Blog » Montage of Manhole Explosions from Gas build up. Excellent study from EPRI.
Here is what methane buildup in manholes can do. Arc flash is about the same but more power from a burn perspective on those in the hole from arc plasma in some cases.
Click here to see the video. It is one of my YouTube Favorites.
Hugh Hoagland is the foremost tester of clothing and PPE exposed to electrical arcs and is an arc flash expert. Read more about Hugh.