NESC Arc Flash Tables vs ArcPro Calcs
NESC Arc Flash Tables vs ArcPro Calcs
(OP)
There was a thread on this several months ago, but it's locked, so I'll start a new one.
I'm trying to compare my results using ArcPro against the values in the NESC arc-flash table 410-2 at 69 kV. My results seem to be much less than the basis used for the NESC Table.
I thought I was using the arc gap and working distance as defined in the table footnotes, but something is obviously different. Most likely candidate seems to be the working distance. I used the 39" minimum approach distance from Table 441-1 minus twice the assumed arc gap and got about 31".
Has anyone been able to match the NESC table results using ArcPro?
I'm trying to compare my results using ArcPro against the values in the NESC arc-flash table 410-2 at 69 kV. My results seem to be much less than the basis used for the NESC Table.
I thought I was using the arc gap and working distance as defined in the table footnotes, but something is obviously different. Most likely candidate seems to be the working distance. I used the 39" minimum approach distance from Table 441-1 minus twice the assumed arc gap and got about 31".
Has anyone been able to match the NESC table results using ArcPro?






RE: NESC Arc Flash Tables vs ArcPro Calcs
I know this is probably not necessary, but have you used the multipliers in ArcPro for single phase, three phase, etc? (It's been a while since I've used ArcPro, forgive me)
Also, although NESC says they were calculated using "commercially available software" is there a possibility they used the free Duke Energy calculator?
RE: NESC Arc Flash Tables vs ArcPro Calcs
For the higher voltages, my results are consistently lower, although not by a consistent amount. If the footnotes in the tables are correct, there are some discontinuities in the assumptions made for arc gap. But I suspect the main discrepancy is what was used for the distance to arc and what was used as the Minimum Approach Distance.
I have not tried applying the factors for single-phase arc in box or three phase, but I don't see why they would start applying those at higher voltages when they apparently didn't apply them at 1-46 kV. But I'll take a look.
I traded e-mails with another engineer who is having similar issues. He has sent a request to NESC committee member who was said to be the expert on the tables, but has received no response.
RE: NESC Arc Flash Tables vs ArcPro Calcs
The 07 code changed it to "...a commercially available software program."