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#174309 - 02/01/08 02:20 PM NFPA 70E Question
MikeF Offline
New Member
Registered: 02/01/08
Posts: 3
Loc: Ca.
Is flash PPE required inside the limited/restricted approach boundaries or not until the prohibited approach boundary is crossed? Can a visual inspection be done from the restricted zone without flash PPE?
Thanks, Mike
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#174313 - 02/01/08 03:13 PM Re: NFPA 70E Question [Re: MikeF]
Gregtaylor Offline
Member
Registered: 03/02/05
Posts: 212
Loc: Boise, Idaho, USA
This is one of the places where the NFPA 70E rules become very confusing. The boundaries you refer to are for SHOCK hazard, not flash hazard. Flash hazard and boundaries are calculated individually for the circumstance. The way it usually works out is that flash hazard PPE would be required within the shock hazard restricted/prohibited zones but not the limited zone. This is not always true however. Very high energy circumstances could extend the flash hazard areas well outside the shock hazard limited zone.
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#174314 - 02/01/08 03:15 PM Re: NFPA 70E Question [Re: MikeF]
ghost307 Offline
Member
Registered: 05/09/05
Posts: 899
Loc: Chicago Illinois USA
PPE is needed in order to enter the limited/restricted zone.
Nothing will allow you to enter the prohibited zone and survive if there is an event.

You would need to de-energize the equipment (and make the prohibited zone go to zero) if you want to get that close to the equipment.
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Ghost307
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#174318 - 02/01/08 04:20 PM Re: NFPA 70E Question [Re: ghost307]
MikeF Offline
New Member
Registered: 02/01/08
Posts: 3
Loc: Ca.
Definitely confusing....so SHOCK protection really amounts to rubber gloves, correct? FLASH protection is everything else? And if a flash approach boundary is determined to be at 4 feet, then all the other boundaries are pretty much out the window (?). Full protection from 4 feet in, in that situation?
Thanks so much!
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#174379 - 02/03/08 08:01 AM Re: NFPA 70E Question [Re: MikeF]
Zog Offline
Member
Registered: 09/13/05
Posts: 120
Loc: Charlotte, NC
Mike your answer is corrct assuming this is 600V or less we are talking about.

Ghost you seem to have the Arc Flash and Shock boundaries confused.

Greg, well put.

LAB may only be crossed by Qualified Personel (As defined in the 70E). RAB requires shock protection, usually just means gloves but can be more. PAB should be treated as the boundary you never cross but special training and hazard analysis would allow crossing. Shock boundaries only apply if there are exposed live parts.

Neither of these have anything to do with the arc flash boundary, the shock boundaries are dependant on voltage, the flash boundary has nothing to do with voltage levels, it is based on available fault current and clearing time of the protective device. PPE for flash protection must be worn any time you cross the Arc Flash boundary and "interact" with the equipment, weather the live parts are exposed or covered.
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MV/HV Testing Specialist, "BKRMAN"
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