I just received notice that the first draft report of what will ultimately be the 2017 Edition of the National Electrical Code was just issued today, June 22, 2015. One item of interest regarding arc flash is the addition of an instantaneous trip function to Article 240.87 as being a means of arc energy reduction. You will need to set up a login if you do not have one.
First Draft Report 2017 Edition of NFPA70E