I agree as well it would PROBABLY trip the breaker as well, but like what was mentioned above, if its local it may not.. Here is a senario.. its a rural area, rural building, where the high voltage is brought to a transformer on the customer's property, so the trans serves no other load but the one building... now say for example its not the secondary service drop thats down but the PRIMARY... That generator could energize the transformer backwards, and liven up the now downed primary line... If a lineman were to come into contact he would "get it" and get it good!... Remember it does not take much current to throw the heart into ventricular defribrilation( think its spelled correct!) should the current take that path And with something at minimum of 2.4kV present,there is going to be a fair current being pushed through whoever is now completing the circuit, not to mention the severe burns that would happen...

Scary isn't it?

A.D