# Ground Resistivity and Arc-Flash



## hebertjl5 (Aug 30, 2016)

Hi all!

Been cranking through problems and everything else (everything else being the mountain of stuff and things on my home office desk) for the past couple months.

I'm looking for some straight forward literature in the areas of ground resistivity and arc-flash. Equations to follow the different examples. I'm trying to game out all scenarios so that I can't be taken by surprise in October...

Does anyone have any recommendations? Thank you in advance!


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## allgood (Aug 31, 2016)

I found some formulas for ARC flash calcs in Annex D of NFPA 70. I haven't found any sample problems to test them out though


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## allgood (Aug 31, 2016)

NFPA 70E I mean.


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## hebertjl5 (Sep 7, 2016)

Thank you! I'll give it a peek.


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## saltedbutter101 (Oct 9, 2016)

I would recommend knowing how to calculate the arc flash incident energy using NFPA 70E as stated above.


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## cupojoe PE PMP (Oct 10, 2016)

Probably better to understand the rules/needs related to arc flash spelled out NFPA 70E rather than actual equations. Arc flash studies have so many variables that I couldn't imagine trying to do any useful calculations on anything but the absolute simplest scenarios. I can't imagine what type of question you would get that you could solve in 6 minutes.


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## ukiecan (Nov 3, 2016)

check http://arcadvisor.com/calculation-examples for three-phase, single-phase and dc arc flash calculation examples


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