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Arc Flash PPE 31 cal/cm^2

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tem1234

Electrical
Jun 13, 2007
192
Hi,

I have a question regarding AFH. Here's a hypothecal case. If you have a system rated 28 cal/cm^2, you should have a cat4 PPE so with a minimum arc rating of 40 cal/cm^2

But...if you have a PPE rated at 31 cal/cm^2 (there's some equipment rated at this level), can you work at this place?

I would say yes, since the incident energy is less than the arc rating of the PPE (and it's not too close), but in NFPA 70E, it is written that for a cat4 you should have 40 cal/cm^2 minimum. Maybe NFA are referring on the simplified table method instead of the calculated one. I would like to know your opinion about this.

Thanks
 
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40 cal/cm2 is the MAXIMUM for PPE #4. If the worker is wearing PPE suitable for the maximum arc energy at the specified working distance, then it's OK.

So in general, 28 cal/cm2 requires Hazard/Risk Category #4 PPE per NFPA 70E. Category #4 PPE is good up to a maximum of 40 cal/cm2. So with Category #4 PPE on, the worker is protected up to 40 cal/cm2. In theory.



 
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