explosive situation?

Precisely.

The flashpoint for a liquid is approximately the temperature a which the partial pressure of the vapor over the liquid reaches the LEL.

In theory, I suppose they are exactly the same but in practice flashpoint is determined in a laboratory and there are at least two methods used that can give slightly different results--open cup and closed cup.

That jibes w/ my recollections -- vague memories say they were playing with circa 250KV.

Shall I mention the time I saw somebody swing a crane boom in to the _feeder_ lines to an operating sub-station, and only about 500 ft away from the sub-station. The _flame_ front was merely a couple of =hundred= feet *wide*. It went away fairly quickly -- like a second or so -- but there were also several 'booms' and small clouds of smoke from the station itself -- apparently 'protective' disconnects when the three-phase feed went *that* unbalanced.

I've heard _one_ louder noise than that -- a lightning strike on a telephone pole about 50' outside our back door. I *saw* the glass patio-doors I was sitting not 10' away from bulge (about 3 inches!!) from the pressure wave.

Fun. When I was a kid I was tossing a javelin (dead and desiccated hemlock plant with the root still on the tip) over the powerlines.

Was. On the last vault over, the back struck the near-side powerline on the top, and the front settled down on the far side. Smoke, and when it started flaming I turned to run inside and plead my case, when I saw the front side of the house light up in a bright blue light. I ducked and turned to see remnants of my javelin spiraling down in flame.

Couple minutes later and a PG&E truck came tooling by...

er