I have studied extensive data on electrical incidents (some dating back to the early 70s). e-Hazard has investigated over 150 electrical arc flash accidents and some near hits / near hits. Almost all instances had some form of a work permit system which had some inherent deficiency that allowed the incident to happen. Interestingly enough, using modern day OSHA (energy control requirements) and NFPA 70E - 2015 requirements, most of the situations did not warrant the issuing of a permit. The deficiencies in the permit resided (mainly) from the multiple hazard scenario or not addressing subsidiary risks.
To summarize: these incidents occurred with a isolation (LO/TO) type permit, an Energized electrical work permit, and instances where a permit was not required.
With the uptick in renewable energies such as photovoltaic (PV) farms, wind generation, and concentrating solar, live work is unavoidable. The other areas like municipal / wastewater treatment facilities also pose the same challenge. We favor a periodic site audit as required by OSHA and the NFPA70E - 2015, followed by the review of the electrical safety program. It is in these areas that the most gaps / deficiencies are found!