
Good god thats nuts... http://www.youtube.com/watch?v=NQQMK1Rvq0A&feature=related
that's awesome ! What on earth caused it ?
Its an air switch...
The contacts were closed.....But to turn off the switch the contacts are pulled appart....thus creating that arc...The air can conduct that sort of
current for a second or two before the path becomes too great and the flow stops....
excellent love that

Wow 
you think that is nuts have a look at this
I think I can out trump that with this....
Famous video..
http://www.youtube.com/watch?v=Z3q9WdjD5wc
They should definately use a relay!