A King wrote:

Annex D of the NFPA-70E has formulas for calculating the arc flash boundary. However, I don't think that's the answer you're looking for... and I'm not sure I completely understand your question.

It sounded like to me that he was asking if you know the incident energy, how close can you get to the arc flash and be protected at PPE rated at

**HRC 2**.

i.e. what is the (working) distance from a known incident energy to the point where the incident energy is reduced to 8 cal/cm^2, as opposed to being reduced to 1.2 cal/cm^2 which is why i suggested solving the equasion for working distance.

I actually made up a spreadsheet in excel where i could get the incident energy at 6", 12", 18", 24", 36" . . . so I could say that the incident energy may be 51.56 cal/cm^2 at 18" but at 24" it is 32.16 cal/cm^2, and at 36" it is 16.53 cal/cm^2, and so forth.

[

**modified HRC to 2 to agree with 8 cal/cm^2**]