateng wrote:
How do you define interact?


Do something to it, the 2009 70E will be using this term and will be in the defifitions. Switching, racking, moving wires, opening panel doors, removing covers, taking measurements, etc.....


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PostPosted: Thu Sep 04, 2008 6:06 am 

Joined: Wed Aug 20, 2008 6:33 am
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You dont need PPE to cross the FPB until you interact with the equipment.[/QUOTE]

I am sorry but I am sort of new to Arc Flash.
Where can I find this in NFPA 70E? I can not locate it.
Everything I see mandates that PPE must be worn if a person crosses the FPB, when there are exposed live parts, regardless if they are interacting with the equipment.


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PostPosted: Thu Sep 04, 2008 6:39 am 
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Joined: Mon Apr 14, 2008 7:10 am
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" No. 1: A flash hazard may exist when energized electrical conductors or
circuit parts are exposed or when they are within equipment in a guarded or
enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose a flash hazard." It is from the comments to NFPA 70E and you probably will see it in new version.


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PostPosted: Thu Sep 04, 2008 6:44 am 

Joined: Wed Aug 20, 2008 6:33 am
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Noah wrote:
" Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose a flash hazard." It is from the comments to NFPA 70E and you probably will see it in new version.


OK, but what about energized equipment that is not enclosed?


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PostPosted: Thu Sep 04, 2008 7:01 am 
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Noah wrote:
" No. 1: A flash hazard may exist when energized electrical conductors or
circuit parts are exposed or when they are within equipment in a guarded or
enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose a flash hazard." It is from the comments to NFPA 70E and you probably will see it in new version.


Read the above again in it's entirety. It says exposed provided a person is interacting with the equipment in such a manner that could cause an electric arc. I would have to assume that walking by exposed energized parts, at a reasonable distance, is not interacting with the eqpt in a way that would cause an arc. Of course if you are carrying a 10 foot aluminum ladder 3 feet away from a open 480V bus bar bus, that's another issue.

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